TW202106849A - Abrasive grains and chemical mechanical polishing composition - Google Patents

Abstract

The present invention provides a chemical mechanical polishing composition which can inhibit the generation of ruthenium tetroxide with strong toxicity to human body, has excellent stability, and can polish semiconductor substrates (especially substrates containing ruthenium film and silicon oxide film) at high speed, and abrasive grains used for the composition. The abrasive grains of the present invention are used to polish the substrate containing ruthenium, and are prepared by modifying titanium oxide particles with alumina and silica. In the abrasive grains, if the number of moles of titanium oxide is set as MTi, the number of moles of alumina is set as MAl, and the number of moles of silica is set as MSi, then the value of MAl/MTi is 0.004 or more and 2.35 or less, and the value of MSi/MTi is 0.007 or more and 8.00 or less.

Description

Abrasive particles and chemical mechanical polishing composition

The present invention relates to an abrasive grain and a chemical mechanical polishing composition using the abrasive grain.

With the improvement of the manufacturing technology of semiconductor integrated circuits, high integration and high-speed operation of semiconductor elements are required. Along with this, the flatness of the semiconductor substrate surface required in the manufacturing process of the microcircuit in the semiconductor element has become stricter, and chemical mechanical polishing (CMP) has become an indispensable technology in the manufacturing process of the semiconductor element. .

CMP is a kind of polishing composition containing abrasive grains or reagents is supplied to the polishing pad, and the semiconductor substrate is pressed to the polishing pad attached to the platen, so that the semiconductor substrate and the polishing pad are slid to each other to perform chemical treatment on the semiconductor substrate. And mechanical grinding technology. In CMP, chemical reactions based on reagents and mechanical polishing based on abrasives are used to cut the unevenness on the surface of the semiconductor substrate to flatten the surface.

In the miniaturized semiconductor market, at present, semiconductor substrates with tip nodes with a circuit line width of 10 nm have become the mainstream. In addition, in order to realize fine wiring with a circuit line width of 10 nm or less, a technique for improving the embedding of the copper film by applying a ruthenium film with low resistance to the base of the copper film and having good compatibility with copper has been studied.

Under such a background, a ruthenium film polishing composition (slurry) has been studied for planarizing a ruthenium film as a next-generation semiconductor material by CMP (for example, refer to Patent Literature 1 to Patent Literature 2). As such a ruthenium film polishing composition, in order to increase the polishing rate of the ruthenium film, a slurry in which abrasive grains such as aluminum oxide or titanium oxide and an oxidizing agent are used together has been studied. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2009-514219 [Patent Document 2] Japanese Patent Publication No. 2010-535424

[The problem to be solved by the invention] However, in CMP, in order to increase the polishing rate of the ruthenium film, it is necessary to use a ruthenium film polishing composition containing an oxidizing agent with high oxidizing power and/or abrasive grains with high hardness. However, in CMP using a ruthenium film polishing composition containing an oxidant with high oxidizing power, ruthenium tetroxide, which is highly toxic to the human body, is likely to be produced, which may hinder the production process.

Furthermore, as a material constituting the semiconductor substrate, in addition to a copper film or a ruthenium film, there are also insulating films such as a silicon oxide film. In the prior art, it is difficult to polish the surface of such a semiconductor substrate in which multiple materials are mixed at high speed. If it can be realized, it can be expected to bring about high throughput.

Therefore, several aspects of the present invention provide a method for suppressing the production of ruthenium tetroxide, which is highly toxic to the human body, and has excellent stability, and can perform high-speed polishing on semiconductor substrates (especially substrates containing ruthenium film and silicon oxide film). Composition for chemical mechanical polishing, and abrasive grains used for it. [Means to solve the problem]

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

One aspect of the abrasive grains of the present invention is used for polishing a substrate containing ruthenium, and is formed by modifying titanium oxide particles with aluminum oxide and silicon oxide. The number of moles of titanium oxide in the abrasive grains is M _Ti , When the molar number of alumina is M _Al and the molar number of silicon _{oxide is M Si} , _{the value of M Al} /M _Ti is 0.004 or more and 2.35 or less, and _{the value of M Si} /M _Ti is 0.007 or more and 8.00 the following.

In one aspect of the abrasive particles, it may be: At least one selected from the group consisting of fatty acids and their salts is adsorbed or coated on at least a part of the outer layer of the abrasive particles.

One aspect of the abrasive grains of the present invention is used to polish a substrate containing ruthenium, and is formed by modifying titanium oxide particles with aluminum oxide and silicon oxide. At least one selected from the group consisting of fatty acids and their salts is adsorbed or coated on at least a part of the outer layer of the abrasive particles.

In any aspect of the abrasive particles, it may be: The fatty acids and their salts are selected from caprylic acid, capric acid, lauric acid, myristic acid, isomyristic acid, palmitic acid, isopalmitic acid, stearic acid, isostearic acid, arachidic acid, undecylenic acid, At least one of the group consisting of oleic acid, myristic acid, elaidic acid, linoleic acid, hypolinoleic acid, arachidic acid and their salts.

One aspect of the chemical mechanical polishing composition of the present invention contains abrasive grains in any of the above-mentioned aspects.

An aspect of the chemical mechanical polishing composition of the present invention is used for polishing a substrate containing ruthenium, and Contains (A) abrasive grains made by modifying titanium oxide particles with aluminum oxide and silicon oxide.

In any aspect of the composition for chemical mechanical polishing, it may further contain (B) a polyether compound.

In any aspect of the composition for chemical mechanical polishing, the pH may be 7 or more and 13 or less.

In any aspect of the composition for chemical mechanical polishing, it may further contain (C) an oxidizing agent. [Effects of the invention]

According to the chemical mechanical polishing composition containing the abrasive grains of the present invention, the production of ruthenium tetroxide, which is highly toxic to the human body, is suppressed, and the stability is also excellent. It can be used for semiconductor substrates, especially substrates containing ruthenium films and silicon oxide films. High speed grinding. In this way, high production quantification in the manufacture of next-generation semiconductor devices can be achieved.

Hereinafter, preferred embodiments of the present invention will be described in detail. In addition, the present invention is not limited to the following embodiments, and includes various modifications implemented within a scope that does not change the gist of the present invention.

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

1. Abrasive particles The abrasive grains according to one embodiment of the present invention are abrasive grains obtained by modifying titanium oxide particles with aluminum oxide and silicon oxide for polishing a substrate containing ruthenium. Hereinafter, the abrasive grains of this embodiment will be described in detail.

In the abrasive grains of this embodiment, the titanium oxide particles are modified with aluminum oxide and silicon oxide. In the present invention, "modified by aluminum oxide and silicon oxide" means that aluminum oxide and silicon oxide coat at least a part of the surface of titanium oxide particles. In addition, in the present invention, it is assumed that aluminum hydroxide (Al(OH) ₃ ) is contained in "alumina".

In general, since the surface of titanium oxide particles is chemically active, it has a side that easily reacts with other composition components such as (C) an oxidizing agent described later. On the other hand, in the abrasive grains of the present embodiment, since the titanium oxide particles are modified by alumina and silica, it is easy to control this activity, has moderate hardness, and can reduce the resistance to (C) oxidizing agent and other components. Reactivity of ingredients. Therefore, the chemical mechanical polishing composition containing the abrasive grains of the present embodiment is less likely to cause blistering, etc., and also less likely to cause the disappearance of the oxidizing agent and the like in the composition. As a result, the substrate containing the ruthenium film and the silicon oxide film can be polished stably at high speed.

The abrasive grain of this embodiment has a coating of aluminum oxide and silicon oxide. The coating may have a coating layer of aluminum oxide on the inside and a coating layer of silicon oxide on the outside, or it may have a coating on the inside. The coating layer of silicon oxide has a configuration of a coating layer of aluminum oxide on the outside. Moreover, it may be a mixed coating layer of aluminum oxide and silicon oxide.

In addition, as will be described later, the abrasive grains of this embodiment are present on at least a part of the coating layer (also referred to as the "outer layer" in this specification) modified with alumina and silica to adsorb or coat fatty acids and/ Or in the case of fatty acid salts. In this case, a coating layer with silica on the inside and a coating layer with alumina on the outside can be used to make the fatty acid and/or fatty acid salt more firmly adsorb or coat the particles, so it is preferable .

The titanium oxide that is the main component of the abrasive grains of the present embodiment may be any of rutile, anatase, amorphous, and mixtures thereof, but is preferably rutile.

The particle shape of the abrasive grains of the present embodiment is not particularly limited, and may be needle-shaped, rod-shaped, plate-shaped, spherical, or the like. Examples of the plate shape include a hexagonal plate shape, and examples of the rod shape include a hexagonal column shape. Among them, from the viewpoint of suppressing the occurrence of scratches on the polished surface, the spherical shape is preferred. In addition, the shape of the particles can be observed with a scanning electron microscope.

Let the number of moles _{of titanium oxide (TiO 2} ) in the abrasive grains of the present embodiment _{be M Ti} and the number of moles of aluminum oxide (Al ₂ O ₃ ) be M _Al and the moles of silicon oxide (SiO ₂ ) When the number is M _Si , _{the value of M Al} /M _Ti is 0.004 or more and 2.35 or less, and _{the value of M Si} /M _Ti is preferably 0.007 or more and 8.00 or less. The lower limit of M _Al /M _Ti is preferably 0.004, more preferably 0.01, and particularly preferably 0.03. The upper limit of M _Al /M _Ti is preferably 2.35, more preferably 1.00, and particularly preferably 0.10. Furthermore, _{the lower limit of M Si} /M _Ti is preferably 0.007, more preferably 0.01, and particularly preferably 0.05. The upper limit of M _Si /M _Ti is preferably 8.00, more preferably 2.00, and particularly preferably 0.40. _{In addition, the value of M Al/} M _{Ti and} the value of M _Si /M _Ti in the abrasive grains of the present embodiment can be obtained from the measurement results of fluorescent X-ray analysis. Specifically, using abrasive powder as a sample, using a fluorescent X-ray analyzer ZSX Primus IV manufactured by Rigaku Co., Ltd., the voltage of the X-ray tube is 50 kV and the current of the X-ray tube is The measurement is performed under the condition of 50 mA, and the measurement results are obtained in mass% converted from various metal oxides. Next, the value of mass% converted to titanium oxide (TiO _{2 ) in the measurement result is divided by the molecular weight of titanium oxide (TiO 2} ) to calculate M _Ti . Similarly, the value of the mass% converted _{to alumina (Al 2} O ₃ ) in the measurement result is _{divided by the molecular weight of alumina (Al 2} O ₃ ) to calculate M _Al , and the silica (SiO ₂₎ ) The converted mass% value is divided by _{the molecular weight of silicon oxide (SiO 2} ) to calculate M _Si . The values of M _Al /M _Ti and M _Si /M _Ti can be obtained _{by dividing M Al} or M _{Si by M Ti} , respectively.

If the value of M _Al /M _Ti is in the above-mentioned range, and the value of M _Si /M _Ti is the abrasive grain in the above-mentioned range, it is easy to control the activity of the titanium oxide particles. Reactivity of other components such as oxidants. Therefore, in the chemical mechanical polishing composition, the occurrence of blistering or the disappearance of an oxidizing agent and the like are less likely to occur. As a result, the substrate containing the ruthenium film and the silicon oxide film can be polished stably at high speed.

Furthermore, it is preferable that the abrasive grains of this embodiment adsorb or coat fatty acids and/or fatty acid salts on at least a part of the outer layer. If it is abrasive grains in which fatty acids and/or fatty acid salts are adsorbed or coated on at least a part of the outer layer, it is easier to control the activity of titanium oxide particles. Therefore, it has moderate hardness and can reduce the composition of other components such as oxidants. The reactivity. Therefore, in the chemical mechanical polishing composition, the occurrence of blistering or the disappearance of an oxidizing agent and the like are less likely to occur. As a result, the substrate containing the ruthenium film and the silicon oxide film can be polished stably at high speed.

Such fatty acids and their salts are not particularly limited, and examples include caprylic acid, capric acid, lauric acid, myristic acid, isomyristic acid, palmitic acid, isopalmitic acid, stearic acid, isostearic acid, arachidic acid, Undecylenic acid, oleic acid, myristic acid, elaidic acid, linoleic acid, hypolinoleic acid, arachidic acid and their salts. Among them, in consideration of the ease of adsorption or coating on the outer layer of abrasive grains, and the dispersion stability in the composition, palmitic acid, isopalmitic acid, stearic acid, isostearic acid, arachidic acid, and decanoic acid are preferred. Fatty acids with a carbon number of 16 or more, such as monoenoic acid, oleic acid, myristic acid, elaidic acid, linoleic acid, hypolinoleic acid, and arachidic acid, and their salts, more preferably selected from stearic acid, oil At least one of acid and these salts. One type of these fatty acids and these salts may be used, or two or more types may be laminated or mixed for use.

The coating amount of the fatty acid and/or fatty acid salt in the abrasive grains of the present embodiment is preferably in the range of 0.1% by mass to 30% by mass, and more preferably in the range of 0.5% by mass to 20% by mass relative to the titanium oxide particles. More preferably, it is in the range of 1% by mass to 15% by mass.

The absolute value of the zeta potential of the abrasive grains of the present embodiment is preferably 25 mV or more, more preferably 30 mV or more, and particularly preferably 35 mV in a chemical mechanical polishing composition having a pH of 7 or more and 13 or less the above. In the chemical mechanical polishing composition in the pH range, if the absolute value of the zeta potential of the abrasive grains of the present embodiment is within the above range, the dispersibility of the abrasive grains is improved. In addition to the case of a film and a silicon oxide film substrate, there are cases where scratches and the like are not easily generated.

It is preferable that the average particle diameter of the abrasive grain of this embodiment is 10 nm or more and 300 nm or less. The lower limit of the average particle diameter of the abrasive grains of this embodiment is preferably 10 nm, more preferably 20 nm, and particularly preferably 25 nm. The upper limit of the average particle diameter of the abrasive grains in this embodiment is preferably 300 nm, more preferably 200 nm, and particularly preferably 150 nm. By having an average particle diameter in the above-mentioned range, a sufficient polishing rate can be obtained with respect to a substrate containing a ruthenium film and a silicon oxide film, and a chemical mechanical polishing composition with excellent stability that is unlikely to cause particle sedimentation/separation can be obtained , So good performance can be achieved. In addition, the average particle diameter of the abrasive grains can be determined as follows: For a sample obtained by drying a part of the abrasive grain dispersion, for example, an automatic image processing and analysis device (Nireco manufactured Luzekus AP ( LuzexAP)) Perform image processing, measure the primary particle size of 2000 particles, and calculate from the measured value.

The manufacturing method of the abrasive grain of this embodiment as mentioned above is not specifically limited, For example, it can manufacture by the following general method.

The abrasive grains of the present embodiment can be obtained by subjecting untreated titanium oxide particles to surface treatment or the like with aluminum oxide and silicon oxide. Here, untreated titanium oxide particles can be obtained using various known methods. As such a method, for example, a method of neutralizing and hydrolyzing the titanium tetrachloride aqueous solution with an alkali and sintering the obtained hydrous titanium dioxide; or the method of neutralizing and hydrolyzing the titanium tetrachloride aqueous solution with an alkali to obtain The hydrous titanium dioxide is heated with sodium hydroxide, and the obtained reaction product is heated and matured with an acid.

Regarding the surface modification when the untreated titanium oxide particles are surface-modified with aluminum oxide and silicon oxide, various well-known methods can also be used. As such a method, for example, a method of dispersing the untreated titanium oxide particles in a solvent such as water to form a slurry, and adding an aluminum source or a silicon source to the slurry can be used. As the aluminum source, sodium aluminate, aluminum sulfate, or the like can be used. Furthermore, as the silicon source, sodium silicate or the like can be used. The addition amount of the aluminum source and the silicon source can be adjusted appropriately according to the desired modification amount within a range that _{satisfies the prescribed ranges of M Al} /M _Ti and M _Si /M _Ti.

Then, by adjusting the pH of the slurry to neutralize the aluminum source or silicon source, the oxide and/or hydroxide derived from the aluminum source or silicon source can be precipitated (modified) in the untreated The surface of titanium oxide particles. The pH of the slurry can be appropriately set according to the type of aluminum source or silicon source used. In addition, regarding the surface modification, the surface modification of silica may be performed after the surface modification of alumina, or the surface modification of alumina may be performed after the surface modification of silica. Furthermore, the surface modification of aluminum oxide and silicon oxide can also be performed at the same time.

Furthermore, if necessary, various fatty acids and/or fatty acid salts can be adsorbed or coated on the titanium oxide particles modified with alumina and silica. This adsorption or coating can also be performed using various well-known methods. As such a method, for example, a method of adding a fatty acid and/or a fatty acid salt to an aqueous slurry containing the titanium oxide particles modified with aluminum oxide and silicon oxide. As fatty acids and fatty acid salts, various fatty acids exemplified above, sodium salts of these, and the like can be used. The addition amount of fatty acid and/or fatty acid salt can be appropriately adjusted according to the desired adsorption or coating amount. The pH of the slurry is adjusted to neutralize and precipitate the fatty acid derived from the fatty acid and/or the fatty acid salt, and is adsorbed or coated on the outer layer of the titanium oxide particles modified with alumina and silica. The pH of the slurry can be appropriately set according to the fatty acid and/or fatty acid salt used.

The titanium oxide particles after the surface treatment can also be cleaned by various known methods. By drying the solid content after washing by various well-known methods, the powder of the abrasive grain of this embodiment can be obtained. Regarding the powder of the abrasive grains obtained in this way, the particle size can also be adjusted by pulverizing by various known methods.

2. Composition for chemical mechanical polishing The chemical mechanical polishing composition of one embodiment of the present invention is used for polishing a substrate containing ruthenium, and contains (A) abrasive grains obtained by modifying titanium oxide particles with aluminum oxide and silicon oxide (hereinafter also referred to simply as "(A)) Abrasive"). Hereinafter, each component contained in the chemical mechanical polishing composition of the present embodiment will be described in detail.

2.1. (A) Abrasive particles The chemical mechanical polishing composition of the present embodiment contains (A) abrasive grains in which titanium oxide particles are modified with aluminum oxide and silicon oxide. (A) In this embodiment, the abrasive grains obtained by modifying the titanium oxide particles with aluminum oxide and silicon oxide are the abrasive grains described in the section of "1. Abrasive grains" above.

In general, since the surface of titanium oxide particles is chemically active, it has a side that easily reacts with water, oxygen, nitrogen, oxidants, and the like. On the other hand, the chemical mechanical polishing aqueous dispersion of this embodiment contains (A) abrasive grains, so it is easy to control the activity of titanium oxide particles, has moderate hardness, and can reduce the reaction with other components such as oxidants. Sex. Therefore, the chemical mechanical polishing composition of the present embodiment is less likely to cause blistering or the like, and it is also less likely to cause the disappearance of the oxidizing agent and the like in the composition. As a result, the substrate containing the ruthenium film and the silicon oxide film can be polished stably at high speed.

In addition, the composition and physical properties of (A) abrasive grains ( _{values of M Al} /M _Ti and M _Si /M _Ti , fatty acids and their salts, etc.) and physical properties are the same as those described in the item "1. Abrasive grains" above. The same, so the description is omitted.

From the viewpoint of polishing a substrate containing a ruthenium film and a silicon oxide film at high speed, the content of (A) abrasive grains is preferably 0.1% by mass or more relative to the total mass of the chemical mechanical polishing composition, and more preferably 0.3% by mass or more, more preferably 0.5% by mass or more. From the viewpoint of reducing the occurrence of polishing damage on the surface to be polished, the content of (A) abrasive grains is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 3% by mass or less.

2.2. (B) Polyether compound The composition for chemical mechanical polishing of this embodiment may contain (B) a polyether compound. (B) The polyether compound has a function of improving the dispersibility of (A) abrasive grains. In particular, when a fatty acid and/or fatty acid salt is adsorbed or coated on at least a part of the outer layer of (A) abrasive grains, the hydrophobic group of the fatty acid and/or fatty acid salt and the hydrophobic group of (B) the polyether compound Due to the interaction, (B) the hydrophilic group of the polyether compound is aligned on the water phase side, so (A) the dispersibility of abrasive grains is improved. Thereby, the substrate containing the ruthenium film and the silicon oxide film can be polished stably at high speed, and the occurrence of polishing damage on the polished surface can be reduced.

The (B) polyether compound is not particularly limited as long as it contains two or more ether bonds. Examples include random or block copolymers of silicon-containing polymers and polymers having a polyether structure, and cyclic Ethylene oxide (EO) and propylene oxide (PO) and other compounds with alkyleneoxy groups. (B) Specific examples of the polyether compound include polyether modified silicone, polyoxyalkylene alkyl ether, polyoxyalkylene aryl ether, polyoxyalkylene sorbitan fatty acid ester For example, since the dispersibility of (A) abrasive grains can be further improved, polyether modified silicone is preferred.

(B) The lower limit of the weight average molecular weight (Mw) of the polyether compound is preferably 100, more preferably 300, and particularly preferably 500. (B) The upper limit of the weight average molecular weight (Mw) of the polyether compound is preferably 100,000, more preferably 70,000, and particularly preferably 50,000. If the weight average molecular weight of the (B) polyether compound is within the above range, the (B) polyether compound is likely to be adsorbed on the outer layer of the (A) abrasive grains, so the dispersibility of the (A) abrasive grains may be further improved. . In addition, the "weight average molecular weight (Mw)" in this specification refers to the weight average molecular weight in terms of polyethylene glycol as measured by gel permeation chromatography (Gel Penetration ChromatograpHy, GPC).

When the (B) polyether compound is contained, the lower limit of the content of the (B) polyether compound is effective in obtaining the effect of improving the dispersibility of the (A) abrasive grains, compared to chemical The total mass of the composition for mechanical polishing is preferably 0.001% by mass, more preferably 0.003% by mass, and particularly preferably 0.01% by mass. From the viewpoint of reasonably maintaining the viscosity of the chemical mechanical polishing composition and simultaneously performing high-speed polishing on a substrate containing a ruthenium film and a silicon oxide film, the upper limit of the content of (B) polyether compound is preferably 15 mass %, more preferably 10% by mass, particularly preferably 3% by mass.

2.3. (C) Oxidizer The composition for chemical mechanical polishing of the present embodiment may contain (C) an oxidizing agent within a range that does not oxidize the ruthenium film to generate ruthenium tetroxide in the CMP step. By containing the (C) oxidant, metals such as ruthenium are oxidized to promote the complex reaction with the components of the polishing liquid, and thereby a fragile modified layer can be formed on the polished surface, which has the effect of facilitating polishing.

(C) The oxidizing agent includes, for example, ammonium persulfate, potassium persulfate, hydrogen peroxide, ferric nitrate, Diammonium Cerium Nitrate, potassium hypochlorite, ozone, potassium periodate, and peracetic acid. Among these oxidants, from the viewpoint of suppressing the generation of ruthenium tetroxide, at least one selected from potassium periodate, potassium hypochlorite, and hydrogen peroxide is preferred, and hydrogen peroxide is more preferred. These (C) oxidants may be used alone or in combination of two or more.

When the (C) oxidant is contained, the lower limit of the content of the (C) oxidant is relative to the chemical mechanical polishing composition from the viewpoint of preventing insufficient oxidation of ruthenium and other metals and lowering the polishing rate The total mass of is preferably 0.001% by mass, more preferably 0.005% by mass, and particularly preferably 0.01% by mass. From the viewpoint of preventing the generation of ruthenium tetroxide due to excessive oxidation of ruthenium, the upper limit of the content of the (C) oxidant is preferably 5 mass%, more preferably 3 mass%, and particularly preferably 1 mass%.

2.4. Other ingredients The chemical mechanical polishing composition of the present embodiment may contain a pH adjuster and the like as necessary in addition to water as the main liquid medium.

＜Water＞ The chemical mechanical polishing composition of this embodiment contains water as a main liquid medium. The water is not particularly limited, but pure water is preferred. Water may be prepared as the remainder of the constituent materials of the chemical mechanical polishing composition, and the content of water is not particularly limited.

＜pH adjuster＞ The lower limit of the pH of the chemical mechanical polishing composition of the present embodiment is preferably 7, more preferably 8, and particularly preferably 9. The upper limit of the pH of the chemical mechanical polishing composition of the present embodiment is preferably 13, more preferably 12.5, and particularly preferably 12. If the pH is 7 or higher, the absolute value of the dynamic potential of (A) abrasive grains in the chemical mechanical polishing composition increases and the dispersibility improves. Therefore, there are substrates that can stably polish a ruthenium-containing film and a silicon oxide film at a high speed. And it can reduce the occurrence of polishing damage on the polished surface. Moreover, if the pH is 13 or less, the operability during production will improve.

In addition, the chemical mechanical polishing composition of the present embodiment may contain a pH adjuster for the purpose of adjusting the pH in the above-mentioned range. Examples of the pH adjuster include hydroxides of alkali metals such as sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide, amines, and ammonia. These pH adjusters may be used individually by 1 type, and may mix and use 2 or more types. Moreover, by adding mineral acids such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, etc.; citric acid, malonic acid, maleic acid, tartaric acid, malic acid, succinic acid, phthalic acid, etc., in addition to the pH adjusting agent. Organic acids, etc., may increase the polishing rate of silicon oxide films.

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

2.5. Purpose The chemical mechanical polishing composition of the present embodiment, as described above, suppresses the generation of ruthenium tetroxide which is highly toxic to the human body in the CMP of a substrate containing a ruthenium film and a silicon oxide film, and has excellent stability. Films and silicon oxide film substrates are polished at high speed. Therefore, the chemical mechanical polishing composition of the present embodiment is suitable as a semiconductor substrate in which a ruthenium film as a next-generation semiconductor material is applied to a base of a copper film. Abrasive materials for mechanical grinding. In addition, the semiconductor substrate may have a barrier metal film between the ruthenium film and the copper film, or may have a silicon nitride film as a mask film, a passivation film, or a barrier film.

2.6. Preparation method of chemical mechanical polishing composition The chemical mechanical polishing composition of the present embodiment can be prepared by dissolving or dispersing the respective components in a liquid medium such as water. The method of dissolution or dispersion is not particularly limited, and any method can be applied as long as the dissolution or dispersion can be performed uniformly. Moreover, there are no particular restrictions on the mixing order or mixing method of the respective components.

Furthermore, the chemical mechanical polishing composition of the present embodiment can also be prepared as a concentrated stock solution, and used after being diluted with a liquid medium such as water during use.

3. Grinding method The polishing method of one embodiment of the present invention includes a step of polishing a semiconductor substrate containing a ruthenium film and a silicon oxide film using the chemical mechanical polishing composition. The composition for chemical mechanical polishing can suppress the generation of ruthenium tetroxide which is highly toxic to human body when chemical mechanical polishing is performed on a ruthenium film, has excellent stability, and can perform high-speed polishing on a substrate containing a ruthenium film and a silicon oxide film. Therefore, the polishing method of this embodiment is suitable as a polishing method for chemical mechanical polishing of a substrate containing a ruthenium film and a silicon oxide film in a semiconductor substrate obtained by applying a ruthenium film as a next-generation semiconductor material to a base of a copper film. material. Hereinafter, a specific example of the polishing method of this embodiment will be described in detail using drawings.

3.1. The processed body FIG. 1 is a cross-sectional view schematically showing a to-be-processed object suitable for using the polishing method of this embodiment. The processed body 100 is formed through the following steps (1) to (4).

(1) First, as shown in Fig. 1, a base 10 is prepared. The base 10 may include, for example, a silicon substrate and a silicon oxide film formed thereon. Furthermore, functional devices such as a transistor (not shown) may be formed on the base 10. Next, a silicon oxide film 12, which is an insulating film, is formed on the substrate 10 using 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 on 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 can be formed by, for example, chemical vapor deposition (CVD) or atomic layer deposition (ALD) using a ruthenium precursor, or physical vapor deposition (Physical Vapor Deposition) such as sputtering. , PVD) to form.

(4) Next, a copper film 18 of 10,000 Å to 15,000 Å is deposited by chemical vapor deposition or electroplating. 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 gold containing copper is preferably 95% by mass or more.

3.2. Grinding method 3.2.1. The first grinding step FIG. 2 is a cross-sectional view schematically showing the object to be processed 100 at the end of the first polishing step. As shown in FIG. 2, the first polishing step is a step of polishing the copper film 18 using the chemical mechanical polishing composition for the copper film until the ruthenium film 16 is exposed.

3.2.2. The second grinding step FIG. 3 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. 3, 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 chemical mechanical polishing composition. In the second polishing step, the chemical mechanical polishing composition is used, so the generation of ruthenium tetroxide, which is highly toxic to the human body, is suppressed, and the ruthenium film and the silicon oxide film can be polished at high speed. By passing through the second polishing step, a next-generation semiconductor device with excellent flatness of the polished surface can be manufactured.

3.3. Chemical mechanical polishing device In the first polishing step and the second polishing step, for example, a polishing device 200 as shown in FIG. 4 can be used. FIG. 4 is a perspective view schematically showing the polishing device 200. In the first polishing step and the second polishing step, the slurry (chemical mechanical polishing composition) 44 is supplied from the slurry supply nozzle 42, and the turntable 48 to which the polishing cloth 46 is attached is rotated while holding The carrier head 52 of the semiconductor substrate 50 is brought into contact with each other. In addition, FIG. 4 also shows the water supply nozzle 54 and the dresser 56 together.

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

Examples of commercially available polishing devices include models "EPO-112" and "EPO-222" manufactured by Ebara Manufacturing Co., Ltd.; models "LGP-510" and "LGP-552 manufactured by Lapmaster SFT Co., Ltd." "; Models "Mirra" and "Reflexion" manufactured by Applied Material; Models "POLI-400L" manufactured by G&P Technology; Models "POLI-400L" manufactured by AMAT "Reflexion LK" and so on.

4. Example Hereinafter, the present invention will be described through examples, but the present invention is not limited by these examples in any way. In addition, "parts" and "%" in this example are quality standards unless otherwise specified.

4.1. Preparation of Aqueous Dispersion <Preparation of Aqueous Dispersion A1> _{Keep the titanium tetrachloride aqueous solution (200 g/L in terms of TiO 2} ) at room temperature, and at the same time, neutralize with sodium hydroxide aqueous solution to make the colloid Amorphous amorphous titanium hydroxide precipitates, and then matures to obtain a rutile-type titanium dioxide sol. The sol was filtered and washed, and the obtained washed cake was sintered at 600° C. for 3 hours, and wet pulverized with a sand mill to prepare a slurry of titanium oxide particles. After heating the slurry to 80°C and maintaining the temperature, while fully stirring, add _{10% by mass of sodium silicate in terms of SiO 2} to the titanium oxide, and use 20% by mass of sulfuric acid to make the pH of the slurry 8.5～ 9.5, thereby coating the titanium oxide particles with silicon dioxide. _{Then, 4% by mass of sodium aluminate in terms of Al 2} O ₃ relative to the titanium oxide was added, and 20% by mass sulfuric acid was used to make the pH of the slurry 7.5 to 8.5, thereby utilizing aluminum hydrated oxide (aluminum oxide). ) Coated with titanium oxide particles. Furthermore, 20% by mass sulfuric acid was used to make the pH of the slurry about 5, sodium stearate was added at 5% by mass in terms of stearic acid relative to the titanium oxide, and after stirring and mixing for about 1 hour, the temperature of the slurry was changed After cooling to 50°C or lower, the titanium oxide particles were coated with stearic acid. After filtering, washing, and drying, it was pulverized with a hammer mill to obtain abrasive grains A. The average primary particle size of the abrasive grain A was 40 nm. In addition, in abrasive grain A, the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) is 0.04, and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) is 0.15.

Next, 60.2 parts by mass of pure water is mixed with 4.5 parts by mass of PEG-11 methyl ether dimethyl silicone (trade name "KF-6011", manufactured by Shin-Etsu Silicone Co., Ltd.), which is a Si-based polyether compound as a polyether compound. . While stirring the mixed liquid, 30 parts by mass of the abrasive grain A was put into it, and mixed thoroughly with a disperser. To this, 0.3 parts by mass of monoethanolamine and 5.0 parts by mass of sorbitan fatty acid ester (trade name "SORGEN 30", manufactured by Daiichi Industrial Chemical Co., Ltd.) were added, and they were thoroughly mixed with a disperser. This was wet pulverized with a sand mill to obtain an aqueous dispersion A1.

<Preparation of Aqueous Dispersion A2> Based on the production method of the abrasive grain A, the addition amount of sodium silicate was increased to 16.6% by mass _{in terms of SiO 2 relative to titanium oxide.} Except for this, abrasive grains B were obtained in the same manner as in the method for producing abrasive grains A. The average primary particle size of the abrasive grain B was 40 nm, the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) was 0.04, and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) was 0.23. This abrasive grain B was dispersed in pure water in the same manner as in the preparation method of the aqueous dispersion A1 to obtain an aqueous dispersion A2.

<Preparation of Aqueous Dispersion A3> Based on the production method of the abrasive grain A, the amount of sodium silicate added was reduced to 4.1% by mass _{in terms of SiO 2 relative to titanium oxide.} Except for this, abrasive grains C were obtained in the same manner as the method for producing abrasive grains A. The average primary particle size of the abrasive grain C is 40 nm, the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) is 0.04, and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) is 0.06. This abrasive grain C was dispersed in pure water in the same manner as in the preparation method of the aqueous dispersion A1 to obtain an aqueous dispersion A3.

<Preparation of Aqueous Dispersion A4> Based on the production method of the abrasive grain A, the addition amount of sodium silicate was increased to _{15% by mass in terms of SiO 2} with respect to titanium oxide, and the sodium aluminate The addition amount was increased to 6% by mass _{in terms of Al 2} O _{3 relative to titanium oxide.} Except for this, abrasive grains D were obtained in the same manner as in the method for producing abrasive grains A. The average primary particle size of the abrasive grain D was 40 nm, the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) was 0.05, and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) was 0.21. This abrasive grain D was dispersed in pure water in the same manner as in the preparation method of the aqueous dispersion A1 to obtain an aqueous dispersion A4.

<Preparation of Aqueous Dispersion A5> Based on the production method of the abrasive grain A, sodium laurate was used instead of sodium stearate. Except for this, abrasive grains E were obtained in the same manner as in the method of producing abrasive grains A. The average primary particle size of the abrasive grain E was 40 nm, the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) was 0.04, and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) was 0.15. This abrasive grain E was dispersed in pure water in the same manner as in the preparation method of the aqueous dispersion A1 to obtain an aqueous dispersion A5.

<Preparation of Aqueous Dispersion A6> Based on the production method of the abrasive grain A, sodium oleate was used instead of sodium stearate. Except for this, the abrasive grains F were obtained in the same manner as in the method of manufacturing the abrasive grains A. The average primary particle size of the abrasive particles F is 40 nm, the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) is 0.04, and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) is 0.15. This abrasive grain F was dispersed in pure water in the same manner as in the preparation method of the aqueous dispersion A1 to obtain an aqueous dispersion A6.

<Preparation of Aqueous Dispersion A7> In the preparation method of the aqueous dispersion A1, the added polyether compound was changed to polyoxyethylene sorbitan monooleate (trade name "Tween 80" as a non-Si-based polyether compound). , Manufactured by Tokyo Chemical Industry Co.). Except for this, the water-based dispersion A7 was obtained in the same manner as in the preparation method of the above-mentioned water-based dispersion A1.

<Preparation of aqueous dispersion A8> In the preparation method of the water-based dispersion A1, the added polyether compound was changed to polyoxyalkylene decyl ether as a non-Si-based polyether compound (trade name "Noigen (Noigen) XL-140" , Manufactured by the First Industrial Chemical Company). Except for this, an aqueous dispersion A8 was obtained in the same manner as the production method of the above-mentioned aqueous dispersion A1.

<Preparation of aqueous dispersion A9> In the preparation method of the water-based dispersion A1, the added polyether compound was changed to polyoxyethylene tridecyl ether as a non-Si-based polyether compound (trade name "Noigen (Noigen) TDS-120" , Manufactured by the First Industrial Chemical Company). Except for this, the water-based dispersion A9 was obtained in the same manner as in the preparation method of the above-mentioned water-based dispersion A1.

＜Preparation of aqueous dispersion A10＞ In the preparation method of the water-based dispersion A1, the added polyether compound was changed to a non-Si-based polyether compound, a polyoxyethylene styrenated phenyl ether (trade name "Noigen (Noigen) EA-177 ", manufactured by Daiichi Industrial Chemical Company). Except for this, the aqueous dispersion A10 was obtained in the same manner as the preparation method of the aqueous dispersion A1.

<Preparation of Aqueous Dispersion A11> Based on the production method of the abrasive grain A, in the production of untreated titanium oxide particles, the sintering temperature of the cleaning cake of the titanium dioxide sol was changed to 400°C to obtain the primary particle size Relatively small titanium oxide particles. In the subsequent surface treatment, the addition amount of sodium silicate was changed _{to 20% by mass in terms of SiO 2} relative to titanium oxide, and the addition amount of sodium aluminate was changed to Al ₂ O _{3 relative to titanium oxide.} The conversion amount was 8% by mass, and the addition amount of sodium stearate was changed to 10% by mass in terms of stearic acid relative to titanium oxide. This is to reduce the primary particle size of the titanium oxide particles and to make the thickness of the coating layer approximately the same as the abrasive grains A to F. Except for this, abrasive grains G were obtained in the same manner as in the preparation method of the water-based dispersion 1. The average primary particle size of the abrasive grain G was 20 nm, the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) was 0.07, and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) was 0.28. In 58.9 parts by mass of pure water, PEG-11 methyl ether dimethyl silicone (trade name "KF-6011", manufactured by Shin-Etsu Silicone Co., Ltd.) as a polyether compound, 7.5 parts by mass, abrasive G 25.0 parts by mass, 0.6 parts by mass of ethanolamine and 8.0 parts by mass of sorbitan fatty acid ester (trade name "SORGEN 30", manufactured by Daiichi Industrial Chemical Co., Ltd.) are combined with the production method of the aqueous dispersion A1 Aqueous dispersion A11 was obtained in the same process.

<Comparative Example Preparation of Water-based Dispersion B1> Based on the production method of the abrasive grain A, the amount of sodium silicate added _{was 24% by mass in terms of SiO 2} relative to titanium oxide, and the use of aluminum was omitted. Sodium surface treatment step. Except for this, the abrasive grains H were obtained in the same manner as in the method of manufacturing the abrasive grains A. The average primary particle size of the abrasive grains H is 40 nm, the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) is 0, and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) is 0.34. In pure water 75.2 parts by mass, PEG-11 methyl ether dimethyl silicone (trade name "KF-6011", manufactured by Shin-Etsu Silicone Co., Ltd.) as a polyether compound, 4.5 parts by mass, abrasive H 15.0 parts by mass, 0.3 parts by mass of ethanolamine and 5.0 parts by mass of sorbitan fatty acid ester (trade name "SORGEN 30", manufactured by Daiichi Industrial Chemical Co., Ltd.) are combined with the production method of the aqueous dispersion A1 The water-based dispersion B1 of the comparative example was obtained by the same procedure.

<Preparation of Comparative Example Water-Based Dispersion B2> Based on the production method of the abrasive grain A, the surface treatment step using sodium silicate and sodium aluminate was omitted. Except for this, abrasive grains I were obtained in the same manner as in the method for producing abrasive grains A. The average primary particle size of the abrasive particles I was 40 nm, and the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) were all zero. This abrasive grain I was dispersed in pure water in the same manner as in the preparation method of the water-based dispersion A1 to obtain a comparative example water-based dispersion B2.

<Preparation of aqueous dispersion B3 of the comparative example> Based on the production method of the abrasive grain A, the surface treatment step using sodium silicate was omitted, and the addition amount of sodium aluminate was set to be Al _{2 relative to titanium oxide.} O _{3 is} converted into 5 mass%. Except for this, abrasive grains J were obtained in the same manner as the method for producing abrasive grains A. The average primary particle size of the abrasive grain J is 40 nm, the molar ratio of aluminum oxide to titanium oxide (M _Al /M _Ti ) is 0.05, and the molar ratio of silicon oxide to titanium oxide (M _Si /M _Ti ) is 0. In 43.2 parts by mass of pure water, PEG-11 methyl ether dimethyl silicone (trade name "KF-6011", manufactured by Shin-Etsu Silicone Co., Ltd.) as a polyether compound, 6.75 parts by mass, 45.0 parts by mass of abrasive grain J, 0.3 parts by mass of ethanolamine and 5.0 parts by mass of sorbitan fatty acid ester (SORGEN 30: manufactured by Daiichi Industrial Chemical Co., Ltd.) were prepared in the same process as the preparation method of the aqueous dispersion A1 Comparative Example: Water-based dispersion B3.

4.2. Evaluation of physical properties of abrasive grains The average primary particle size and composition analysis of the abrasive grains obtained above were respectively performed by the evaluation methods described below.

＜Average primary particle size＞ A transmission electron microscope (Hitachi, Ltd., model "H-7000") was used to photograph abrasive grains, and an automatic image processing and analysis device (Luzex AP manufactured by Nireco) was used for image processing. The primary particle size was measured for 2000 particles, and the average value was used as the average primary particle size.

<Composition analysis> Measured using a fluorescent X-ray analyzer (manufactured by Rigaku, model "ZSX Primus IV"). The measurement was performed using a sample (abrasive powder) that was put in an aluminum ring and formed by pressing with a hydraulic press. Based on the measurement result, to calculate the number of moles of the titanium oxide _{of Ti} is set to M, the number of moles of aluminum to M _Al, M _Al / M _Ti and M is number of moles of silicon oxide is set to M _{Si Si} / M The value of _Ti.

4.3. Preparation and evaluation of chemical mechanical polishing composition 4.3.1. Preparation of chemical mechanical polishing composition The water-based dispersion is added to a polyethylene container so that the content of abrasive grains in the chemical mechanical polishing composition becomes 1% by mass, and the oxidizing agent content is 1% by mass, and the pH of the chemical mechanical polishing composition The pH adjuster and pure water were added so as to be 11, thereby preparing the chemical mechanical polishing composition of each example and each comparative example shown in Table 2 in which the total amount of all components was 100 parts by mass.

4.3.2. Evaluation method ＜Evaluation of grinding speed＞ Using the chemical mechanical polishing composition obtained above, an 8-inch diameter wafer with a ruthenium film of 50 nm and a 12 inch diameter wafer with a silicon dioxide film of 20,000 nm were used as the object to be polished. The polishing conditions were 30 Second or 60 second chemical mechanical polishing test.

(Polishing conditions) ·Polishing device: Model "POLI-400L" manufactured by G&P Technology Co., Ltd. ·Polishing pad: "Multi-hard polyurethane pad manufactured by Fujibo; H800-typel (3-1S)"775" ·Supply speed of chemical mechanical polishing composition: 100 mL/min ·Pan speed: 100 rpm ·Slapping head speed: 90 rpm ·Splashing pressure of the polishing head: 2 psi ·Polishing speed (nm/min) = (before polishing The thickness of the film-the thickness of the film after polishing)/polishing time. In addition, the thickness of the ruthenium film is measured by a resistivity measuring machine (model "Σ-5" manufactured by NPS) by the DC four-point probe method. It was measured and calculated from the sheet resistance value and the volume resistivity of ruthenium according to the following equation. Thickness of the ruthenium film (Å)=[Volume resistivity of the ruthenium film (Ω･m)÷sheet resistance value (Ω)]×10 ¹⁰ The thickness of the silicon dioxide film is measured by using a non-contact optical film thickness measuring device ( The thickness is calculated by measuring the refractive index, manufactured by Nanometrics Japan, model "NanoSpec6100".

(Evaluation standard for polishing speed of ruthenium film) The evaluation criteria for the polishing rate of the ruthenium film are as follows. Table 2 shows the polishing rate of the ruthenium film and its evaluation results. · When the polishing speed is 300 Å/min or more, the polishing speed is high, so it is easy to ensure a balance between the polishing speed of other material films in the actual semiconductor polishing, and it is practical, and it is judged to be good. Marked as "A". ·When the polishing speed is less than 300 Å/min, the polishing speed is low, so it is difficult to be practical, and it is judged to be defective and marked as "B".

(Evaluation standard for polishing speed of silicon dioxide film) The evaluation criteria for the polishing speed of the silicon dioxide film are as follows. Table 2 shows the polishing rate of the silicon dioxide film and its evaluation results. ·When the polishing speed is 30 Å/min or more, it can be judged that the polishing performance of silicon dioxide is also sufficient. In actual semiconductor polishing, it was judged that it would bring a good result to ensure the flatness of parts containing both ruthenium and silicon dioxide, and it was marked as "A". · When the polishing rate is less than 30 Å/min, since the polishing rate of silicon dioxide is low, only excessive polishing of the ruthenium film is caused in actual semiconductor polishing. Therefore, it is judged to be difficult to use, and is marked as "B".

＜Defect evaluation＞ A wafer with a ruthenium film with a diameter of 12 inches as an object to be polished was polished for 1 minute under the following conditions. (Grinding conditions) · Grinding device: Model "Reflexion LK" manufactured by AMAT ·Polishing pad: "Multi-hard polyurethane pad; H800-typel (3-1S) 775" manufactured by Fujibo Industries Co., Ltd. ·Supply rate of chemical mechanical polishing composition: 300 mL/min ·Pressure plate speed: 100 rpm ·Rotating speed of grinding head: 90 rpm ·Pressing pressure of grinding head: 2 psi

For the above-mentioned polished wafer with ruthenium film, using a defect inspection device (model "Surfscan SP1" manufactured by KLA Tencor), the total number of defects with a size of 90 nm or more Count. The evaluation criteria are as follows. The total number of defects per wafer and their evaluation results are shown in Table 2. (evaluation standard) · If the total number of defects per wafer is less than 500, it is judged as good, and it is recorded as "A" in the table. · When the total number of defects per wafer is 500 or more, it is judged as defective, and is described as "B" in the table.

<Test on the decomposition rate of hydrogen peroxide contained in the chemical mechanical polishing composition> Put 100 mL of the chemical mechanical polishing composition described in Table 2 into a polyethylene container, close the lid and airtightly, and let it stand for 7 days. After 7 days, the chemical mechanical polishing composition was diluted 10-fold with pure water, and 10 g of a 10% sulfuric acid aqueous solution and 10 g of a 10% potassium iodide aqueous solution were added to 20 g of the diluted solution, respectively, to prepare a hydrogen peroxide decomposition rate evaluation solution, and let it stand for 30 minute. Thereafter, the hydrogen peroxide decomposition rate evaluation liquid was stirred at a speed of 150 rpm with a stirrer, and a 0.1 mol/L sodium thiosulfate aqueous solution was added to the system using a biuret. Record the addition amount of 0.1 mol/L sodium thiosulfate aqueous solution when the hydrogen peroxide decomposition rate evaluation solution turns from red to white. Using this result, the residual amount of hydrogen peroxide was determined by the following formula. Residual amount of hydrogen peroxide (%)=0.1701×T×100/200 In addition, T represents the addition amount (g) of the 0.1 mol/L sodium thiosulfate aqueous solution. The evaluation criteria of the hydrogen peroxide decomposition rate test of the chemical mechanical polishing composition are as follows. Table 2 shows the residual amount of hydrogen peroxide and its evaluation results. (evaluation standard) · When the residual amount of hydrogen peroxide is 70% or more, it is judged to be good due to its practicality and marked as "A". · If the residual amount of hydrogen peroxide is less than 70%, it is judged to be inferior because it is not practical, and is marked as "B".

＜Evaluation of dispersibility of chemical mechanical polishing composition＞ Put 100 mL of the chemical mechanical polishing composition described in Table 2 into a polyethylene container, close the lid and airtightly, stir, and let it stand in a constant temperature bath at 40°C for 48 hours. Regarding the polyethylene container after being allowed to stand, observe after 24 hours and 48 hours have passed to confirm whether there is sedimentation. (evaluation standard) · If there is almost no settlement after 48 hours, mark it as "AA". ·After 24 hours, there is almost no settlement, but if some settlement is seen after 48 hours, it is marked as "A". · If a part of the settlement is seen after 24 hours, mark it as "B". · If a large amount of sedimentation is seen after 24 hours, mark it as "C".

4.4. Evaluation results Table 1 below shows the composition of each aqueous dispersion and the physical properties of abrasive grains contained in each aqueous dispersion. The following Table 2 shows the chemical mechanical polishing composition of each Example and each Comparative Example, and each evaluation result.

[Table 1] Types of aqueous dispersions A1 A2 A3 A4 A5 A6 A7 Abrasive species Abrasive A Abrasive B Abrasive C Abrasive D Abrasive E Abrasive F Abrasive A M _Al /M _Ti 0.04 0.04 0.04 0.05 0.04 0.04 0.04 M _Si /M _Ti 0.15 0.23 0.06 0.21 0.15 0.15 0.15 Average primary particle size (nm) 40 40 40 40 40 40 40 Fatty acid or fatty acid salt species Na stearate Na stearate Na stearate Na stearate Lauric acid Na Na oleic acid Na stearate Polyether compound species PEG-11 methyl ether dimethyl silicone PEG-11 methyl ether dimethyl silicone PEG-11 methyl ether dimethyl silicone PEG-11 methyl ether dimethyl silicone PEG-11 methyl ether dimethyl silicone PEG-11 methyl ether dimethyl silicone Polyoxyethylene sorbitan monooleate Types of aqueous dispersions A8 A9 A10 A11 B1 B2 B3 Abrasive species Abrasive A Abrasive A Abrasive A Abrasive G Abrasive H Abrasive Ⅰ Abrasive J M _Al /M _Ti 0.04 0.04 0.04 0.07 0 0 0.05 M _Si /M _Ti 0.15 0.15 0.15 0.28 0.34 0 0 Average primary particle size (nm) 40 40 40 20 40 40 40 Fatty acid or fatty acid salt species Na stearate Na stearate Na stearate Na stearate - - - Polyether compound species Polyoxyalkylene decyl ether Polyoxyethylene tridecyl ether Polyoxyethylene styrenated phenyl ether PEG-11 methyl ether dimethyl silicone PEG-11 methyl ether dimethyl silicone - PEG-11 methyl ether dimethyl silicone

[Table 2] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Example 10 Example 11 Comparative example 1 Comparative example 2 Comparative example 3 Composition for chemical mechanical polishing Aqueous dispersion A1 A2 A3 A4 A5 A6 A7 A8 A9 A10 A11 B1 B2 B3 Oxidant hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide hydrogen peroxide pH adjuster Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH Nitric acid/KOH pH 11 11 11 11 11 11 11 11 11 11 11 11 11 11 Evaluation item Ru grinding speed (nm/min) 319 339 320 321 417 314 352 336 330 331 329 342 224 228 A A A A A A A A A A A A B B SiO ₂ polishing speed (nm/min) 62 93 43 86 72 56 67 80 68 75 89 74 67 16 A A A A A A A A A A A A A B Defect evaluation 591 332 891 349 981 699 681 690 719 775 301 1401 2915 1491 B A B A B B B B B B A B B B Hydrogen peroxide decomposition (H ₂ O ₂ residual %) 90 90 90 89 60 89 86 89 85 91 91 63 3 90 A A A A B A A A A A A B B A Dispersion evaluation AA AA AA AA A AA AA AA AA AA A B C B

For each component in Table 2 above, the following products or reagents were used. ＜Oxidant＞ ·Hydrogen peroxide: manufactured by Wako Pure Chemical Industries, trade name "Hydrogen Peroxide" ＜pH adjuster＞ ·Ammonia: manufactured by Mitsubishi Gas Chemical Company, trade name "ultra-pure ammonia water"

It is known that in Examples 1 to 11, by using titanium oxide particles modified with aluminum oxide and silicon oxide as abrasive grains, it is excellent in the stability of the chemical mechanical polishing composition, and the ruthenium film And silicon oxide film for high-speed polishing.

Comparative Example 1 is an example of using a chemical mechanical polishing composition containing titanium oxide particles (abrasive grains H) that are not modified with aluminum oxide. In this case, blistering due to the reaction with hydrogen peroxide was found on the surface of the abrasive grain H. In addition, in the evaluation of dispersibility, it was found that a part of the abrasive grains H aggregated, and it was found that the stability was impaired.

Comparative Example 2 is an example of using a chemical mechanical polishing composition containing titanium oxide particles (abrasive grains I) that are not modified with aluminum oxide and silicon oxide. In this case, a large amount of blistering due to the reaction with hydrogen peroxide was observed on the surface of the abrasive grain I, and it was confirmed that the hydrogen peroxide had almost disappeared. Therefore, the polishing rate of the ruthenium film decreases. Furthermore, in the evaluation of dispersibility, it was found that the abrasive grains I aggregated, and it was found that the stability was impaired.

Comparative Example 3 is an example of using a chemical mechanical polishing composition containing titanium oxide particles (abrasive grains J) that are not modified with silicon oxide. In this case, it was confirmed that the polishing rate of both the ruthenium film and the silicon oxide film decreased. In addition, in the evaluation of dispersibility, it was found that a part of the abrasive grains J aggregated, and it was found that the stability was impaired.

The present invention is not limited to the above-mentioned embodiment, and various modifications can be made. For example, the present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations with the same functions, methods, and results, or configurations with the same purposes and effects). Furthermore, the present invention includes a configuration in which non-essential parts of the configuration described in the embodiment are replaced. In addition, the present invention includes a configuration that exhibits the same functions and effects as the configuration described in the embodiment or a configuration that can achieve the same object. Furthermore, the present invention includes a configuration obtained by adding a known technique to the configuration described in the embodiment.

10: Matrix 12: Silicon oxide film 14: Slot for wiring 16: Ruthenium film 18: Copper film 42: Slurry supply nozzle 44: Slurry (composition for chemical mechanical polishing) 46: Abrasive cloth 48: turntable 50: Semiconductor substrate 52: Carrier head 54: Water supply nozzle 56: Dresser 100: processed body 200: Grinding device

FIG. 1 is a cross-sectional view schematically showing a to-be-processed object suitable for using the polishing method of this embodiment. Fig. 2 is a cross-sectional view schematically showing the object to be processed at the end of the first polishing step. Fig. 3 is a cross-sectional view schematically showing the object to be processed at the end of the second polishing step. Fig. 4 is a perspective view schematically showing a chemical mechanical polishing apparatus.

Claims (13)

An abrasive grain made of aluminum oxide and silicon oxide modified titanium oxide particles. The abrasive grains are used to grind a substrate containing ruthenium, and the number of moles of titanium oxide in the abrasive grains is set to M _Ti and aluminum oxide. When the molar number of is set to M _Al and the molar number of silicon _{oxide is set to M Si} , _{the value of M Al} /M Ti is 0.004 or more and 2.35 or less, and _{the value of M Si} /M _Ti is 0.007 or more and 8.00 or less . The abrasive grain according to claim 1, wherein at least one selected from the group consisting of fatty acids and their salts is adsorbed or coated on at least a part of the outer layer of the abrasive grains. The abrasive grains according to claim 2, wherein the fatty acid and its salt are selected from the group consisting of caprylic acid, capric acid, lauric acid, myristic acid, isomyristic acid, palmitic acid, isopalmitic acid, stearic acid, and isostearic acid. At least one of fatty acid, arachidic acid, undecylenic acid, oleic acid, myristic acid, elaidic acid, linoleic acid, linolenic acid, arachidic acid and their salts. A kind of abrasive particles, made of aluminum oxide and silicon oxide modified titanium oxide particles, The abrasive grains are used to grind a substrate containing ruthenium, and at least one kind selected from the group consisting of fatty acids and their salts is adsorbed or coated on at least a part of the outer layer of the abrasive grains. The abrasive grains according to claim 4, wherein the fatty acid and its salt are selected from the group consisting of caprylic acid, capric acid, lauric acid, myristic acid, isomyristic acid, palmitic acid, isopalmitic acid, stearic acid, and isostearic acid. At least one of fatty acid, arachidic acid, undecylenic acid, oleic acid, myristic acid, elaidic acid, linoleic acid, linolenic acid, arachidic acid and their salts. A composition for chemical mechanical polishing, which contains the abrasive grains according to any one of claims 1 to 5. The chemical mechanical polishing composition according to claim 6, which further contains (B) a polyether compound. The chemical mechanical polishing composition according to claim 6, wherein the pH is 7 or more and 13 or less. The composition for chemical mechanical polishing according to claim 6, which further contains (C) an oxidizing agent. A chemical mechanical polishing composition used for polishing a substrate containing ruthenium and containing (A) abrasive grains formed by modifying titanium oxide particles with aluminum oxide and silicon oxide. The chemical mechanical polishing composition according to claim 10, which further contains (B) a polyether compound. The chemical mechanical polishing composition according to claim 10, wherein the pH is 7 or more and 13 or less. The composition for chemical mechanical polishing according to claim 10, which further contains (C) an oxidizing agent.

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