JP2021019112A - Composition for chemical mechanical polishing and manufacturing method and polishing method thereof - Google Patents

Abstract

To provide a composition for chemical mechanical polishing and polishing method using the same, capable of polishing a semiconductor substrate, particularly a semiconductor substrate with a portion containing ruthenium, at a high speed and capable of suppressing polishing damage of a surface to be polished.SOLUTION: The composition for chemical mechanical polishing contains (A) a titania particle containing aluminum and (B) a basic compound and pH is 7 or more to 13 or less.SELECTED DRAWING: None

Description

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

In general, the chemical mechanical polishing (hereinafter, also referred to as "CMP") method is used in the semiconductor manufacturing process, particularly in the flattening of the interlayer insulating film, the formation of the metal plug, and the formation of the embedded wiring (damer wiring) in the multilayer wiring forming process. It is being utilized. In such a semiconductor manufacturing process, in order to realize fine wiring having a circuit line width of 10 nm or less, a ruthenium film having low resistance and good compatibility with copper is currently used as a base of the copper film, and the copper film is embedded. Techniques for improving sex are being studied.

Since a ruthenium film is used, a ruthenium film polishing composition (slurry) for flattening by CMP has been studied (see, for example, Patent Documents 1 and 2).

Special Table 2009-514219 Special Table 2010-535424

Conventionally, in order to improve the polishing speed of the ruthenium film, it has been necessary to use abrasive grains having high hardness. However, in CMP using a composition for polishing a ruthenium film containing abrasive grains having high hardness, there is a problem that polishing scratches are likely to occur on the surface to be polished after polishing.

Therefore, in some aspects of the present invention, a composition for chemical mechanical polishing capable of high-speed polishing a semiconductor substrate, particularly a semiconductor substrate having a ruthenium-containing portion, and reducing polishing scratches on the surface to be polished, and a composition for polishing a chemical machine, To provide a polishing method using.

The present invention has been made to solve at least a part of the above-mentioned problems, and can be realized as any of the following aspects.

One aspect of the chemical mechanical polishing composition according to the present invention is
(A) Titania particles containing aluminum and
(B) Basic compounds and
The pH is 7 or more and 13 or less.

In one aspect of the chemical mechanical polishing composition,
Wherein _{(A) M} A [wt%] of the content of the component, the content of the component (B) is taken as _{M B [wt%],} the value of M A / _{M B} is 0.1 to 10 There can be.

In any aspect of the chemical mechanical polishing composition.
The content of the component (A) can be 0.1% by mass or more and 10% by mass or less with respect to the total mass of the composition for chemical mechanical polishing.

In any aspect of the chemical mechanical polishing composition.
Furthermore, (C) carboxylic acid can be contained.

In any aspect of the chemical mechanical polishing composition.
Furthermore, (D) an oxidizing agent can be contained.

One aspect of the method for producing a composition for chemical mechanical polishing according to the present invention is
It includes a step of adding (A) aluminum-containing titania particles and (B) a basic compound to a liquid medium.

One aspect of the polishing method according to the present invention is
The step of polishing a semiconductor substrate with the composition for chemical mechanical polishing according to any one of the above is included.

In one aspect of the polishing method,
The semiconductor substrate can include a portion containing ruthenium.

According to the composition for chemical mechanical polishing according to the present invention, a semiconductor substrate, particularly a semiconductor substrate having a ruthenium-containing portion, can be polished at high speed, and polishing scratches on the surface to be polished can be reduced. Further, according to the polishing method according to the present invention, by using the above-mentioned chemical mechanical polishing composition, a semiconductor substrate, particularly a semiconductor substrate having a ruthenium-containing portion, is polished at high speed, and a surface to be polished with few polishing scratches is obtained. Can be manufactured.

(A) is a conceptual diagram schematically showing a major axis (Rmax) and a minor axis (Rmin) of aluminum-containing titania particles. It is sectional drawing which shows typically the object to be processed suitable for use of the polishing method which concerns on this embodiment. It is sectional drawing which shows typically the object to be processed at the time of completion of the 1st polishing process. It is sectional drawing which shows typically the object to be processed at the time of completion of the 2nd polishing process. It is a perspective view which shows typically the chemical mechanical polishing apparatus.

Hereinafter, preferred embodiments of the present invention will be described in detail. The present invention is not limited to the following embodiments, and includes various modifications that are carried out without changing the gist of the present invention.

In the present specification, the numerical range described by using "~" means that the numerical values described before and after "~" are included as the lower limit value and the upper limit value.

1. 1. Composition for Chemical Mechanical Polishing The composition for chemical mechanical polishing according to an embodiment of the present invention contains (A) aluminum-containing titania particles and (B) basic compound, and has a pH of 7 or more and 13 or less. Is. Hereinafter, each component contained in the chemical mechanical polishing composition according to the present embodiment will be described in detail.

1.1. (A) Aluminum-containing titania particles The composition for chemical mechanical polishing according to the present embodiment contains (A) aluminum-containing titania particles (also simply referred to as "component (A)" in the present specification). To do. Examples of the "aluminum-containing titania particles" include an embodiment in which at least a part of the surface of the titania particles is coated with a material containing an aluminum element.

In such a component (A), in the pH range of 7 or more and 13 or less, the absolute value of the zeta potential becomes larger than that of the titania particles containing no aluminum, and the electrostatic repulsive force between the particles increases. , It is considered that the dispersibility of particles in the composition for chemical mechanical polishing is improved. As a result, the semiconductor substrate having the ruthenium-containing portion can be polished at high speed, and the polishing scratches on the surface to be polished can be reduced.

In addition, titania particles easily react with water, oxygen, nitrogen, etc., and tend to deteriorate over time. However, when at least a part of the surface of the titania particles is coated with a material containing an aluminum element like the component (A), the reactivity with water, oxygen, nitrogen, etc. on the surface of the titania particles is reduced. Therefore, deterioration over time can be suppressed.

For the component (A), the upper limit of the full width at half maximum of the peak portion where the diffraction intensity in the powder X-ray diffraction pattern is maximum is preferably less than 1 °, and more preferably less than 0.7 °. The lower limit of the half width is preferably 0.2 ° or more. When the full width at half maximum of the peak portion where the diffraction intensity is maximized is within the above range, the crystallites of the component (A) become homogeneous and have the optimum hardness for polishing. As a result, the semiconductor substrate provided with the ruthenium-containing portion can be polished at high speed, and the polishing scratches on the surface to be polished can be reduced.

The powder X-ray diffraction pattern is a diffraction measured at each incident angle in a two-dimensional graph having an incident angle on the horizontal axis and a diffraction intensity on the vertical axis when a sample is measured by powder X-ray diffraction. Refers to the intensity plot line.

In the component (A) in the present embodiment, when the major axis of the component (A) is Rmax and the minor axis is Rmin, the lower limit of the ratio (Rmax / Rmin) between the major axis and the minor axis is preferably 1.1. Yes, more preferably 1.5, and particularly preferably 2.0. The upper limit of the ratio of the major axis to the minor axis (Rmax / Rmin) is preferably 4.0, more preferably 3.8, and particularly preferably 3.5. When the ratio of the major axis to the minor axis (Rmax / Rmin) is 1.1 or more, the semiconductor substrate having the ruthenium-containing portion can be polished at high speed, and the ratio of the major axis to the minor axis (Rmax / Rmin) is 4. When it is 0.0 or less, it is possible to suppress the catching of the component (A) at the end portion, so that it is possible to reduce the polishing scratches on the surface to be polished of the semiconductor substrate provided with the ruthenium-containing portion.

The ratio (Rmax / Rmin) of the major axis to the minor axis of the component (A) can be adjusted by appropriately controlling the heat treatment conditions, acid addition conditions, pulverization conditions, etc. in manufacturing.

The major axis (Rmax) and minor axis (Rmin) of the component (A) can be measured as follows. For example, when the image of one independent particle 1 taken by a transmission electron microscope as shown in FIG. 1 has an elliptical shape, the major axis a of the elliptical shape is determined to be the major axis (Rmax) of the particle 1, and the ellipse. The minor axis b of the shape is determined to be the minor axis (Rmin) of the particle 1. By such a discrimination method, for example, the major axis (Rmax) and the minor axis (Rmin) of 50 particles are measured, the average value of the major axis (Rmax) and the minor axis (Rmin) is calculated, and then the major axis and the minor axis are determined. The ratio (Rmax / Rmin) of can be calculated and obtained.

(A) component contains, the number of moles of _{M Ti} of titanium, the molar number of the aluminum is taken as _{M Al,} the lower limit value of M Ti _{/ M Al} is preferably 6, more preferably 10 Yes, especially preferably 20. The upper limit of the value of M _Ti / M _Al is preferably 70, more preferably 65, and particularly preferably 60. If the value of M _Ti / M _Al of the component (A) is within the above range, the component (A) can maintain sufficient hardness even when polishing a hard material. Therefore, the semiconductor substrate provided with the ruthenium-containing portion can be polished at high speed. Further, when the value of M _Ti / M _Al is within the above range, aggregation can be suppressed by the electrostatic repulsive force between the particles, and the enlargement of the particles can be effectively suppressed. As a result, polishing scratches on the surface to be polished can be further reduced.

The value of M _Ti / M _Al of the component (A) is determined by dissolving the component (A) with dilute hydrofluoric acid and ICP-MS (inductively coupled plasma mass spectrometer: manufactured by PerkinElmer, for example, model number "ELAN DRC PLUS". ), The contents of titanium and aluminum can be measured and calculated from the measured values.

The absolute value of the zeta potential of the component (A) is preferably 25 mV or more, more preferably 30 mV or more, and particularly preferably 35 mV or more. When the absolute value of the zeta potential of the component (A) is within the above range, the electrostatic repulsive force between the components (A) increases, so that the dispersibility of the component (A) in the composition for chemical mechanical polishing is improved. To do. As a result, the semiconductor substrate having the ruthenium-containing portion can be polished at high speed, and the polishing scratches on the surface to be polished can be reduced. The zeta potential of the component (A) can be measured by a conventional method using a zeta potential measuring device based on the laser Doppler method. Examples of such a zeta potential measuring device include a "zeta potential analyzer" manufactured by Brook Haven Instruments Co., Ltd. and an "ELSZ-1000ZS" manufactured by Otsuka Electronics Co., Ltd.

The lower limit of the average particle size of the component (A) is preferably 10 nm, more preferably 20 nm. The upper limit of the average particle size of the component (A) is preferably 300 nm, more preferably 200 nm. When the average particle size of the component (A) is within the above range, a sufficient polishing rate can be obtained, and a composition for chemical mechanical polishing having excellent stability without causing precipitation or separation of particles can be obtained. The average particle size of the component (A) is determined by, for example, a fluidized specific surface area automatic measuring device (“micrometricsFlowSorbII2300” manufactured by Shimadzu Corporation) for a sample obtained by drying the composition containing the component (A). The specific surface area by the BET method can be measured using the above and calculated from the measured value.

The method for producing the component (A) is not particularly limited, but for example, an oxide raw material solution containing at least the raw material of the component (A) and an oxide precipitation containing at least an oxide-precipitating substance for precipitating the component (A). A method of producing oxide particles by a known method such as reaction, crystallization, precipitation, and co-precipitation in a mixed fluid in which a solvent is prepared and an oxide raw material solution and an oxide precipitation solvent are mixed is used. be able to. Further, aluminum and titanium contained in the component (A) may be contained together in the oxide raw material solution, may be contained in the oxide raw material solution and the oxide precipitation solvent, respectively, and may be contained in the oxide raw material solution. It may be contained in both the liquid and the oxide precipitation solvent.

Further, the component (A) in the embodiment in which at least a part of the surface of the titania particles is coated with a material containing an aluminum element can be prepared by the following method using the titania particles as a raw material.

First, the titania particles are dispersed in water to form a slurry. Next, an aqueous aluminum salt solution dissolved in water such as an aqueous solution of sodium aluminate, an aqueous solution of aluminum sulfate, and an aqueous solution of aluminum chloride was added so that the amount was preferably 1 to 50 parts by mass in terms of alumina with respect to 100 parts by mass of titania particles. At the same time, an acid such as sulfuric acid, hydrochloric acid, or nitrate, or a base such as an aqueous sodium hydroxide solution or aqueous ammonia is added to maintain this slurry at pH 5 to 8. By this operation, the surface of the titania particles is coated with alumina. After that, homogeneous particles can be produced by known methods such as filtration, washing, drying, and pulverization.

As the titania particles used in the above production method, any of rutile type, anatase type, amorphous type and a mixture thereof can be used, but rutile type is preferable.

The lower limit of the content of the component (A) (M _A), based on the total mass of the chemical mechanical polishing composition is preferably 0.1 wt%, more preferably from 0.3 mass%, particularly It is preferably 0.5% by mass. The upper limit of the amount of the component (A) _{(M A)} is preferably from 10.0 mass%, more preferably from 5.0% by weight, particularly preferably 3.0% by mass.

1.2. (B) Basic Compound The composition for chemical mechanical polishing according to the present embodiment contains (B) a basic compound (also simply referred to as “component (B)” in the present specification). By containing the basic compound (B), the dispersion stability of the component (A) can be enhanced. As a result, the aggregation of the component (A) can be suppressed, the generation of coarse particles can be suppressed, and the occurrence of polishing scratches can be effectively reduced.

Examples of the (B) basic compound include organic bases and inorganic bases, and organic bases are preferable. As the organic base, amines are preferable, and examples thereof include triethylamine, monoethanolamine, benzylamine, methylamine, ethylenediamine, diglycolamine, isopropylamine, dodecylaminoethylaminoethylglycine and the like. Examples of the inorganic base include ammonia, potassium hydroxide, sodium hydroxide and the like. Among these inorganic bases, ammonia, potassium hydroxide and monoethanolamine are preferable. As the basic compound (B), the above-exemplified compounds may be used alone or in combination of two or more.

The lower limit of the content of the component (B) _{(M B),} based on the total mass of the chemical mechanical polishing composition is preferably 0.01 mass%, more preferably 0.1% by mass. The upper limit of the content of the component (B) _{(M B)} is preferably from 1.5 mass%, more preferably 1.3% by mass.

In the chemical mechanical polishing composition of this embodiment, when the _(A) M A _[wt%] of the content of the component and (B) the content of the component M _{B [wt%],} M _A / it is preferable that the value of M _B is in the range of 0.1 to 10, and more preferably in the range of 0.5 to 5. When the value of M A _/ M _B is within the above range, the polishing rate of the ruthenium film, is excellent in balance between polishing scratches suppressed with respect to the insulating film of the silica film and the like, so as to coexist and ruthenium film and the insulating film When polishing the surface to be polished, it is easy to obtain a surface to be polished having excellent smoothness and few polishing defects.

1.3. (C) Carboxylic Acid The composition for chemical mechanical polishing according to the present embodiment preferably further contains (C) carboxylic acid (also simply referred to as “component (C)” in the present specification). By containing the component (C), when polishing the surface to be polished such that the ruthenium film and the insulating film coexist, it may be possible to polish at a higher speed.

"Carboxylic acid" refers to a compound having a carboxyl group (-COOH).

The component (C) is not particularly limited, but is, for example, stearic acid, lauric acid, oleic acid, myristic acid, dodecylbenzenesulfonic acid, alkenylsuccinic acid, lactic acid, tartaric acid, fumaric acid, glycolic acid, phthalic acid, maleic acid. , Formic acid, acetic acid, oxalic acid, citric acid, malic acid, malonic acid, glutaric acid, succinic acid, benzoic acid, quinophosphate, quinaldic acid, amidosulfate, propionic acid, trifluoroacetic acid, p-toluenesulfonic acid, glycine, Examples thereof include amino acids such as alanine, aspartic acid, glutamic acid, lysine, arginine, tryptophan, aromatic amino acids and heterocyclic amino acids, and carboxylic acid polymers such as polyacrylic acid and polymethacrylic acid. These components (C) may be used alone or in combination of two or more.

The lower limit of the content of the component (C) _{(M C),} based on the total mass of the chemical mechanical polishing composition is preferably 0.01 mass%, more preferably 0.1% by mass. The upper limit of the content of the component (C) (M _C) is preferably 5 wt%, more preferably from 2 mass%.

In the chemical mechanical polishing composition of this embodiment, when the _(A) M A _[wt%] of the content of the component and (C) the content of the component M _{C [wt%],} M _A / it is preferable that the value of M _C is in the range of 0.1 to 30, and more preferably in the range of 0.4 to 25. When the value of M A _/ M _C is within the above range, the interaction of the component (A) to the component (C) was polished faster polished surface so as to coexist and ruthenium film and the insulating film It becomes easy to obtain a surface to be polished with excellent smoothness.

1.4. (D) Oxidizing Agent The chemical mechanical polishing composition according to the present embodiment preferably contains (D) an oxidizing agent (also simply referred to as "component (D)" in the present specification). (D) By containing an oxidizing agent, a metal such as ruthenium is oxidized to promote a complexing reaction with a polishing liquid component, so that a fragile modified layer can be created on the surface to be polished. It has the effect of making it easier.

Examples of the oxidizing agent include ammonium persulfate, potassium persulfate, hydrogen peroxide, ferric nitrate, cerium diammonium nitrate, potassium hypochlorite, sodium hypochlorite, ozone, and potassium periodate. Peracetic acid and the like can be mentioned. Among these oxidizing agents, at least one selected from potassium periodate, potassium hypochlorite, and hydrogen peroxide is preferable, and hydrogen peroxide is more preferable, from the viewpoint of suppressing the generation of ruthenium tetroxide. These (D) oxidizing agents may be used alone or in combination of two or more.

When the composition for chemical mechanical polishing according to the present embodiment contains (D) an oxidizing agent, the lower limit of the content of the component (D) is preferably 0 with respect to the total mass of the composition for chemical mechanical polishing. It is 001% by mass, more preferably 0.005% by mass. The upper limit of the content of the component (D) is preferably 5% by mass, more preferably 3% by mass.

1.5. Other Additives The composition for chemical mechanical polishing according to the present embodiment includes water as a main liquid medium, an inorganic acid, an organic acid other than the component (C), and a nitrogen-containing heterocyclic compound, if necessary. It may contain a surfactant, a water-soluble polymer and the like.

<Water>
The chemical mechanical polishing composition according to this embodiment contains water as a main liquid medium. The water is not particularly limited, but pure water is preferable as the raw material. Water may be blended as the remainder of the constituent material of the above-mentioned chemical mechanical polishing composition, and the content of water is not particularly limited.

<Inorganic acid>
The composition for chemical mechanical polishing according to the present embodiment may contain an inorganic acid. By containing an inorganic acid, the polishing rate for a metal film such as a ruthenium film may be further improved.

As the inorganic acid, for example, at least one selected from hydrochloric acid, nitric acid, sulfuric acid, and phosphoric acid is preferable. The inorganic acid may form a salt with a base separately added in the composition for chemical mechanical polishing.

When the inorganic acid is contained, the content of the inorganic acid is preferably 0.01 to 1.5% by mass, more preferably 0.1 to 1. 1% by mass, based on the total mass of the composition for chemical mechanical polishing. It is 0% by mass.

<Organic acids other than component (C)>
The composition for chemical mechanical polishing according to the present embodiment may contain an organic acid other than the component (C). By containing such an organic acid, the polishing rate for a metal film such as a ruthenium film may be further improved.

Examples of the organic acid other than the component (C) include dodecylbenzenesulfonic acid, p-toluenesulfonic acid, amidosulfate and the like. The organic acid other than the component (C) may form a salt with a base separately added in the composition for chemical mechanical polishing.

When an organic acid other than the component (C) is contained, the content of the inorganic acid is preferably 0.01 to 1.5% by mass, more preferably 0.01 to 1.5% by mass, based on the total mass of the composition for chemical mechanical polishing. It is 0.1 to 1.0% by mass.

<Nitrogen-containing heterocyclic compound>
The composition for chemical mechanical polishing according to the present embodiment may contain a nitrogen-containing heterocyclic compound. By containing the nitrogen-containing heterocyclic compound, it may be possible to suppress excessive etching of a metal such as ruthenium and prevent surface roughness after polishing.

A nitrogen-containing heterocyclic compound is an organic compound having at least one nitrogen atom and containing at least one heterocycle selected from a hetero5-membered ring and a hetero6-membered ring. Examples of the heterocycle include a complex five-membered ring such as a pyrrole structure, an imidazole structure, and a triazole structure; and a complex six-membered ring such as a pyridine structure, a pyrimidine structure, a pyridazine structure, and a pyrazine structure. The heterocycle may form a fused ring. Specific examples thereof include an indole structure, an isoindole structure, a benzimidazole structure, a benzotriazole structure, a quinoline structure, an isoquinoline structure, a quinazoline structure, a cinnoline structure, a phthalazine structure, a quinoxaline structure, and an acridin structure. Among the heterocyclic compounds having such a structure, a heterocyclic compound having a pyridine structure, a quinoline structure, a benzimidazole structure, and a benzotriazole structure is preferable.

Specific examples of the nitrogen-containing heterocyclic compound include aziridine, pyridine, pyrimidine, pyrrolidine, piperidine, pyrazine, triazine, pyrrole, imidazole, indol, quinoline, isoquinoline, benzoisoquinoline, purine, pteridine, triazole, triazotriazole, benzotriazole, and carboxy. Examples thereof include benzotriazole and the like, and further examples thereof include derivatives having these skeletons. Among these, at least one selected from benzotriazole and triazole is preferable. These nitrogen-containing heterocyclic compounds may be used alone or in combination of two or more.

When the nitrogen-containing heterocyclic compound is contained, the content of the nitrogen-containing heterocyclic compound is preferably 0.05 to 2% by mass, more preferably 0.% by mass, based on the total mass of the composition for chemical mechanical polishing. It is 1 to 1% by mass.

<Surfactant>
The composition for chemical mechanical polishing according to the present embodiment may contain a surfactant. Surfactants have the effect of imparting appropriate viscosity to the composition for chemical mechanical polishing, suppress excessive etching of metals such as ruthenium, and prevent surface roughness after polishing such as corrosion. You may be able to do it.

The surfactant is not particularly limited, and examples thereof include an anionic surfactant, a cationic surfactant, and a nonionic surfactant. Examples of the anionic surfactant include carboxylic acid salts such as fatty acid soap and alkyl ether carboxylate; sulfonates such as alkylbenzene sulfonate, alkylnaphthalene sulfonate and α-olefin sulfonate; higher alcohol sulfate. Sulfates such as ester salts, alkyl ether sulfates and polyoxyethylene alkylphenyl ether sulfates; fluorine-containing surfactants such as perfluoroalkyl compounds can be mentioned. Examples of the cationic surfactant include an aliphatic amine salt and an aliphatic ammonium salt. Examples of the nonionic surfactant include a nonionic surfactant having a triple bond such as acetylene glycol, an acetylene glycol ethylene oxide adduct, and an acetylene alcohol; a polyethylene glycol type surfactant and the like. These surfactants may be used alone or in combination of two or more.

When a surfactant is contained, the content of the surfactant is preferably 0.001 to 5% by mass, more preferably 0.001 to 3% by mass, based on the total mass of the composition for chemical mechanical polishing. %, Especially preferably 0.01 to 1% by mass.

<Water-soluble polymer>
The composition for chemical mechanical polishing according to the present embodiment may contain a water-soluble polymer (excluding a carboxylic acid polymer). Examples of such a water-soluble polymer include polyacrylamide, polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, polyethyleneimine, polyvinylmethyl ether, polyallylamine, hydroxyethyl cellulose, cyclodextrin and the like.

The weight average molecular weight (Mw) of the water-soluble polymer is preferably 1,000 or more and 1,500,000 or less, more preferably 10,000 or more and 500,000 or less, and particularly preferably 30,000 or more and 100. It is less than 000. The "weight average molecular weight (Mw)" in the present specification refers to a polyethylene glycol-equivalent weight average molecular weight measured by GPC (gel permeation chromatography).

When a water-soluble polymer is contained, the content of the water-soluble polymer is preferably added so that the viscosity of the composition for chemical mechanical polishing is less than 10 mPa · s. For example, the composition for chemical mechanical polishing. It is preferably 0.001 to 1% by mass, more preferably 0.003 to 0.5% by mass, based on the total mass of the above.

1.6. pH
The pH of the chemical mechanical polishing composition according to the present embodiment is 7 to 13, but is preferably 8 to 12.5. When the pH is 7 or more, the absolute value of the zeta potential of the component (A) in the chemical mechanical polishing composition becomes large and the dispersibility is improved. Therefore, polishing scratches on the semiconductor substrate provided with the ruthenium-containing portion Can be polished at high speed while reducing the amount of water. On the other hand, when the pH is less than 7, the absolute value of the zeta potential of the component (A) in the composition for chemical mechanical polishing becomes small, the dispersibility deteriorates and agglutination occurs, so that the polishing rate decreases and polishing defects occur. Is likely to occur.

The pH of the chemical mechanical polishing composition according to the present embodiment can be adjusted by appropriately increasing or decreasing the amount of the above-mentioned component (B), component (C), inorganic acid, and organic acid.

In the present invention, pH refers to a hydrogen ion index, and the value can be measured using a commercially available pH meter (for example, a tabletop pH meter manufactured by HORIBA, Ltd.).

1.7. Applications The chemical mechanical polishing composition according to the present embodiment can polish a semiconductor substrate provided with a ruthenium-containing portion at high speed as described above, and can reduce polishing scratches on the surface to be polished. In particular, the composition for chemical mechanical polishing according to the present embodiment is suitable as a polishing material for chemical mechanical polishing of a ruthenium film-containing substrate in a semiconductor substrate in which a ruthenium film, which is a next-generation semiconductor material, is applied as a base of a copper film. Is.

1.8. Method for Producing Composition for Chemical Mechanical Polishing In the method for producing a composition for chemical mechanical polishing according to an embodiment of the present invention, (A) aluminum-containing titania particles and (B) a basic compound are used as a liquid medium. Including the step of adding to. If the pH of the chemical mechanical polishing composition obtained by this step is not in the range of 7 to 13, or if the pH of the chemical mechanical polishing composition is in the range of 7 to 13, the pH should be further adjusted. In some cases, the step of adjusting the pH by adding the component (B), the component (C), and other additives may be further performed.

The composition for chemical mechanical polishing described above can be prepared by adding the component (A), the component (B), and other components as necessary to a liquid medium to dissolve or disperse the composition. The method for dissolving or dispersing each component in the liquid medium is not particularly limited, and any method may be applied as long as it can be uniformly dissolved or dispersed. Further, the mixing order and mixing method of each component described above are not particularly limited.

The composition for chemical mechanical polishing thus obtained can be prepared as a concentrated type stock solution and diluted with a liquid medium such as water at the time of use.

2. 2. Polishing method
The polishing method according to the embodiment of the present invention includes a step of polishing a semiconductor substrate by using the above-mentioned chemical mechanical polishing composition. The composition for chemical mechanical polishing described above can polish a semiconductor substrate provided with a ruthenium-containing portion at high speed, and can reduce polishing scratches on the surface to be polished. In particular, the polishing method according to the present embodiment is suitable for polishing a semiconductor substrate on which a ruthenium film, which is a next-generation semiconductor material, is applied as a base of a copper film. Hereinafter, a specific example of the polishing method according to the present embodiment will be described in detail with reference to the drawings.

2.1. The object to be processed FIG. 2 is a cross-sectional view schematically showing an object to be processed suitable for use in the polishing method according to the present embodiment. The object to be processed 100 is formed by going through the following steps (1) to (4).

(1) First, as shown in FIG. 2, the substrate 10 is prepared. The substrate 10 may be composed of, for example, a silicon substrate and a silicon oxide film formed on the silicon substrate. Further, a functional device such as a transistor (not shown) may be formed on the substrate 10. Next, a silicon oxide film 12 which is an insulating film is formed on the substrate 10 by a thermal oxidation method.

(2) Next, the silicon oxide film 12 is patterned. Using the obtained pattern as a mask, a wiring groove 14 is formed in the silicon oxide film 12 by a photolithography method.

(3) Next, the ruthenium film 16 is formed on the surface of the silicon oxide film 12 and the inner wall surface of the wiring groove 14. The ruthenium film 16 is formed by, for example, a chemical vapor deposition method (CVD) or an atomic layer deposition method (ALD) using a ruthenium precursor, or a physical vapor phase deposition method (P) such as sputtering.
It can be formed by VD).

(4) Next, a copper film 18 of 10,000 to 15,000 Å is deposited by a chemical vapor deposition method or an electroplating method. As the material of the copper film 18, not only high-purity copper but also an alloy containing copper can be used. The copper content in the copper-containing alloy is preferably 95% by mass or more.

2.2. Polishing method 2.2.1. First Polishing Step FIG. 3 is a cross-sectional view schematically showing an object to be processed 100 at the end of the first polishing step. As shown in FIG. 3, the first polishing step is a step of polishing the copper film 18 using a chemical mechanical polishing composition for a copper film until the ruthenium film 16 is exposed.

2.2.2. The second polishing step FIG. 4 is a cross-sectional view schematically showing the object to be processed 100 at the end of the second polishing step. As shown in FIG. 4, the second polishing step is a step of polishing the silicon oxide film 12, the ruthenium film 16, and the copper film 18 using the above-mentioned chemical mechanical polishing composition. Since the above-mentioned composition for chemical mechanical polishing is used in the second polishing step, the semiconductor substrate provided with the ruthenium-containing portion can be polished at high speed, and polishing scratches on the surface to be polished can be reduced.

2.3. Chemical mechanical polishing apparatus For the first polishing step and the second polishing step described above, for example, the polishing apparatus 200 as shown in FIG. 5 can be used. FIG. 5 is a perspective view schematically showing the polishing apparatus 200. In the first polishing step and the second polishing step described above, the semiconductor substrate is supplied with the slurry (composition for chemical mechanical polishing) 44 from the slurry supply nozzle 42, and the turntable 48 to which the polishing pad 46 is attached is rotated. This is performed by bringing the carrier head 52 holding the 50 into contact with the carrier head 52. Note that FIG. 5 also shows the water supply nozzle 54 and the dresser 56.

The polishing load of the carrier head 52 can be selected in the range of 0.7 to 70 psi, preferably 1.5 to 35 psi. The rotation speed of the turntable 48 and the carrier head 52 can be appropriately selected within the range of 10 to 400 rpm, and is preferably 30 to 150 rpm. The flow rate of the slurry (composition for chemical mechanical polishing) 44 supplied from the slurry supply nozzle 42 can be selected within the range of 10 to 1,000 mL / min, and is preferably 50 to 400 mL / min.

Examples of commercially available polishing equipment include, for example, Ebara Corporation, model "EPO-112", "EPO-222"; Lapmaster SFT, model "LGP-510", "LGP-552"; Applied Materials. , Model "Mirra", "Reflection"; G & P
TECHNOLOGY, model "POLI-400L"; AMAT, model "Reflection LK" and the like.

3. 3. Examples The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples. In addition, "part" and "%" in this Example are based on mass unless otherwise specified.

3.1. Abrasive grain preparation <Preparation of titania particles A>
A 48% sodium hydroxide aqueous solution was added to 35 kg (10 kg in terms of TIO ₂ ) of a hydrous titanium dioxide cake (titanium dioxide hydrate) that had been filtered and washed by hydrolyzing the titanyl sulfate solution by a conventional method with stirring. It was heated and stirred in a temperature range of 95 to 105 ° C. for 2 hours. The slurry was then filtered and washed thoroughly to give a base-treated titanium dioxide hydrate. Water was added to this hydrate cake to form a slurry, and the concentration was adjusted to 110 g / L in terms of TiO ₂ . While stirring this slurry, 35% hydrochloric acid was added to adjust the pH to 7.0.

Next, the slurry was heated to 50 ° C., and 12.5 kg of 35% hydrochloric acid was added at this temperature for 4 minutes with stirring, and the hydrochloric acid concentration in the slurry after addition of hydrochloric acid was 40 g / L in terms of 100% HCl. It was made to become. The hydrochloric acid addition rate was 0.11 kg / min per 1 kg of TiO ₂ . Following the addition of hydrochloric acid, the slurry was heated and aged at 100 ° C. for 2 hours. Ammonia water was added to the aging slurry to neutralize it to pH = 6.5. Then, it was filtered and washed with water, dried and then pulverized to obtain titania particles A.

<Preparation of aluminum-containing titania particles B to F>
The powder obtained by mixing the titania particles A and aluminum hydroxide obtained above was calcined in the range of 100 to 1000 ° C., and then washed with a 1% aqueous sodium hydroxide solution. Then, it was washed with water, dried and pulverized to obtain aluminum-containing titania particles. At this time, the aluminum-containing titania particles B to F shown in Tables 1 to 2 are obtained by appropriately adjusting the mixing ratio of the titania particles A and aluminum hydroxide and appropriately changing the firing temperature within the range of 100 to 1000 ° C. I got each.

<Preparation of aluminum-containing titania particles G>
A 48% sodium hydroxide aqueous solution was added to 35 kg (10 kg in terms of TIO ₂ ) of a hydrous titanium dioxide cake (titanium dioxide hydrate) that had been filtered and washed by hydrolyzing the titanyl sulfate solution by a conventional method with stirring. It was heated and stirred in a temperature range of 95 to 105 ° C. for 2 hours. The slurry was then filtered and washed thoroughly to give base-treated titania particles. The obtained powder obtained by mixing the titania particles and aluminum hydroxide was calcined in the range of 100 to 1000 ° C., and then washed with a 1% aqueous sodium hydroxide solution. Then, it was washed with water, dried and pulverized to obtain aluminum-containing titania particles. At this time, the mixing ratio of the titania particles and aluminum hydroxide was appropriately adjusted, and the firing temperature was appropriately changed within the range of 100 to 1000 ° C. to obtain the aluminum-containing titania particles G shown in Table 2.

<Silica particles>
As the silica particles, PL-3L manufactured by Fuso Chemical Industry Co., Ltd. was used.

<Alumina particles>
As the alumina particles, Advanced Alumina Series AA-04 manufactured by Sumitomo Chemical Co., Ltd. was used.

3.2. Evaluation of physical properties of abrasive grains 3.2.1. Measurement of X-ray Diffraction Intensity of Abrasive Grains The half width of the peak portion where the diffraction intensity of the powder X-ray diffraction pattern of the abrasive grains obtained above is maximized was measured under the following conditions.
(Measurement condition)
-Device: Fully automatic horizontal multipurpose X-ray diffractometer SmartLab (manufactured by Rigaku)
・ X-ray source: 3 kW (water cooling)
-Measurement method: Powder method using a glass sample plate-Slit: PB medium resolution-Measurement range: 15-120 deg
-Step: 0.05 deg
-Scan speed: 0.5 deg / min (continuous)

3.2.2. Ti / Al molar ratio analysis of aluminum-containing titania particles The aluminum-containing titania particles obtained above are dissolved in dilute hydrofluoric acid and titanium is used by ICP-MS (Perkin Elmer, model number "ELAN DRC PLUS"). The contents of (Ti) and aluminum (Al) were measured, and the molar ratio (M _Ti / M _Al ) was calculated.

3.2.3. Measurement of major axis (Rmax) and minor axis (Rmin) of abrasive grains The abrasive grains obtained above were dried and observed with a transmission electron microscope. The major axis (Rmax) and minor axis (Rmin) of 50 abrasive grains are measured by the judgment method shown above, the average value of the major axis (Rmax) and minor axis (Rmin) is calculated, and then the major axis and minor axis are calculated. The ratio (Rmax / Rmin) with and was calculated and obtained.

3.3. Preparation of Composition for Chemical Mechanical Polishing A predetermined amount of the abrasive grains prepared above is added to a polyethylene bottle having a capacity of 1 L, and then each component is added so as to have the compositions shown in Tables 1 and 2, and further. If necessary, ammonia was added to adjust the pH to the pH shown in Tables 1 and 2, and the pH was adjusted to 100 parts by mass so that the total amount of all the components was 100 parts by mass. An example chemical mechanical polishing composition was prepared.

3.4. Evaluation method 3.4.1. Polishing Speed Evaluation Using the composition for chemical mechanical polishing obtained above, a chemical mechanical polishing test was carried out for 30 seconds under the following polishing conditions using a wafer with a ruthenium film of 8 inches in diameter having a ruthenium film of 50 nm as an object to be polished.

<Polishing conditions>
-Polishing equipment: G & P TECHNOLOGY, model "POLI-400L"
-Polishing pad: "Multi-hard polyurethane pad; H800-type1 (3-1S) 775" manufactured by Fuji Spinning Co., Ltd.
・ Composition supply speed for chemical mechanical polishing: 100 mL / min ・ Surface plate rotation speed: 100 rpm
・ Head rotation speed: 90 rpm
・ Head pressing pressure: 2psi
・ Polishing speed (Å / min) = (thickness of film before polishing-thickness of film after polishing) / polishing time

The thickness of the ruthenium film is measured by the DC4 probe method using a resistivity measuring machine (manufactured by NPS, model "Σ-5"), and the following formula is used from the sheet resistance value and the volume resistivity of ruthenium. Calculated by
Film thickness (Å) = [Volume resistivity of ruthenium film (Ω ・ m) ÷ Sheet resistance value (Ω)] × 10 ¹⁰

The evaluation criteria for polishing speed are as follows. The polishing rate of the ruthenium film and its evaluation results are also shown in Tables 1 and 2.
(Evaluation criteria)
-When the polishing speed is 350 Å / min or more, the polishing time can be significantly shortened in actual semiconductor polishing, so it is judged to be very good.
-When the polishing speed is 300 Å / min or more and less than 350 Å / min, it is judged to be good because the speed balance with the polishing of other material films can be easily secured in the actual semiconductor polishing and it can be put into practical use.
-If the polishing rate is less than 300 Å / min, the polishing rate is low and it is difficult to put it into practical use, so it is judged to be defective.

3.4.2. Defect Evaluation A wafer with a silicon oxide film having a diameter of 12 inches, which is the object to be polished, was polished for 1 minute under the following conditions.
<Polishing conditions>
-Abrading device: AMAT, model "Reflection LK"
-Polishing pad: "Multi-hard polyurethane pad; H800-type1 (3-1S) 775" manufactured by Fuji Spinning Co., Ltd.
-Chemical mechanical polishing composition supply speed: 300 mL / min-Surface plate rotation speed: 100 rpm
・ Head rotation speed: 90 rpm
・ Head pressing pressure: 2psi

With respect to the wafer with the silicon oxide film polished above, the total number of defects having a size of 90 nm or more was counted using a defect inspection device (manufactured by KLA Tencor Co., Ltd., model “Surfscan SP1”). The evaluation criteria are as follows. The total number of defects per wafer and the evaluation results thereof are also shown in Tables 1 and 2.
(Evaluation criteria)
-If the total number of defects per wafer is less than 200, it is judged to be very good because the yield of non-defective semiconductors is significantly improved.
-When the total number of defects per wafer is 200 or more and less than 500, it is judged to be good because it can be put into practical use.
-If the total number of defects per wafer is 500 or more, the yield of non-defective semiconductors is extremely deteriorated, so that it cannot be put into practical use and is judged to be defective.

3.5. Evaluation Results Tables 1 and 2 show the compositions of the chemical mechanical polishing compositions of Examples and Comparative Examples and the evaluation results.

The following products or reagents were used for each component in Tables 1 and 2.
<Abrasive grains>
-Titania particles A: Titania particles A prepared above
-Aluminum-containing titania particles B to G: Aluminum-containing titania particles B to G produced above.
-Silica: Made by Fuso Chemical Industry Co., Ltd., trade name "PL-3L" (19.5% aqueous dispersion)
-Alumina: Made by Sumitomo Chemical Co., Ltd., Advanced Alumina Series Product Name "AA-04"
The content of the abrasive grains in the table does not represent the content of the aqueous dispersion, but the content converted into the mass of the abrasive grains.
<Basic compound>
-Monoethanolamine: manufactured by Hayashi Junyaku Kogyo Co., Ltd., trade name "ethanolamine"
-Isopropylamine: Made by Tokyo Chemical Industry Co., Ltd., trade name "Isopropanolamine"
-Benzylamine: Made by Tokyo Chemical Industry Co., Ltd., trade name "Benzylamine"
-Diglycolamine: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "2- (2-Aminoethoxy) ethanol"
-Methylamine: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Methylamine (ca. 40% in water, ca. 12 mol / L)" (40% aqueous solution)
-Ethylenediamine: Made by Tokyo Chemical Industry Co., Ltd., trade name "Ethylenediamine Anhydrous"
-Dodecylaminoethylaminoethylglycine: manufactured by Sanyo Chemical Industries, Ltd., trade name "Levon S" (30% aqueous solution)
-Potassium hydroxide: Made by Kanto Chemical Co., Inc., trade name "KOH (potassium hydroxide aqueous solution) 48%"
・ Ammonia: Mitsubishi Gas Chemical Company, trade name "ultra-pure ammonia water" (29% aqueous solution)
The content of the basic compound in the table does not represent the content of the mass of the aqueous solution, but the content converted to the mass of the basic compound.
<Carboxylic acid>
・ Acetic acid: Made by Kanto Chemical Co., Inc., trade name "acetic acid"
・ Malonic acid: Made by Tateyama Kasei Co., Ltd., trade name "malonic acid"
-Tartaric acid: Made by Fuso Chemical Industry Co., Ltd., trade name "Purified L-tartaric acid"
-Maleic acid: Made by Fuso Chemical Industry Co., Ltd., trade name "hydrogenic anhydride"
-Trifluoroacetic acid: manufactured by Tokyo Chemical Industry Co., Ltd., trade name "Trifluoroacetic Acid [Sequation Reagent]"
-Polyacrylic acid: manufactured by Toagosei Co., Ltd., trade name "Julimer AC-10L", weight average molecular weight (Mw) = 50,000
-Citric acid: Made by Fuso Chemical Industry Co., Ltd., trade name "Purified citric acid (crystal) L"
<Oxidizing agent>
-Hydrogen peroxide: Made by Fujifilm Wako Pure Chemical Industries, Ltd., trade name "Hydrogen peroxide" (30% aqueous solution)
The content of hydrogen peroxide in the table does not represent the content of the mass of the aqueous solution, but the content converted to the mass of hydrogen peroxide.
<Other additives>
-Dodecylbenzenesulfonic acid: manufactured by Tokyo Kasei Kogyo Co., Ltd., trade name "Alkylbenesulphonic Acid (soft type) (mixture)"(> 95% aqueous solution), organic acid / polyethylene glycol: manufactured by Toho Chemical Industry Co., Ltd., trade name "PEG-20000" -40W ", average molecular weight of polymerization (Mw) = 20,000 (40% aqueous solution), water-soluble polymer, p-toluenesulfonic acid: manufactured by Gangnam Kako Co., Ltd., trade name" PTS (paratoluenesulfonic acid) ", organic acid -Nitrate: manufactured by Kanto Chemical Co., Ltd., trade name "Nite 1.38" (60-61% aqueous solution), inorganic acid / sulfuric acid: manufactured by Kanto Chemical Co., Ltd., trade name "high-purity sulfuric acid (96%)" (96% aqueous solution) , Inorganic acid The content of other components in the table does not represent the content of the mass of the aqueous solution, but the content converted to the mass of the other components.

In Examples 1 to 12, the composition for chemical mechanical polishing according to the present invention, which contains (A) aluminum-containing titania particles and (B) a basic compound and has a pH of 7 or more and 13 or less, is used. As a result, it was found that the ruthenium film can be polished at high speed and the polishing scratches on the surface to be polished with silicon oxide can be reduced.

Comparative Example 1 is an example in which titanium particles containing no aluminum are used and (B) a composition for chemical mechanical polishing containing no basic compound is used. In such a comparative example, the ruthenium film could not be polished at high speed, and in the defect evaluation, a large number of defects were found on the surface of the silicon oxide polished surface.

Comparative Examples 2 and 3 are examples in which abrasive grains other than the component (A) are used and (B) a composition for chemical mechanical polishing containing a basic compound is used. When silica or alumina was used as the abrasive grains, the ruthenium film could not be polished at high speed. In addition, when a composition for chemical mechanical polishing using alumina was used as the abrasive grains, a large number of defects were found on the surface of the silicon oxide polished surface in the defect evaluation.

Comparative Examples 4 to 5 are examples in which (A) aluminum-containing titania particles are used and (B) a composition for chemical mechanical polishing that does not contain a basic compound is used. In such a comparative example, high-speed polishing of the ruthenium film and defect suppression on the surface to be polished with silicon oxide could not be achieved in a well-balanced manner.

Comparative Example 6 is an example in which the pH was adjusted to 6.0 in the composition of Example 1. In such a comparative example, the ruthenium film could not be polished at high speed because the aluminum-containing titania particles aggregated and the particles became enlarged.

From the above results, it can be seen that the composition for chemical mechanical polishing according to the present invention can polish a semiconductor substrate having a ruthenium-containing portion at high speed and reduce polishing scratches on the surface to be polished.

The present invention is not limited to the above-described embodiment, and various modifications are possible. For example, the present invention includes a configuration substantially the same as the configuration described in the embodiment (for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect). The present invention also includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. The present invention also includes a configuration that exhibits the same effects as the configuration described in the embodiment or a configuration that can achieve the same object. The present invention also includes a configuration in which a known technique is added to the configuration described in the embodiment.

1 ... Aluminum-containing titania particles, 10 ... Base, 12 ... Silicon oxide film, 14 ... Wiring groove, 16 ... Luthenium film, 18 ... Copper film, 42 ... Slurry supply nozzle, 44 ... Slurry (composition for chemical mechanical polishing) Things), 46 ... polishing cloth, 48 ... turntable, 50 ... semiconductor substrate, 52 ... carrier head, 54 ... water supply nozzle, 56 ... dresser, 100 ... object to be treated, 200 ... polishing device

Claims (8)

(A) Titania particles containing aluminum and
(B) Basic compounds and
A composition for chemical mechanical polishing, which contains 7 or more and has a pH of 7 or more and 13 or less. Wherein _{(A) M} A [wt%] of the content of the component, the content of the component (B) is taken as _{M B [wt%],} the value of M A / _{M B} is 0.1 to 10 The composition for chemical mechanical polishing according to claim 1. The composition for chemical mechanical polishing according to claim 1 or 2, wherein the content of the component (A) is 0.1% by mass or more and 10% by mass or less with respect to the total mass of the composition for chemical mechanical polishing. Stuff. The composition for chemical mechanical polishing according to any one of claims 1 to 3, further comprising (C) a carboxylic acid. The composition for chemical mechanical polishing according to any one of claims 1 to 4, further comprising (D) an oxidizing agent. A method for producing a composition for chemical mechanical polishing, which comprises a step of adding (A) aluminum-containing titania particles and (B) a basic compound to a liquid medium. A polishing method comprising a step of polishing a semiconductor substrate using the chemical mechanical polishing composition according to any one of claims 1 to 5. The polishing method according to claim 7, wherein the semiconductor substrate includes a portion containing ruthenium.

Images