TWI656204B - Polishing composition, use of the same, and method for producing substrate - Google Patents

Abstract

The polishing composition contains at least one of abrasive grains and a pH adjuster selected from the group consisting of calcium carbonate, barium carbonate, manganese dioxide, zirconia, and alumina, and has a pH of 10.5 or more. Preferably, the polishing composition is used for polishing an object to be polished having a layer containing a ruthenium-containing material.

Description

Composition for polishing, method of using the same, and method for producing a substrate

The present invention relates to a polishing composition, a method of using the same, and a method of producing a substrate. The polishing composition is used, for example, for polishing an object to be polished having a layer containing a ruthenium-containing material.

In the manufacturing process of the semiconductor device, polishing may be performed in order to remove at least a part of the elemental germanium such as single crystal germanium, polycrystalline germanium (polycrystalline germanium), or amorphous germanium. Conventionally, a polishing composition disclosed in Patent Document 1 is known. The polishing composition contains colloidal cerium oxide as a main component and is adjusted to have a pH of 10 or less.

Similarly, in the manufacturing process of a semiconductor device, polishing may be performed in order to remove at least a part of the ruthenium compound such as tantalum nitride or ruthenium oxide. Conventionally, a polishing composition disclosed in Patent Document 2 is known. The polishing composition contains cerium oxide as abrasive grains and is adjusted to have a pH of 10 or less.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 7-249600

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2001-031951

Many of the conventional polishing compositions are not necessarily capable of polishing an object to be polished at a high removal speed that satisfies the requirements of the user.

An object of the present invention is to provide a polishing composition which can be suitably used, for example, for polishing an object to be polished having a layer containing a cerium-containing material.

A further object of the present invention is to provide a method of using the above polishing composition and a method of producing a substrate.

In the same aspect of the invention, there is provided a polishing composition comprising at least one of abrasive grains and a pH adjuster selected from the group consisting of calcium carbonate, barium carbonate, manganese dioxide, zirconium oxide, and aluminum oxide, and The pH is 10.5 or more. The pH of the polishing composition is preferably 12 or more. The polishing composition is preferably used for polishing an object to be polished having a layer containing a cerium-containing material. The foregoing cerium-containing material is preferably at least selected from the group consisting of elemental cerium, cerium oxide, cerium nitride, and cerium carbide. One.

In another aspect of the invention, there is provided a polishing method for polishing an object to be polished having a layer containing a ruthenium-containing material using the polishing composition.

In another aspect of the invention, there is provided a method of fabricating a substrate comprising: a polishing step of polishing a substrate having a layer comprising a germanium-containing material by the polishing method.

The polishing composition of the present invention can be suitably used for, for example, polishing an object to be polished having a layer containing a cerium-containing material.

Hereinafter, an embodiment of the polishing composition of the present invention will be described.

The polishing composition is produced by mixing the abrasive grains and water, further adding a pH adjuster, and adjusting the pH to 10.5 or more. The polishing composition is preferably used for polishing an object to be polished having a layer containing a cerium-containing material. Examples of the object to be polished having a layer containing a ruthenium-containing material include elemental oxime and ruthenium compound. Examples of the elemental lanthanide include single crystal ruthenium, polycrystalline ruthenium (polycrystalline ruthenium), and amorphous ruthenium. Examples of the ruthenium compound include ruthenium nitride, ruthenium oxide, ruthenium carbide, and the like. Grinding object, more specifically A substrate of a layer of material, or an elemental ruthenium or ruthenium compound film formed over a substrate having a layer comprising a ruthenium-containing material. A low dielectric film having a relative dielectric constant of 3 or less is contained in the ruthenium compound film.

Specific examples of the abrasive grains include calcium carbonate, barium carbonate, manganese dioxide, zirconium oxide, and aluminum oxide. These abrasive granules may be used alone or in combination of two or more.

The average particle diameter of the abrasive grains contained in the polishing composition is preferably 5 nm or more, and more preferably 10 nm or more. As the average particle size of the abrasive grains is larger, the polishing speed of the object to be polished is further increased.

The average particle diameter of the abrasive grains contained in the polishing composition is preferably 5,000 nm or less, more preferably 3,000 nm or less. As the average particle diameter of the abrasive grains is smaller, it is easier to obtain a polishing surface having a low defect and a small thickness.

The measurement of the average particle diameter of the abrasive grains can be measured by a dynamic light scattering method.

The content of the abrasive grains in the polishing composition is preferably 0.1% by mass or more, and more preferably 1% by mass or more. As the content of the abrasive grains increases, the polishing rate of the object to be polished by the polishing composition is further increased.

The content of the abrasive grains in the polishing composition is preferably 50% by mass or less, and more preferably 40% by mass or less. As the content of the abrasive grains is smaller, the manufacturing cost of the polishing composition is reduced, and in addition, it is easier to obtain a surface having less defects by polishing using the polishing composition. In addition, as the content of the abrasive grains is less, the residue of the abrasive grains on the polishing surface The amount of retention will be reduced, so the cleaning efficiency of the polished surface will be further improved.

The lower limit of the pH range of the polishing composition is 10.5 or more, preferably 11 or more, and more preferably 12 or more. The upper limit of the range of the pH of the polishing composition is not particularly limited, but is preferably less than 14. By setting the pH of the polishing composition to the above-described basic range, the polishing property of the object to be polished having the layer containing the cerium-containing material, specifically, the polishing rate can be further improved.

The pH of the polishing composition can be adjusted by adding a pH adjuster. As the pH adjuster, a well-known acid, a base, or a salt of these can be used.

Specific examples of the base which can be used as the pH adjuster include an alkali metal hydroxide or a salt thereof, an alkaline earth metal hydroxide and a salt thereof, a quaternary ammonium hydroxide compound, ammonia, an amine, and the like. Specific examples of the alkali metal include potassium, sodium, and the like. Specific examples of the salt include a carbonate, a hydrogencarbonate, a sulfate, an acetate, and the like. Specific examples of the quaternary ammonium include tetramethylammonium, tetraethylammonium, and tetrabutylammonium.

The quaternary ammonium hydroxide compound contains quaternary ammonium hydroxide or a salt thereof. Specific examples of the quaternary ammonium hydroxide include tetramethylammonium hydroxide, tetraethylammonium hydroxide, and tetrabutylammonium hydroxide.

Specific examples of the amine include methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, ethylenediamine, monoethanolamine, and N-(β-amino group. Ethyl)ethanolamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, piperazine anhydride, piperazine hexahydrate, 1-(2-aminoethyl)piperazine, N-methylpiperazine, hydrazine Wait. These bases can be used alone, Two or more types may be used in combination.

Among these bases, preferred are ammonium, ammonium salts, alkali metal hydroxides, alkali metal salts, quaternary ammonium hydroxide compounds, and amines. More preferably, ammonium, potassium compounds, sodium hydroxide, quaternary ammonium hydroxide compounds, ammonium hydrogencarbonate, ammonium carbonate, sodium hydrogencarbonate, and sodium carbonate can be used. The polishing composition is preferably a potassium compound as a base from the viewpoint of preventing metal contamination. Examples of the potassium compound include potassium hydroxide or a salt, and specific examples thereof include potassium hydroxide, potassium carbonate, potassium hydrogencarbonate, potassium sulfate, potassium acetate, and potassium chloride.

Specific examples of the acid which can be used as the pH adjuster include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid, or formic acid, acetic acid, and 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-methyl Hexanoic 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, horse Acid, phthalic acid, malic acid, tartaric acid, citric acid, lactic acid, diglycolic acid, 2-furancarboxylic acid, 2,5-furandicarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, An organic acid such as methoxyacetic acid, methoxyphenylacetic acid or phenoxyacetic acid. These acids may be used alone or in combination of two or more.

A salt such as an ammonium salt or an alkali metal salt may be substituted with the above acid or used in combination with the above acid.

The polishing composition used in the present embodiment can contain other additions as needed within a range that does not impair the effects of the present invention. Agent. Examples of other additives include an oxidizing agent, a chelating agent (a neutralizing agent), a water-soluble polymer, and a surfactant.

An oxidizing agent may also be included in the polishing composition. The oxidizing agent oxidizes the surface of the object to be polished to form an oxide film. Specific examples of the oxidizing agent include peroxide, periodic acid, periodate, permanganate, vanadate, hypochlorite, iron oxide, ozone, and the like. Specific examples of the peroxide include hydrogen peroxide, peracetic acid, percarbonate, urea peroxide and perchloric acid, perchlorate, and persulfate such as sodium persulfate, potassium persulfate and ammonium persulfate. Salt and so on. Among them, periodic acid, periodate, hypochlorite, persulfate and hydrogen peroxide are preferred from the viewpoint of polishing rate, and are excellent in terms of stability in an aqueous solution and environmental load. It is hydrogen peroxide. These oxidizing agents may be used alone or in combination of two or more.

The chelating agent functions to suppress metal contamination of the abrasive article by capturing metal impurities and forming a complex. Specific examples of the chelating agent include an aminocarboxylic acid-based chelating agent and an organic phosphonic acid-based chelating agent. Specific examples of the aminocarboxylic acid-based chelating agent include ethylenediaminetetraacetic acid, sodium ethylenediaminetetraacetate, nitrogen triacetic acid, sodium nitrilotriacetate, ammonium triacetate, and hydroxyethylethylene. Amine triacetic acid, sodium hydroxyethyl ethylenediamine triacetate, diamethylenetriamine pentaacetic acid, sodium diethylenediamine pentaacetate, triamethylenetetraamine hexaacetic acid, sodium triamethylenetetraacetate. Specific examples of the organic phosphonic acid-based chelating agent include 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotris(methylenephosphonic acid), and B. Diamine oxime (methylene phosphonic acid), diethylenetriamine penta (methylene phosphonic acid), triamethylenetetramine hexa Phosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, ethane-1-hydroxy-1,1-diphosphonic acid, ethane-1-hydroxyl -1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphonic acid, methane hydroxyphosphonic acid, 2-phosphonium butane-1,2-dicarboxylic acid, 1-phosphonium butane-2,3,4-tricarboxylic acid, α-methylphosphonium succinic acid, and the like. These chelating agents may be used alone or in combination of two or more.

A water-soluble polymer may be contained in the polishing composition. Specific examples of the water-soluble polymer include polystyrene sulfonate, polyisoprene sulfonate, polyacrylate, polymaleic acid, polyitaconic acid, polyvinyl acetate, and polyvinyl alcohol. , polyglycerol, polyvinylpyrrolidone, copolymer of isoprene sulfonic acid and acrylic acid, polyvinylpyrrolidone-polyacrylic acid copolymer, polyvinylpyrrolidone-vinyl acetate copolymer, naphthalene sulfonate a salt of an acid formaldehyde condensate, a diallylamine hydrochloride-sulphur dioxide copolymer, a carboxymethylcellulose, a salt of carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, amylopectin, Chitosan (chitosan), chitosan salts, and the like. In the case where the polishing composition is a water-soluble polymer, the surface roughness of the object to be polished after polishing using the polishing composition is further reduced. These water-soluble polymers may be used alone or in combination of two or more.

The content of the water-soluble polymer in the polishing composition is preferably 0.0001 g/L or more, and more preferably 0.001 g/L or more. As the content of the water-soluble polymer increases, the surface roughness of the polished surface obtained by using the polishing composition is further reduced.

The content of the water-soluble polymer in the polishing composition is Preferably, it is 10 g/L or less, more preferably 1 g/L or less. As the content of the water-soluble polymer is smaller, the residual amount of the water-soluble polymer on the polishing surface is reduced, so that the cleaning efficiency of the polished surface is further improved.

A surfactant may also be included in the polishing composition. The surfactant can improve the detergency after polishing by imparting hydrophilicity to the polishing surface, and can prevent dirt from adhering to the polishing surface or the like. The surfactant may be any of an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant.

In the specific examples of the anionic surfactant, polyoxyethylene alkyl ether acetic acid, polyoxyethylene alkyl sulfate, alkyl sulfate, polyoxyethylene alkyl sulfate, alkyl sulfuric acid, alkylbenzenesulfonic acid , alkyl phosphate, polyoxyethylene alkyl phosphate, polyoxyethylene sulfosuccinic acid, alkyl sulfosuccinic acid, alkyl naphthalenesulfonic acid, alkyl diphenyl ether disulfonic acid, such salts, etc. .

Specific examples of the cationic surfactant include an alkyltrimethylammonium salt, an alkyldimethylammonium salt, an alkylbenzyldimethylammonium salt, an alkylamine salt, and the like.

Specific examples of the amphoteric surfactant include alkylbetaine, alkylamine oxide and the like. 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, and poly An oxyethylene alkylamine, an alkyl alkanolamine or the like. These surfactants may be used alone or in combination of two or more.

The content of the surfactant in the polishing composition is preferably It is 0.0001 g/L or more, and more preferably 0.001 g/L or more. As the amount of surfactant is increased, the detergency after grinding is further enhanced.

The content of the surfactant in the polishing composition is preferably 10 g/L or less, more preferably 1 g/L or less. As the content of the surfactant is smaller, the residual amount of the surfactant on the polishing surface is reduced, so that the cleaning efficiency of the polished surface is further improved.

Next, the action of the polishing method using the polishing composition of the present embodiment and the polishing composition will be described.

The polishing method using the polishing composition of the present embodiment includes a method of polishing the object to be polished, for example, a substrate having a layer containing a ruthenium-containing material, using the above-described polishing composition. Thereby, the polishing property of the object to be polished, for example, the polishing speed can be further improved. The reason why the polishing property is excellent by using the polishing composition of the present embodiment is not clear, but it is presumed to be due to the following mechanism. Theoretically, the higher the pH of the environment surrounding the ruthenium-containing material, the more dissolved, and the higher the polishing rate. However, in the case where cerium oxide or cerium oxide is used as the abrasive grains, it is shown that if the pH is further increased, the abrasive grains themselves are dissolved, and the increase in the polishing rate of the surface of the cerium-containing material tends to be suppressed. However, it is presumed that according to the configuration of the polishing composition of the present embodiment, since the abrasive grains are not dissolved even in the high pH region, the surface of the cerium-containing material can be polished at a high speed.

Since the above mechanism is derived from speculation, the present invention is not limited to the above mechanism.

According to the polishing composition of the above embodiment, The effect described below is obtained.

(1) In the above embodiment, the polishing property of the object to be polished can be further improved. Specifically, in the case where the polishing target having the layer containing the ruthenium-containing material is polished by using the polishing composition of the present embodiment, a high polishing rate can be obtained.

The above embodiment is also modified as follows.

. The polishing composition of the above embodiment can also be prepared by diluting a stock solution of the polishing composition with water.

. A well-known additive such as an anticorrosive agent or an antifungal agent may be contained in the polishing composition as needed. Specific examples of the preservative and the antifungal agent include, for example, an isothiazoline compound, a paraben, a phenoxyethanol, and the like.

. A well-known additive such as a pH stabilizer may be contained in the polishing composition as needed. Examples of the pH stabilizer include a salt of a weak acid and a strong base, or a combination of a weak acid and a weak base.

. The polishing composition of the above embodiment may be used for polishing an object to be polished which does not have a layer containing a ruthenium-containing material.

[Examples]

Next, the present invention will be more specifically described by way of examples and comparative examples.

In each of the examples, a pH adjusting agent and water were added to the abrasive grains to prepare a polishing composition. Even in the same comparative examples, A polishing composition and a water are added to the abrasive grains to prepare a polishing composition. The details of the components in the polishing compositions of the examples and the comparative examples, and the pH measurement values of the respective polishing compositions of the examples and the comparative examples are shown in Table 1.

In the "polishing speed" column of Table 1, the ruthenium removal rate after polishing the surface of a 32 mm square single crystal Si substrate under the conditions shown in Table 2 using the polishing compositions of the examples and the comparative examples was shown. The value of the enthalpy removal rate was determined as follows. For each substrate, a precision balance was used to measure the mass before and after the polishing, and the difference between the measured values was determined. The obtained difference was converted into a volume based on the specific gravity (the value of 2.3 was used as the specific gravity of ruthenium). The thickness after polishing was determined from the volume and the area of the substrate, and the thickness after the polishing was divided by the polishing time (1 minute), and the obtained value was taken as the enthalpy removal rate.

As shown in Table 1, in each of the examples, a polishing rate which was practically satisfactory was obtained. On the other hand, in each of the comparative examples using the abrasive grains of ceria, titanium oxide or cerium oxide, the polishing rate which is practically satisfactory cannot be obtained.

Claims (4)

A polishing composition comprising at least one of abrasive grains and a pH adjuster selected from the group consisting of calcium carbonate, barium carbonate, and manganese dioxide, and having a pH of 12 or more (excluding 12), and used in A polishing object comprising a layer containing a bismuth material (excluding cerium carbide) for polishing. The polishing composition according to claim 1, wherein the cerium-containing material is at least one selected from the group consisting of elemental cerium, cerium oxide, and cerium nitride. A polishing method for polishing an object to be polished having a layer containing a cerium-containing material (excluding cerium carbide) by using the polishing composition according to claim 1 or 2. A method of producing a substrate comprising: a polishing step of polishing a substrate having a layer containing a ruthenium-containing material (excluding ruthenium carbide) by the polishing method of claim 3.