TW202022082A - Aqueous dispersion for chemical mechanical polishing and method of producing the same, and chemical mechanical polishing method - Google Patents

Abstract

To provide an aqueous dispersion for chemical mechanical polishing allowing for high-speed polishing of a substrate including a plurality of materials such as a wiring material, an insulating film material, and a barrier metal material while suppressing corrosion of the wiring material and the like, and a method of producing the aqueous dispersion for chemical mechanical polishing. The method of producing the aqueous dispersion for chemical mechanical polishing according to the present invention includes a step (I) of hydrolyzing and condensing silicon alkoxide in an aqueous medium including a tertiary amine compound, a step (IV) of further dropping silicon alkoxide into the aqueous medium, and growing colloidal silica abrasive grains having a zeta potential of +1 mV or more and +5 mV or less, and a step (V) of, after the step (IV), adding to the aqueous medium, an amine compound, and at least one selected from the group consisting of metal nitrates and metal sulfates.

Description

Chemical mechanical polishing water-based dispersion, its manufacturing method, and chemical mechanical polishing method

The present invention relates to a chemical mechanical polishing aqueous dispersion, a manufacturing method thereof, and a chemical mechanical polishing method.

Chemical mechanical polishing (Chemical Mechanical Polishing, CMP) has shown rapid spread in planarization techniques in the manufacture of semiconductor devices. In this CMP, the object to be polished is pressed against the polishing pad, and an aqueous dispersion of chemical mechanical polishing is supplied to the polishing pad while sliding the object to be polished and the polishing pad to chemically and mechanically polish the object to be polished. technology.

In recent years, with the advancement of high-definition semiconductor devices, the miniaturization of wiring layers including wiring, plugs, and the like formed in semiconductor devices is progressing. Along with this, a method of planarizing the wiring layer by CMP is used. The substrate of the semiconductor device includes: an insulating film material; a wiring material; a barrier metal material for preventing the wiring material from diffusing into the inorganic material film, and the like. Here, the insulating film material mainly uses silicon dioxide, the wiring material mainly uses copper or tungsten, and the barrier metal material mainly uses tantalum nitride or titanium nitride.

In order to polish such insulating film materials, wiring materials, barrier metal materials, etc. at a high speed, for example, Patent Document 1 discloses a chemical composition containing silicon dioxide abrasive grains with a permanent positive charge of 6 mV or more, amine compounds, and iron nitrate. Mechanically grind the composition. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Publication No. 2017-514295

[Problems to be solved by the invention]

The chemical mechanical polishing composition described in Patent Document 1 improves the dispersion stability of the abrasive particles and improves the polishing characteristics of the tungsten substrate by setting the surface of the abrasive particles to a stable positive charge. It is presumed that the reason is that by using abrasive grains with a high value of Zeta potential, the electrostatic repulsive force suppresses aggregation, and the adhesion effect to the tungsten substrate is significantly exhibited. However, in addition to wiring materials such as tungsten, a wiring substrate used in a semiconductor device also contains silicon dioxide or the like as an insulating film material or titanium nitride as a barrier metal material. Moreover, when polishing such insulating film materials, etc., the chemical mechanical polishing composition described in Patent Document 1 has a problem that it is difficult to perform high-speed polishing.

Therefore, several aspects of the present invention provide a chemical mechanical polishing aqueous dispersion and a method of manufacturing the same, which can suppress corrosion of wiring materials and the like, and simultaneously polish at high speeds containing wiring materials, Substrates made of various materials such as insulating film materials and barrier metal materials. In addition, some aspects of the present invention provide an aqueous dispersion for chemical mechanical polishing with improved dispersion stability of abrasive grains and a method for producing the same. [Means to solve the problem]

The present invention is designed 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 method for producing an aqueous dispersion for chemical mechanical polishing of the present invention is the following method for producing an aqueous dispersion for chemical mechanical polishing, which contains: colloidal silica abrasive grains, amine The compound and at least one selected from the group consisting of metal nitrates and metal sulfates, and the manufacturing method of the chemical mechanical polishing aqueous dispersion includes: Step (I), hydrolyze and condense the silane oxide in an aqueous medium with tertiary amine compounds; Step (IV), after the step (I), add silanic oxide dropwise to the aqueous medium to make the zeta potential of colloidal silica with a zeta potential of +1 mV or more and +5 mV or less Abrasive grain growth; and Step (V), after the step (IV), add an amine compound and at least one selected from the group consisting of metal nitrates and metal sulfates to the aqueous medium.

In one aspect of the manufacturing method of the chemical mechanical polishing aqueous dispersion, it may further include: step (II), after the step (I) and before the step (IV), the aqueous medium Concentrate and remove alcohol content.

In any aspect of the manufacturing method of the chemical mechanical polishing aqueous dispersion, it may further include: step (III), after the step (I) and before the step (IV), to the water system Add tertiary amine to the medium.

In any aspect of the manufacturing method of the chemical mechanical polishing aqueous dispersion, it may further include: step (VI), after the step (V), adding hydrogen peroxide.

In any aspect of the method for producing the aqueous dispersion for chemical mechanical polishing, the aqueous dispersion for chemical mechanical polishing can be used in the group consisting of tungsten, silicon dioxide, and titanium nitride More than one kind of substrate polishing.

One aspect of the chemical mechanical polishing aqueous dispersion of the present invention contains: (A) Colloidal silica abrasive particles with a permanent positive charge above +1 mV and below +5 mV; (B) At least one selected from the group consisting of metal nitrates and metal sulfates; (C) At least one selected from the group consisting of amine compounds and their salts; and (D) Chelating agents other than the aforementioned (C) component, and The pH is 1 or more and 3 or less.

In one aspect of the aqueous dispersion for chemical mechanical polishing, a tertiary amine compound may be contained in the colloidal silica abrasive grains.

In any aspect of the aqueous dispersion for chemical mechanical polishing, the tertiary amine compound may be contained in the colloidal silica abrasive grains.

In any aspect of the aqueous dispersion for chemical mechanical polishing, it can be used for polishing substrates containing more than one selected from the group consisting of tungsten, silicon dioxide, and titanium nitride.

One aspect of the chemical mechanical polishing method of the present invention includes: using any aspect of the chemical mechanical polishing aqueous dispersion to contain one selected from the group consisting of tungsten, silicon dioxide, and titanium nitride The above substrate is polished. [Effect of invention]

According to the aqueous dispersion for chemical mechanical polishing of the present invention, it is possible to polish a substrate containing a variety of materials such as wiring materials, insulating film materials, barrier metal materials and the like while suppressing corrosion of wiring materials and the like. In addition, according to the chemical mechanical polishing aqueous dispersion of the present invention, the dispersion stability of abrasive grains becomes better.

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 modified examples implemented within a scope that does not change the gist of the present invention.

In this manual, the numerical range described in "～" includes the numerical values described before and after "～" as the lower limit and the upper limit.

The so-called "wiring material" refers to conductive metal materials such as aluminum, copper, cobalt, titanium, ruthenium, and tungsten. The so-called "insulating film material" refers to materials such as silicon dioxide, silicon nitride, and amorphous silicon. The so-called "barrier metal material" refers to materials such as tantalum nitride and titanium nitride that are laminated with wiring materials for the purpose of improving wiring reliability.

1. Manufacturing method of chemical mechanical polishing aqueous dispersion The production method of the chemical mechanical polishing aqueous dispersion of this embodiment is a method for producing the following chemical mechanical polishing aqueous dispersion, the chemical mechanical polishing aqueous dispersion containing: colloidal silica abrasive grains, amine compound , And at least one selected from the group consisting of metal nitrates and metal sulfates. The manufacturing method of the chemical mechanical polishing aqueous dispersion of this embodiment includes: step (I), hydrolyzing and condensing silane oxide in an aqueous medium in which a tertiary amine compound exists; step (IV), in the step ( I) After that, silane oxide is added dropwise to the aqueous medium to grow colloidal silica abrasive grains with a cheek potential of +1 mV or more and +5 mV or less; and step (V), in the step After (IV), an amine compound and at least one selected from the group consisting of metal nitrates and metal sulfates are added to the aqueous medium. Hereinafter, each step included in the manufacturing method of the chemical mechanical polishing aqueous dispersion of this embodiment is described in detail.

1.1. Steps (I) In step (I), the silane oxide is hydrolyzed and condensed in an aqueous medium in which a tertiary amine compound is present. Specifically, when the water-based medium is set to 100 parts by mass, 0.03 parts by mass or more and 2 parts by mass or less of the tertiary amine compound are added, and after sufficient stirring, 1.4 parts by mass or more and 50 parts by mass or less of silicon alkoxide are added. , And hydrolyze and condense at a temperature above 25°C and below 100°C. In this way, an aqueous dispersion containing colloidal silica abrasive grains can be obtained.

Examples of tertiary amine compounds include: triethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N-methyldiethanolamine, N-butyldiethanolamine, trimethylamine, and triethyl Amine, tripropylamine, tributylamine, dimethylglycine and tetramethylethylenediamine. Among these, triethanolamine and N,N-dimethylethanolamine are preferred, and triethanolamine is more preferred.

When the aqueous medium before the addition of the tertiary amine compound is 100 parts by mass, the lower limit of the addition amount of the tertiary amine compound is preferably 0.03 part by mass, more preferably 0.1 part by mass, and particularly preferably 0.3 part by mass. On the other hand, the upper limit of the addition amount of the tertiary amine compound is preferably 2 parts by mass, more preferably 1 part by mass, and particularly preferably 0.6 part by mass. If the addition amount of the tertiary amine compound is within the above-mentioned range, it is easy to adjust the obtained silicon dioxide abrasive grains to have a potential of +1 mV or more and +5 mV or less.

In the operation of adding the silane oxide to the aqueous medium, it is preferable to prepare a mixed liquid of the silane oxide and alcohol, and slowly drop the mixed liquid into the aqueous medium. By doing this, an aqueous dispersion containing colloidal silica abrasive grains of uniform particle size in an aqueous medium can be obtained. After the silane oxide is added, hydrolysis and condensation can be carried out under temperature conditions of preferably 25°C or higher and 100°C or lower, more preferably 50°C or higher and 95°C or lower. By performing hydrolysis and condensation within the temperature range, it is easy to produce colloidal silica abrasive grains with excellent dispersibility.

Examples of silane oxides include tetramethoxysilane, tetraethoxysilane, allyltriethoxysilane, benzyltriethoxysilane, 1,2-bis(trimethoxysilyl) Ethane, cyclopentyltrimethoxysilane, decyltrimethoxysilane, decyltriethoxysilane, and cyclohexyl(dimethoxy)methylsilane. Among these, tetramethoxysilane and tetraethoxysilane are preferred, and tetramethoxysilane is particularly preferred. In the case of such a silane oxide, the obtained colloidal silica abrasive grains have moderate hardness, and the polishing characteristics of wiring materials such as tungsten are excellent.

When the aqueous medium before the addition of the tertiary amine compound is 100 parts by mass, the lower limit of the addition amount of the silane oxide is preferably 1.4 parts by mass, more preferably 5 parts by mass, and particularly preferably 10 parts by mass. On the other hand, the upper limit of the addition amount of the silane oxide is preferably 50 parts by mass, more preferably 40 parts by mass, and particularly preferably 20 parts by mass. If the addition amount of the silane oxide is within the above-mentioned range, the interaction with the tertiary amine compound makes it easy to adjust the obtained colloidal silica abrasive grains to a potential of +1 mV or more and +5 mV. the following.

1.2. Step (II) Then, it is preferable to perform step (II): after the step (I) and before the step (IV) described later, the aqueous dispersion containing colloidal silica abrasive grains obtained in the step (I) is concentrated and Remove the alcohol component. Step (II) is more preferably performed after step (I) and before step (III) described later.

Step (II) is performed as follows: for example, using an evaporator while adding water while removing the alcohol component. Thereby, an aqueous dispersion containing colloidal silica abrasive grains from which the alcohol component has been removed can be obtained. By going through step (II), it is easy to adjust the cheek potential of the obtained colloidal silica abrasive grains to +1 mV or more and +5 mV or less.

1.3. Step (III) Then, it preferably includes step (III), after the step (I) and before the step (IV) described later, further adding a tertiary amine compound to the aqueous dispersion. Step (III) is more preferably performed after the step (II) and before the step (IV) described later.

By further adding a tertiary amine compound to the aqueous dispersion, the tertiary amine compound and the silane oxide are likely to interact with each other, so it is easy to adjust the obtained colloidal silica abrasive grains to +1 mV or more and +5 mV or less, and it is easy to produce colloidal silica abrasive grains with excellent abrasive properties.

As the tertiary amine compound added in step (III), it is preferable to be the same kind as the tertiary amine compound added in step (I), or a different kind. When the aqueous dispersion obtained in step (I) is set to 100 parts by mass, the lower limit of the amount of tertiary amine compound added in step (III) is preferably 0.03 parts by mass, more preferably 0.3 parts by mass . On the other hand, the upper limit of the addition amount of the tertiary amine compound added in step (III) is preferably 1 part by mass, more preferably 0.8 part by mass.

1.4. Step (IV) Then, in step (IV), after the step (I), silane oxide is added dropwise to the aqueous dispersion to make the colloidal dioxide with a cheek potential of +1 mV or more and +5 mV or less Silicon abrasive grains grow. By passing through step (IV), the colloidal silica abrasive grains obtained in step (I) can be grown, and an aqueous dispersion containing colloidal silica abrasive grains with excellent abrasive properties can be produced.

As the silicon alkoxide added in step (IV), it is preferable to add the same kind of silicon alkoxide as in the step (I), or a different kind. When the aqueous dispersion obtained in step (I) is set to 100 parts by mass, the lower limit of the addition amount of the silane oxide added in step (IV) is preferably 5 parts by mass, more preferably 10 parts by mass. On the other hand, the upper limit of the addition amount of the silane oxide added in step (IV) is preferably 40 parts by mass, more preferably 25 parts by mass.

Furthermore, it is preferable that the manufacturing method of the chemical mechanical polishing aqueous dispersion of this embodiment performs step (I), step (II), step (III), and step (IV) in order. Furthermore, if steps (II) to (IV) are performed multiple times, the tertiary amine compound and the silane oxide are likely to interact with each other. Therefore, there is a situation in which it is easy to change the differential potential of the obtained colloidal silica abrasive grains. It is adjusted to +1 mV or more and +5 mV or less, and it is easy to produce colloidal silica abrasive grains with excellent abrasive properties.

1.5. Steps (V) Then, in step (V), after step (IV), an amine compound is added to the aqueous dispersion containing the colloidal silica abrasive grains, and is selected from the group consisting of metal nitrates and metal sulfates At least one of them. By going through step (V), the chemical mechanical polishing aqueous dispersion invented in this application can be obtained. The chemical mechanical polishing aqueous dispersion of the invention of the present application can suppress the corrosion of wiring materials while simultaneously polishing substrates containing various materials such as wiring materials, insulating film materials, and barrier metal materials at high speed. In addition, the chemical mechanical polishing aqueous dispersion invented in this application can improve the dispersion stability of colloidal silica abrasive particles.

As the amine compound added in step (V), for example, polynitrogen-containing compounds such as 2-aminoethylpiperazine, 1,4-bis(3-aminopropyl)piperazine, and triethylenetetramine Compounds; amphoteric surfactants such as sodium laurylamine dipropionate, N-lauryl-N'-carboxymethyl-N'-hydroxyethylethylenediamine sodium; cationic polymers such as polyethyleneimine. Among these, preferred are amphoteric surfactants and cationic polymers, and particularly preferred are carboxyl-containing betaine-type amphoteric surfactants with a carbon chain of 12 or more (except for amino carboxylic acids). If it is a chemical mechanical polishing aqueous dispersion containing such an amine compound, the corrosion of the wiring material can be suppressed, and the dispersion stability of the colloidal silica abrasive grains in the aqueous dispersion can be improved.

When the aqueous medium after step (IV) is set to 100 parts by mass, the lower limit of the amount of the amine compound added is preferably 0.001 parts by mass, more preferably 0.01 parts by mass. On the other hand, the upper limit of the addition amount of the amine compound is preferably 1 part by mass, more preferably 0.5 part by mass.

Examples of the metal nitrate added in step (V) include copper nitrate, cobalt nitrate, zinc nitrate, manganese nitrate, iron nitrate, molybdenum nitrate, bismuth nitrate, and cerium nitrate. Examples of the metal sulfate added in step (V) include copper sulfate, cobalt sulfate, zinc sulfate, manganese sulfate, iron sulfate, silver sulfate, and the like. Among these, it is preferably at least one selected from the group consisting of copper nitrate, iron nitrate, copper sulfate and iron sulfate, and more preferably at least one selected from the group consisting of iron nitrate and iron sulfate. These compounds have particularly high oxidizing power in metal nitrates and metal sulfates, and therefore can passivate the surface of the wiring material or barrier metal material to form an oxide layer. Moreover, the oxide layer can be removed at high speed by using the mechanical polishing action of colloidal silica abrasive grains.

When the aqueous medium after step (IV) is set to 100 parts by mass, the lower limit of the addition amount of at least one selected from the group consisting of metal nitrates and metal sulfates is preferably 0.001 parts by mass, and more Preferably it is 0.01 part by mass. On the other hand, the upper limit of the addition amount of at least one selected from the group consisting of metal nitrates and metal sulfates is preferably 1 part by mass, more preferably 0.5 part by mass.

1.6. Step (VI) Then, step (VI) may also be included: after step (V), hydrogen peroxide is added to the chemical mechanical polishing aqueous dispersion obtained in step (V). By using the metal sulfate and/or metal nitrate added in step (V) together with hydrogen peroxide, there are cases where a strong oxidation reaction (Fenton reaction) is caused, and the wiring material or Position barrier metal material. Hydrogen peroxide is unstable, easily releases oxygen, and easily generates hydroxyl radicals with very strong oxidizing power. Therefore, it is better to perform step (VI) immediately before CMP.

When the chemical mechanical polishing aqueous dispersion obtained in step (V) is set to 100 parts by mass, the lower limit of the amount of hydrogen peroxide added is preferably 0.001 parts by mass, more preferably 0.005 parts by mass, and particularly preferably 0.01 parts by mass. On the other hand, with respect to the total mass of the chemical mechanical polishing aqueous dispersion obtained in step (V), the upper limit of the amount of hydrogen peroxide added is preferably 5 parts by mass, more preferably 3 parts by mass, particularly preferred It is 1.5 parts by mass.

2. Chemical mechanical polishing water-based dispersion The chemical mechanical polishing aqueous dispersion of this embodiment can be manufactured by the above-mentioned manufacturing method, but is not limited to the one manufactured by the above-mentioned manufacturing method. The chemical mechanical polishing aqueous dispersion of this embodiment contains: (A) colloidal silica abrasive grains (also referred to as "component (A)") having a permanent positive charge of +1 mV or more and +5 mV or less; B) At least one selected from the group consisting of metal nitrates and metal sulfates (also called "(B) component"); (C) At least one selected from the group consisting of amine compounds and their salts One (also referred to as "(C) component"); and (D) chelating agents other than the (C) component (also referred to as "(D) component"), and the pH is 1 or more and 3 or less. Hereinafter, each component contained in the chemical mechanical polishing aqueous dispersion of this embodiment will be described in detail.

2.1. (A) Colloidal silica abrasive particles The chemical mechanical polishing aqueous dispersion of the present embodiment contains (A) colloidal silica abrasive grains having a permanent positive charge of +1 mV or more and +5 mV or less. As one of the functions of the (A) component, it is possible to exemplify the mechanical polishing of a substrate containing various materials such as wiring materials, insulating film materials, barrier metal materials, and the like to increase the polishing speed. In particular, it is possible to increase the polishing rate of a substrate containing tungsten as a wiring material, silicon dioxide as an insulating film material, and titanium nitride as a barrier metal material.

Here, the term "colloidal silica abrasive grains with permanent positive charge" refers to adding ion-exchanged water so that the colloidal silica abrasive grains become 1% by mass (using the model "Demisu ( Demi Ace) DZ-50C" is obtained by ion-exchange treatment of water), and the aqueous dispersion of colloidal silica abrasive grains with pH adjusted to 2.4 is made in Entegris (Entegris) company made 0.3 μm pore diameter polypropylene The change in the absolute value of the zeta potential before and after the filter (model Planargard PCL0301E6) through the filter (model Planargard PCL0301E6) is 4 mV or less colloidal silica abrasive particles. In addition, as the absolute value of the cheek potential of the colloidal silica abrasive grain after passing through three times, it is preferably 3 mV or less, and more preferably 1 mV or less. That is, the so-called "(A) colloidal silica abrasive grains with a permanent positive charge of +1 mV or more and +5 mV or less" means that before and after the three filtrations, the other potential is +1 mV or more and +5 mV or less, and the change in absolute value of the cheek potential before and after filtration is 4 mV or less colloidal silica abrasive grains.

If it is a colloidal silica abrasive grain with a permanent positive charge within the above range, the polishing speed of substrates including wiring materials, insulating film materials, barrier metal materials and other materials can be increased, and in particular, it can be increased The polishing rate of materials such as tungsten, silicon dioxide as an insulating film material, and titanium nitride as a barrier metal material. In addition, if it is colloidal silica abrasive grains having a permanent positive charge within the above-mentioned range, the dispersion stability is also likely to become good.

In addition, as the component (A), colloidal silica abrasive grains containing a tertiary amine compound are preferred, and colloidal silica abrasive grains containing a tertiary amine compound are more preferred. The tertiary amine compound is contained in the colloidal silica abrasive grains, and the component (A) easily has a permanent positive charge of +1 mV or more and +5 mV or less, so it is easy to increase the inclusion of wiring materials, insulating film materials and potential barriers Polishing speed of substrates of various materials such as metal materials.

Examples of tertiary amine compounds include: triethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N-methyldiethanolamine, N-butyldiethanolamine, trimethylamine, and triethyl Amine, tripropylamine, tributylamine, dimethylglycine and tetramethylethylenediamine. Among these, triethanolamine and N,N-dimethylethanolamine are preferred, and triethanolamine is more preferred.

The manufacturing method of (A) component is not specifically limited, It can manufacture suitably by the manufacturing method of the colloidal silica abrasive grain containing said step (I) to said step (IV).

(A) The average particle diameter of the component is preferably 5 nm or more and 300 nm or less. If the average particle size of the component (A) is within the above range, there are cases in which it is possible to improve the polishing of various materials such as wiring materials, insulating film materials, and barrier metal materials while suppressing polishing damage on the polished surface. speed. Here, in the above-mentioned range, the (A) component having an average particle diameter in the range of 10 nm or more and 150 nm or less may particularly increase the polishing rate. In addition, in the above-mentioned range, the component (A) having an average particle diameter in the range of 10 nm or more and 100 nm or less can particularly suppress the generation of polishing damage on the surface to be polished. Here, the average particle diameter of (A) component can be calculated|required by the following method: It measures by the particle size distribution measuring apparatus which uses a dynamic light scattering method as a measuring principle. Examples of the particle size measuring device using the dynamic light scattering method include the dynamic light scattering particle size distribution measuring device "LB-550" manufactured by Horiba Manufacturing Co., Ltd., and the Beckman-Coulter (Beckman-Coulter) Co. Rice abrasive particle analyzer "Delsa Nano S", "Zetasizernano zs" manufactured by Malvern Company, etc. In addition, the average particle diameter measured using the dynamic light scattering method represents the average particle diameter of the secondary particles formed by agglomeration of a plurality of primary particles.

With respect to the total mass of the chemical mechanical polishing aqueous dispersion, the lower limit of the content of the component (A) is preferably 0.05% by mass, more preferably 0.1% by mass, and particularly preferably 0.3% by mass. If the content of the component (A) is greater than or equal to the lower limit, the polishing rate of a substrate containing a plurality of materials may be increased. On the other hand, with respect to the total mass of the chemical mechanical polishing aqueous dispersion, the upper limit of the content of the component (A) is preferably 10% by mass, more preferably 5% by mass, and particularly preferably 3% by mass. If the content of the component (A) is less than or equal to the upper limit, the dispersion stability is likely to become good, and the flatness of the polished surface or the reduction of polishing damage may be achieved in the chemical mechanical polishing step.

2.2. Metal nitrate, metal sulfate The chemical mechanical polishing aqueous dispersion of this embodiment contains (B) at least one selected from the group consisting of metal nitrates and metal sulfates. As one of the functions of the component (B), an oxide layer is formed on the surface of a substrate including various materials such as wiring materials, insulating film materials, and barrier metal materials, and the polishing rate is increased. Among these materials, in particular, the polishing speed of a substrate containing tungsten as a wiring material can be increased.

Examples of metal nitrates include copper nitrate, cobalt nitrate, zinc nitrate, manganese nitrate, iron nitrate, molybdenum nitrate, bismuth nitrate, and cerium nitrate. Examples of metal sulfates include copper sulfate, cobalt sulfate, zinc sulfate, manganese sulfate, iron sulfate, silver sulfate, and the like. Among these, it is preferably at least one selected from the group consisting of copper nitrate, iron nitrate, copper sulfate and iron sulfate, and more preferably at least one selected from the group consisting of iron nitrate and iron sulfate. These compounds have particularly high oxidizing power in metal nitrates and metal sulfates, and therefore can passivate the surface of the wiring material or barrier metal material to form an oxide layer. Moreover, the oxide layer can be removed at high speed by using the mechanical polishing action of colloidal silica abrasive grains.

The lower limit of the content of the component (B) is preferably 0.001% by mass, more preferably 0.01% by mass relative to the total mass of the aqueous dispersion for chemical mechanical polishing. On the other hand, the upper limit of the content of the component (B) is preferably 1% by mass, more preferably 0.5% by mass. If the content of the (B) component is in the above range, the polishing rate for a substrate including a variety of materials such as wiring materials, insulating film materials, and barrier metal materials will increase. In particular, the polishing speed of a substrate containing tungsten as a wiring material is increased.

2.3. (C) Amine compounds and their salts The chemical mechanical polishing aqueous dispersion of this embodiment contains (C) at least one selected from the group consisting of amine compounds and their salts. As one of the functions of the component (C), the suppression of corrosion of wiring materials and the like can be cited. In particular, corrosion of a substrate containing tungsten as a wiring material can be suppressed. In addition, as another function of the component (C), the dispersion stability of the component (A) in the chemical mechanical polishing aqueous dispersion is improved.

The component (C) is not particularly limited as long as it is a compound containing an amine. Examples include 2-aminoethylpiperazine, 1,4-bis(3-aminopropyl)piperazine, and triethylenetetramine Amines and other polynitrogen-containing compounds; amphoteric surfactants such as sodium laurylamine dipropionate, N-lauryl-N'-carboxymethyl-N'-hydroxyethyl ethylenediamine sodium (among them, the amine Except for carboxylic acid); cationic polymers such as polyethyleneimine. Among these, amphoteric surfactants and cationic polymers are preferred, and carboxyl-containing betaine-type amphoteric surfactants having a carbon chain of 12 or more are particularly preferred. If it is a chemical mechanical polishing aqueous dispersion containing such an amine compound, the corrosion of the wiring material can be suppressed, and the dispersion stability of the colloidal silica abrasive grains in the aqueous dispersion can be improved. (C) The component may be used singly or in combination of two or more in any ratio.

As a specific example of the salt of an amine compound, the salt of the said exemplified amine compound may be sufficient, and the salt of an amine compound may be reacted with the additive added separately to the aqueous dispersion of chemical mechanical polishing.

The lower limit of the content of the component (C) is preferably 0.001% by mass, more preferably 0.01% by mass relative to the total mass of the aqueous dispersion for chemical mechanical polishing. On the other hand, the upper limit of the content of the component (C) is preferably 1% by mass, more preferably 0.5% by mass. If the content of the component (C) is in the above range, the corrosion of wiring materials and the like can be suppressed more effectively.

2.4. (D) Chelating agent The chemical mechanical polishing aqueous dispersion of this embodiment contains a chelating agent other than the (D) component (C). As one of the functions of the (D) component, it is possible to increase the polishing speed of a substrate including a variety of materials such as wiring materials, insulating film materials, and barrier metal materials. In particular, it is possible to increase the polishing speed of a substrate containing tungsten as a wiring material.

The component (D) is not particularly limited as long as it is a compound having a chelating effect, and it is preferably at least one selected from the group consisting of organic acids and their salts.

Examples of such organic acids include phosphonic acids, 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, p-hydroxybenzoic acid, quinolinic acid, quinaldic acid (quinaldic acid), amide sulfuric acid; glycine, alanine, aspartic acid, glutamine, lysine Acid (lysine), arginine, tryptophan, arginine, histidine, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid and other amino carboxylic acids. Among these, it is preferably at least one selected from the group consisting of phosphonic acid, maleic acid, succinic acid, lactic acid, malonic acid, and amino carboxylic acid, and more preferably selected from the group consisting of malonic acid, 1- At least one of the group consisting of hydroxyethylene-1,1-diphosphonic acid and diethylenetriaminepentaacetic acid, particularly preferably malonic acid. Such organic acids may be used alone or in combination of two or more in any ratio.

As a specific example of the salt of an organic acid, the salt of the said organic acid may be sufficient, and it may react with the base added separately in the aqueous dispersion of chemical mechanical polishing, and may form the salt of the said organic acid. Examples of such bases include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide, organic bases such as tetramethyl ammonium hydroxide (TMAH) and choline. Compounds, and ammonia, etc.

The lower limit of the content of the component (D) is preferably 0.001 part by mass, more preferably 0.01 part by mass relative to the total mass of the aqueous dispersion for chemical mechanical polishing. On the other hand, the upper limit of the content of the component (D) is preferably 1 part by mass, more preferably 0.5 part by mass. If the content of the (D) component is within the above-mentioned range, the polishing rate of a substrate including a variety of materials such as wiring materials, insulating film materials, and barrier metal materials will increase.

2.5. Other ingredients The chemical mechanical polishing aqueous dispersion of the present embodiment may contain water as the main liquid medium, and may also contain water-soluble polymers, oxidizing agents, surfactants, nitrogen-containing heterocyclic compounds, pH adjusters, etc. as necessary.

＜Water＞ The chemical mechanical polishing aqueous dispersion 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 material of the chemical mechanical polishing aqueous dispersion, and the content of water is not particularly limited.

＜Water-soluble polymer＞ The chemical mechanical polishing aqueous dispersion of this embodiment may contain a water-soluble polymer. By containing a water-soluble polymer, it can be adsorbed to the polished surface of the wiring material etc., and the polishing friction may be reduced. The water-soluble polymer is preferably a polycarboxylic acid, and more preferably at least one selected from the group consisting of polyacrylic acid, polymaleic acid, and copolymers of these acids.

The weight average molecular weight (Mw) of the water-soluble polymer is preferably 1,000 or more and 1,000,000 or less, more preferably 3,000 or more and 800,000 or less. If the weight average molecular weight of the water-soluble polymer is in the above-mentioned range, it is likely to be adsorbed on the surface to be polished such as a wiring material, which may further reduce polishing friction. As a result, it is possible to more effectively reduce the occurrence of polishing damage on the surface to be polished. In addition, the "weight average molecular weight (Mw)" in this specification refers to the weight average molecular weight in terms of polyethylene glycol measured by Gel Permeation Chromatography (GPC).

When the chemical mechanical polishing aqueous dispersion of this embodiment contains a water-soluble polymer, the content of the water-soluble polymer is preferably 0.01% by mass to 1% by mass relative to the total mass of the chemical mechanical polishing aqueous dispersion , More preferably 0.03% by mass to 0.5% by mass.

Furthermore, although the content of the water-soluble polymer also depends on the weight average molecular weight (Mw) of the water-soluble polymer, it is preferably adjusted so that the viscosity of the chemical mechanical polishing aqueous dispersion becomes less than 10 mPa·s . If the viscosity of the chemical mechanical polishing aqueous dispersion is less than 10 mPa·s, it is easy to grind wiring materials and the like at a high speed, and since the viscosity is appropriate, the chemical mechanical polishing aqueous dispersion can be stably supplied to the polishing cloth.

<Oxidant> The chemical mechanical polishing aqueous dispersion of this embodiment may contain an oxidizing agent different from the component (B). By containing an oxidizing agent different from the component (B), the wiring material or the like is oxidized and the complex reaction with the polishing liquid component is promoted, whereby a fragile modified layer can be formed on the polished surface, so polishing may be easy.

Examples of the oxidizing agent include ammonium persulfate, hydrogen peroxide, potassium hypochlorite, ozone, potassium periodate, and peracetic acid. Among these oxidants, at least one selected from potassium periodate, potassium hypochlorite and hydrogen peroxide is preferred, and hydrogen peroxide is more preferred. These oxidants can be used alone or in combination of two or more.

In the case where the chemical mechanical polishing aqueous dispersion of this embodiment contains an oxidizing agent, the content of the oxidizing agent is preferably 0.001 mass% to 5 mass%, and more preferably 0.005 mass% relative to the total mass of the chemical mechanical polishing aqueous dispersion % To 3% by mass, particularly preferably 0.01% to 1.5% by mass. Furthermore, when hydrogen peroxide is added as an oxidizing agent, hydrogen peroxide is unstable and easily releases oxygen, and it is easy to generate hydroxyl radicals with very strong oxidizing power. Therefore, it is preferable to add it immediately before CMP.

＜Surface active agent＞ The chemical mechanical polishing aqueous dispersion of this embodiment may contain surfactants other than the surfactants exemplified above. By containing a surfactant, it may be possible to impart appropriate viscosity to the chemical mechanical polishing aqueous dispersion.

The surfactant is not particularly limited, and examples include anionic surfactants, cationic surfactants, and nonionic surfactants. Examples of anionic surfactants include carboxylates such as fatty acid soaps and alkyl ether carboxylates; sulfonates such as alkylbenzene sulfonates, alkylnaphthalene sulfonates, and α-olefin sulfonates; Sulfates such as higher alcohol sulfates, alkyl ether sulfates, polyoxyethylene alkylphenyl ether sulfates; fluorine-containing surfactants such as perfluoroalkyl compounds, etc. As a cationic surfactant, aliphatic amine salt, aliphatic ammonium salt, etc. are mentioned, for example. Examples of nonionic surfactants include nonionic surfactants having triple bonds such as acetylene glycol, acetylene glycol ethylene oxide adduct, and acetylene alcohol; polyethylene glycol type surfactants, etc. . These surfactants can be used alone or in combination of two or more.

When the chemical mechanical polishing aqueous dispersion of this embodiment contains a surfactant, the content of the surfactant is preferably 0.001 mass% to 5 mass% relative to the total mass of the chemical mechanical polishing aqueous dispersion, and more It is preferably 0.001% by mass to 3% by mass, particularly preferably 0.01% by mass to 1% by mass.

＜Nitrogen-containing heterocyclic compounds＞ The chemical mechanical polishing aqueous dispersion of this embodiment may contain a nitrogen-containing heterocyclic compound. By containing the nitrogen-containing heterocyclic compound, there are situations in which excessive etching of the wiring material can be suppressed and surface roughness after polishing can be prevented.

In the present specification, the "nitrogen-containing heterocyclic compound" refers to an organic compound containing at least one heterocyclic ring selected from a hetero five-membered ring and a hetero six-membered ring having at least one nitrogen atom. Examples of the heterocyclic ring include hetero five-membered rings such as a pyrrole structure, an imidazole structure, and a triazole structure; and a hetero six-membered ring such as a pyridine structure, a pyrimidine structure, a pyridazine structure, and a pyrazine structure. These heterocyclic rings may also form condensed rings. Specifically, examples include indole structure, isoindole structure, benzimidazole structure, benzotriazole structure, quinoline structure, isoquinoline structure, quinazoline structure, cinnoline structure, phthalazine (Phthalazine) structure, quinoxaline structure, acridine structure, etc. Among the heterocyclic compounds having such a structure, a heterocyclic compound having a pyridine structure, a quinoline structure, a benzimidazole structure, or a benzotriazole structure is preferable.

Specific examples of nitrogen-containing heterocyclic compounds include: aziridine, pyridine, pyrimidine, pyrrolidine, piperidine, pyrazine, triazine, pyrrole, imidazole, indole, quinoline, isoquinoline, and benziso Quinoline, purine, pteridine, triazole, triazolidine, benzotriazole, carboxybenzotriazole, etc., and derivatives having these skeletons can be further cited. Among these, benzotriazole, triazole, imidazole, and carboxybenzotriazole are preferred. These nitrogen-containing heterocyclic compounds may be used alone or in combination of two or more.

When the chemical mechanical polishing aqueous dispersion of this embodiment contains a nitrogen-containing heterocyclic compound, the content of the nitrogen-containing heterocyclic compound is preferably 0.05% by mass to 2 relative to the total mass of the chemical mechanical polishing aqueous dispersion % By mass, more preferably 0.1% by mass to 1% by mass, particularly preferably 0.2% by mass to 0.6% by mass.

＜pH adjuster＞ In order to adjust pH to 1 or more and 3 or less, the chemical mechanical polishing aqueous dispersion of this embodiment may contain a pH adjuster. By containing the pH adjuster, there are cases where it is easy to appropriately adjust the addition amount of the (B) component, (C) component, and (D) component while adjusting the pH to 1 or more and 3 or less in order to obtain the all of the present invention. The desired effect. Examples of the pH adjuster include inorganic acids such as phosphoric acid, sulfuric acid, hydrochloric acid, and nitric acid, and salts of these acids, and one or more of these can be used.

2.6. pH The pH value of the chemical mechanical polishing aqueous dispersion of this embodiment is 1 or more and 3 or less, more preferably 1 or more and 2.5 or less. If the pH is in the above range, the het potential of the component (A) can be easily maintained at +1 mV or more and +5 mV or less. As a result, the dispersion stability of the component (A) in the chemical mechanical polishing aqueous dispersion is improved. In addition, when the pH is in the above range, the polishing speed of a substrate including various materials such as wiring materials, insulating film materials, and barrier metal materials is increased.

In addition, the pH of the chemical mechanical polishing aqueous dispersion of this embodiment can be adjusted by appropriately increasing or decreasing the addition amount of (B) component, (C) component, (D) component, pH adjuster, etc., for example.

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.) under the conditions of 25°C and 1 atmosphere.

2.7. Purpose The chemical mechanical polishing aqueous dispersion of this embodiment is suitable for high-speed polishing of substrates including wiring materials, insulating film materials, barrier metal materials, and other materials, and can also suppress wiring materials or barrier metals during the CMP step. Corrosion of materials. Among these materials, the chemical mechanical polishing aqueous dispersion of this embodiment is particularly capable of high-speed polishing of silicon-containing materials such as tungsten as a wiring material, silicon dioxide as an insulating film material, and nitrogen as a barrier metal material. Titanium oxide substrates, and in particular, can inhibit the corrosion of tungsten or titanium nitride. Therefore, the chemical mechanical polishing aqueous dispersion of this embodiment is particularly suitable for polishing a substrate containing one or more selected from the group consisting of tungsten, silicon dioxide, and titanium nitride.

3. Chemical mechanical polishing method The chemical mechanical polishing method of this embodiment includes: using the chemical mechanical polishing aqueous dispersion to perform (chemical mechanical) on a substrate containing at least one selected from the group consisting of tungsten, silicon dioxide, and titanium nitride Grinding steps. According to the chemical mechanical polishing method of this embodiment, by using the chemical mechanical polishing aqueous dispersion, tungsten, silicon dioxide, and titanium nitride can be polished at high speed, and corrosion of tungsten or titanium nitride can be suppressed.

In the chemical mechanical polishing, for example, a polishing device 100 as shown in FIG. 1 can be used. FIG. 1 is a perspective view schematically showing a polishing device 100. The chemical mechanical polishing is performed by supplying the slurry (chemical mechanical polishing aqueous dispersion) 44 from the slurry supply nozzle 42, and while rotating the turntable 48 to which the polishing cloth 46 is attached, A carrier head 52 holding the substrate 50 abuts. Furthermore, FIG. 1 also shows a water supply nozzle 54 and a dresser 56 together.

The grinding load of the carrying head 52 can be selected in the range of 0.7 psi to 70 psi, preferably 1.5 psi to 35 psi. In addition, the rotation speed of the turntable 48 and the carrying 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 aqueous dispersion) 44 supplied from the slurry supply nozzle 42 can be selected in the range of 10 mL/min to 1,000 mL/min, preferably 50 mL/min to 400 mL/min .

Commercially available polishing devices include, for example, models "EPO-112" and "EPO-222" manufactured by Ebara Manufacturing Co., Ltd.; models "LGP-510" and "LGP manufactured by Lapmaster SFT Co., Ltd." -552"; the models "Mirra" and "Reflexion" manufactured by Applied Material; the models "POLI" manufactured by G&P TECHNOLOGY 400L"; the model "Reflexion LK" manufactured by AMAT; the model "FLTec-15" manufactured by FILTEC; the model "ChaMP" manufactured by Tokyo Precision Co., etc.

4. Examples Hereinafter, the present invention will be described with examples, but the present invention is not limited to these examples at all. Furthermore, the "parts" and "%" in this embodiment are quality standards unless otherwise specified.

4.1. Preparation of water dispersion containing colloidal silica abrasive grains (1) Preparation of water dispersion containing colloidal silica A1 Put 100 g of 28% ammonia water, 160 g of ion exchange water, and 1250 g of methanol to a capacity of 2000 In a cm ³ flask, the temperature was raised to 35°C while stirring at 180 rpm. A mixed solution of 160 g of tetramethoxysilane and 40 g of methanol was slowly added dropwise to the solution, thereby obtaining a colloidal silica/alcohol dispersion. Then, the evaporator was repeated several times while adding ion-exchanged water to the dispersion at 80°C while removing the alcohol component, thereby removing the alcohol in the dispersion, and preparing a colloidal dioxide containing 15% solid content. Aqueous dispersion of silicon A1.

(2) Preparation of water dispersion containing colloidal silica A2 While stirring 1000 g of the prepared aqueous dispersion containing colloidal silica A1, the temperature was raised to 60°C while adding 1 g of a sulfhydryl-containing silane coupling agent (trade name "KBE803" manufactured by Shin-Etsu Chemical Co., Ltd.) , And continue to stir for 2 hours. After that, 8 g of 35% hydrogen peroxide water was put in, and the temperature was maintained at 60°C while stirring for 8 hours. After that, it was cooled to room temperature to obtain an aqueous dispersion of sulfo-modified colloidal silica A2. For a sample obtained by taking out a part of the aqueous dispersion and diluting it with ion-exchanged water, the arithmetic average diameter is measured as the average particle diameter using a dynamic light scattering particle size measuring device (Model "LB550" manufactured by Horiba Manufacturing Co., Ltd.) , The result is 68 nm. In addition, using a zeta potential measuring device (model "DT300" manufactured by Dispersion Technology Inc.), the aqueous dispersion was diluted with ion exchange water so that the colloidal silica A2 became 1% by mass , And adjusted to pH2.4, the colloidal silica A2 has a cheek potential of -34 mV. Furthermore, the polypropylene filter (model Planargard PCL0301E6) with a pore size of 0.3 μm manufactured by Entegris was passed through three passes of the colloidal silica A2 after filtration. The potential is -31 mV.

(3) Preparation of water dispersion containing colloidal silica A3 To 1000 g of the prepared water dispersion containing colloidal silica A1 was added 28% ammonia water and adjusted to pH 10.2. A mixture of 19 g of methanol and 1 g of 3-aminopropyltrimethoxysilane was added dropwise to the solution for 10 minutes while keeping the liquid temperature at 30°C, and then refluxed for 2 hours under normal pressure , Thereby obtaining an aqueous dispersion containing colloidal silica A3 modified by amine groups. For a sample obtained by taking out a part of the aqueous dispersion and diluting it with ion-exchanged water, the arithmetic average diameter is measured as the average particle diameter using a dynamic light scattering particle size measuring device (Model "LB550" manufactured by Horiba Manufacturing Co., Ltd.) , The result is 68 nm. In addition, using a zeta potential measuring device (model "DT300" manufactured by Dispersion Technology Inc.), the aqueous dispersion was diluted with ion-exchanged water so that the colloidal silica A3 became 1% by mass , And adjusted to pH 2.4, the cheek potential of colloidal silica A3 is +29 mV. Furthermore, the polypropylene filter (model Planargard PCL0301E6) with a pore size of 0.3 μm manufactured by Entegris has passed three passes of the filtered colloidal silica A3. The potential is +25 mV.

(4) Preparation of water dispersion containing colloidal silica A4 Put 60 g of 28% ammonia water and 1500 g of ion-exchanged water into a 2000 cm ³ flask, and stir at 180 rpm while raising the temperature to 80°C. A mixed solution of 280 g of tetramethoxysilane and 75 g of methanol was slowly added dropwise to the solution, thereby obtaining a colloidal silica/alcohol dispersion. Then, the evaporator was repeated several times while adding ion-exchanged water to the dispersion at 60°C while removing the alcohol component, thereby removing the alcohol in the dispersion, and preparing a colloidal dioxide containing 15% solid content. Water dispersion of silicon A4. A part of this aqueous dispersion was taken out and diluted with ion-exchanged water, and the arithmetic average diameter was measured as the average particle diameter using a dynamic light scattering particle size measuring device (Model "LB550" manufactured by Horiba Manufacturing Co., Ltd.) , The result is 27 nm. In addition, using a zeta potential measuring device (model "DT300" manufactured by Dispersion Technology Inc.), the aqueous dispersion was diluted with ion-exchanged water so that the colloidal silica A4 became 1% by mass , And adjusted to pH2.4, the colloidal silica A4 has a potential of -0.3 mV. Furthermore, the polypropylene filter (model Planargard PCL0301E6) with a pore size of 0.3 μm manufactured by Entegris has passed three passes of the filtered colloidal silica A4. The potential is -1 mV.

(5) Preparation of water dispersion containing colloidal silica A5 Put 6 g of triethanolamine and 1500 g of ion-exchanged water into a flask with a capacity of 2000 cm ³ and stir at 180 rpm while heating to 70°C. 280 g of tetramethoxysilane was slowly added dropwise to the solution, thereby obtaining a colloidal silica/methanol dispersion. Then, an evaporator was used to add ion-exchange water to the dispersion at 60°C while removing the methanol component, thereby removing the methanol in the dispersion, and preparing a colloidal silica A5 containing colloidal silica with a solid content of 15%. Water dispersion. For a sample obtained by taking out a part of the aqueous dispersion and diluting it with ion-exchanged water, the arithmetic average diameter is measured as the average particle diameter using a dynamic light scattering particle size measuring device (Model "LB550" manufactured by Horiba Manufacturing Co., Ltd.) , The result is 15 nm. In addition, using a zeta potential measuring device (model "DT300" manufactured by Dispersion Technology Inc.), the aqueous dispersion was diluted with ion exchange water so that the colloidal silica A5 became 1% by mass , And adjusted to pH2.4, the colloidal silica A5 has a potential of -0.3 mV. Furthermore, the polypropylene filter (model Planargard PCL0301E6) with a pore size of 0.3 μm manufactured by Entegris has passed the filtration of colloidal silica A5 for 3 times. The potential is -1 mV.

(6) Preparation of water dispersion containing colloidal silica A6. Put 120 g of the prepared water dispersion containing colloidal silica A5, 1300 g of ion exchange water, and 10 g of triethanolamine to a capacity of 2000 cm ³ In the flask, the temperature was raised to 70°C while stirring at 180 rpm. 280 g of tetramethoxysilane was slowly added dropwise to the solution, thereby obtaining a colloidal silica/methanol dispersion. Then, an evaporator was used to remove the methanol component while adding ion-exchanged water to the dispersion at 60°C to remove the methanol in the dispersion to prepare a colloidal silica A6 containing colloidal silica with a solid content of 15%. Water dispersion. For a sample obtained by taking out a part of the aqueous dispersion and diluting it with ion-exchanged water, the arithmetic average diameter is measured as the average particle diameter using a dynamic light scattering particle size measuring device (Model "LB550" manufactured by Horiba Manufacturing Co., Ltd.) , The result is 38 nm. In addition, using a zeta potential measuring device (model "DT300" manufactured by Dispersion Technology Inc.), the aqueous dispersion was diluted with ion exchange water so that the colloidal silica A6 became 1% by mass , And adjusted to pH 2.4, the cheek potential of colloidal silica A6 is +2.6 mV. Furthermore, the polypropylene filter (model Planargard PCL0301E6) with a pore size of 0.3 μm manufactured by Entegris has passed the filtration of colloidal silica A6 for 3 times. The potential is +3.5 mV.

(7) Preparation of water dispersion containing colloidal silica A7. Put 120 g of the prepared water dispersion containing colloidal silica A5, 1300 g of ion exchange water, and 10 g of triethanolamine to a capacity of 2000 cm ³ In the flask, the temperature was raised to 70°C while stirring at 180 rpm. 200 g of tetramethoxysilane was slowly added dropwise to the solution, thereby obtaining a colloidal silica/methanol dispersion. Then, an evaporator was used to add ion-exchange water to the dispersion at 60°C while removing the methanol component, thereby removing the methanol in the dispersion, and preparing a colloidal silica A7 containing colloidal silica with a solid content of 15%. Water dispersion. For a sample obtained by taking out a part of the aqueous dispersion and diluting it with ion-exchanged water, the arithmetic average diameter is measured as the average particle diameter using a dynamic light scattering particle size measuring device (Model "LB550" manufactured by Horiba Manufacturing Co., Ltd.) , The result is 33 nm. In addition, using a zeta potential measuring device (model "DT300" manufactured by Dispersion Technology Inc.), the aqueous dispersion was diluted with ion exchange water so that the colloidal silica A7 became 1% by mass , And adjusted to pH2.4, the colloidal silica A7 has a potential of +1.8 mV. Furthermore, the polypropylene filter (model Planargard PCL0301E6) with a pore size of 0.3 μm manufactured by Entegris has passed the filtration of colloidal silica A7 for 3 times. The potential is +3 mV.

(8) Preparation of water dispersion containing colloidal silica A8. Put 120 g of the prepared water dispersion containing colloidal silica A5, 1300 g of ion exchange water, and 10 g of triethanolamine to a capacity of 2000 cm ³ In the flask, the temperature was raised to 70°C while stirring at 180 rpm. 570 g of tetramethoxysilane was slowly added dropwise to the solution, thereby obtaining a colloidal silica/methanol dispersion. Then, an evaporator was used to remove methanol while adding ion-exchanged water to the dispersion at 60°C to remove the methanol in the dispersion to prepare water containing colloidal silica A8 with a solid content of 15%. Dispersions. For a sample obtained by taking out a part of the aqueous dispersion and diluting it with ion-exchanged water, the arithmetic average diameter is measured as the average particle diameter using a dynamic light scattering particle size measuring device (Model "LB550" manufactured by Horiba Manufacturing Co., Ltd.) , The result is 57 nm. In addition, using a zeta potential measuring device (model "DT300" manufactured by Dispersion Technology Inc.), the aqueous dispersion was diluted with ion exchange water so that the colloidal silica A8 became 1% by mass , And prepared to have a potential of +4.6 mV at pH 2.4. Furthermore, the polypropylene filter (model Planargard PCL0301E6) with a pore size of 0.3 μm manufactured by Entegris has passed the filtration of colloidal silica A8 for 3 times. The potential is +3.5 mV.

(9) Preparation of water dispersion containing colloidal silica A9 in a 2000 cm ³ flask, add 28% ammonia to 1000 g of the prepared water dispersion containing colloidal silica A1 and adjust it to pH 10.2. A mixture of 19 g of methanol and 0.5 g of 3-aminopropyltrimethoxysilane was added dropwise to the solution for 10 minutes while keeping the liquid temperature at 30°C, and then refluxed for 2 hours under normal pressure , Thereby obtaining an aqueous dispersion containing amine modified colloidal silica A9. For a sample obtained by taking out a part of the aqueous dispersion and diluting it with ion-exchanged water, the arithmetic average diameter is measured as the average particle diameter using a dynamic light scattering particle size measuring device (Model "LB550" manufactured by Horiba Manufacturing Co., Ltd.) , The result is 65 nm. In addition, using a zeta potential measuring device (model "DT300" manufactured by Dispersion Technology Inc.), the aqueous dispersion was diluted with ion-exchanged water so that the colloidal silica A9 became 1% by mass , And prepared to have a potential of +20 mV at pH 2.4. Furthermore, the polypropylene filter (model Planargard PCL0301E6) with a pore size of 0.3 μm manufactured by Entegris has passed the filtration of colloidal silica A9 for 3 times. The potential is 10 mV.

4.2. Preparation of water-based dispersion for chemical mechanical grinding A predetermined amount of any one of the prepared colloidal silica-containing water dispersion was put into a polyethylene bottle with a capacity of 5 liters, and the amine compound, metal nitrate or metal described in Table 1 or Table 2 Sulfate and chelating agent are added to it so that it may become each content, and fully stirred. After that, nitric acid was added as a pH adjuster, and the pH was adjusted to the value shown in Table 1 or Table 2. After that, filtration was performed with a filter with a pore diameter of 0.3 μm, and the chemical mechanical polishing aqueous dispersions of Examples 1 to 5 and Comparative Examples 1 to 9 were obtained. In addition, immediately before performing various evaluation tests described below, 35 mass% hydrogen peroxide water was added to the prepared chemical mechanical polishing aqueous dispersion so as to be converted into hydrogen peroxide to 2 mass %.

4.3. Evaluation method 4.3.1. Evaluation of grinding speed Using the prepared aqueous dispersion for chemical mechanical polishing, and using tungsten wafers, silicon dioxide wafers, and titanium nitride wafers as objects to be polished, a chemical mechanical polishing test was performed under the following polishing conditions for 1 minute. And evaluate the grinding speed. The evaluation criteria are as follows. The results are shown in Table 1 and Table 2 together.

<Grinding conditions> · Grinding device: Model "ChaMP" manufactured by Tokyo Precision ·Lapping pad: "IC1000" manufactured by Nitta Haas ·Supply rate of water-based dispersion for chemical mechanical polishing: 200 mL/min ·Pressure plate speed: 80 rpm ·Head speed: 70 rpm ·Head pressing pressure: 4 psi Polishing speed (nm/min) = (thickness of each film before polishing-thickness of each film after polishing) / polishing time

Furthermore, the thickness of the silicon dioxide film is measured by the model "Analyzer 1512" manufactured by n&k Technology, and the thickness of the tungsten film and titanium nitride film is measured by a resistivity measuring machine ( The model "ResMap (ResMap)" manufactured by CDE Corporation) was used to measure the resistance by the DC four-point probe method. Based on the sheet resistance value and the volume resistivity of the tungsten film or titanium nitride film, it was calculated by the following formula. Film thickness (nm) = [Volume resistivity of tungsten film or titanium nitride film (Ω·m) ÷ sheet resistance value (Ω)]×10 ⁹

<Evaluation criteria of tungsten film> · When the polishing rate of the tungsten film is 400 nm/min or more, the polishing rate is sufficiently large, so it can be processed at a high speed in actual device wafer polishing and is practical, so it is judged to be particularly good. It is described as "◎" in Table 1 and Table 2. · When the polishing speed of the tungsten film is 300 nm/min or more and less than 400 nm/min, the polishing speed is high. Therefore, high-speed processing can be performed in actual device wafer polishing, which is practical and therefore judged as good , Described as "○" in Table 1 and Table 2. · When the polishing rate is less than 300 nm/min, the polishing rate is low, so it is difficult to be practical, and it is judged to be defective. It is described as "×" in Table 1 and Table 2.

<Evaluation criteria for silicon dioxide film> · When the polishing rate of the silicon dioxide film is 40 nm/min or more, the polishing rate is sufficiently high, so it can be processed at a high speed in actual device wafer polishing and is practical, so it is judged to be particularly good. It is described as "◎" in 1 and Table 2. ·When the polishing speed of the silicon dioxide film is 20 nm/min or more and less than 40 nm/min, the polishing speed is high. Therefore, high-speed processing can be performed in actual device wafer polishing, which is practical, so it is judged As good, it is described as "○" in Table 1 and Table 2. · When the polishing rate of the silicon dioxide film is less than 20 nm/min, the polishing rate is low, so it is difficult to be practical, and it is judged to be defective. It is described as "×" in Table 1 and Table 2.

<Evaluation criteria for titanium nitride film> · When the polishing rate of the titanium nitride film is 300 nm/min or more, the polishing rate is sufficiently large, so that high-speed processing can be performed in actual device wafer polishing, and it is practical, so it is judged to be particularly good. It is described as "◎" in 1 and Table 2. · When the polishing speed of the titanium nitride film is 200 nm/min or more and less than 300 nm/min, the polishing speed is high. Therefore, it is practical to perform high-speed processing in actual device wafer polishing, so it is judged As good, it is described as "○" in Table 1 and Table 2. · When the polishing rate of the titanium nitride film is less than 200 nm/min, the polishing rate is low, so it is difficult to be practical, and it is judged to be defective, and is described as "×" in Table 1 and Table 2.

4.3.2. Evaluation of etching speed A test piece cut into 3 cm×3 cm of the same tungsten wafer used in the evaluation of the polishing rate was used as the object to be processed, and immersed in the chemical mechanical polishing aqueous dispersion at a liquid temperature of 60°C For 5 minutes, measure the etching rate of the tungsten film. The evaluation criteria are as follows. The results are shown in Table 1 and Table 2 together. In addition, the etching rate was measured in the same manner as the above-mentioned polishing rate evaluation. ·Etching speed (nm/min)=((Weight of tungsten wafer before etching-Weight of tungsten wafer after etching)/(Tungsten density×Tungsten substrate area))/etching time

<Evaluation criteria> · When the etching rate is 0 nm/min or more and less than 5 nm/min, the etching rate is particularly small. Therefore, the actual device wafer polishing can easily ensure a balance with the polishing rate, which is practical. It was judged to be particularly good, and was described as "◎" in Table 1 and Table 2. · When the etching rate is 5 nm/min or more and less than 10 nm/min, the etching rate is slightly higher. Therefore, it is necessary to ensure a balance with the polishing rate in actual printed circuit board polishing, but it is practical, so it is judged as It was good, and was described as "○" in Table 1 and Table 2. · When the etching rate is 10 nm/min or more, the etching rate is too high, so it is difficult to be practical, and it is judged to be defective. It is described as "×" in Table 1 and Table 2.

4.3.3. Evaluation of dispersion stability After preparing the chemical mechanical polishing aqueous dispersions of each example and each comparative example, they were allowed to stand at 60°C under normal pressure, and the chemical mechanical polishing aqueous dispersions after standing for 5 days were visually observed to evaluate the dispersion stability. As an evaluation index of dispersion stability, a dynamic light scattering particle size measuring device (Model "LB550" manufactured by Horiba Manufacturing Co., Ltd.) was used, and the arithmetic average diameter was used as the average particle diameter. If the change in the average particle size after standing for 5 days is less than 5 nm, set it as "◎", if it is 5 nm or more and less than 10 nm, it is set as "○", and if it is 10 nm or more or colloidal dioxide has occurred The condition of the aggregation and sedimentation of the silicon abrasive grains is referred to as "×", and the results are shown in Table 1 and Table 2.

4.4. Evaluation results The composition, physical properties, and evaluation results of the chemical mechanical polishing aqueous dispersion used in each example and each comparative example are shown in Table 1 and Table 2 below.

[Table 1]

[Table 2]

In Table 1 above and Table 2 above, the numerical value of each component represents parts by mass. In addition, in each Example and each comparative example, the total amount of each component was 100 parts by mass, and the remainder was ion exchange water.

The components in Table 1 and Table 2 above use the following products or reagents, respectively. ＜Abrasive grains＞ ·A1～A9: the prepared colloidal silica A1～colloid silica A9 ＜Metal Nitrate, Metal Sulfate＞ · Ferric Nitrate: "FN-376" manufactured by Tama Chemical Industry Co., Ltd. ·Iron sulfate: "Iron (II) sulfate heptahydrate" manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. ＜Amine compound＞ ·Sodium laurylamine dipropionate: The trade name "PIONIN C-158D" manufactured by Takemoto Oil ·N-Lauryl-N'-Carboxymethyl-N'-Hydroxyethyl Ethylenediamine Sodium: The trade name "LEBON 101-H" manufactured by Sanyo Chemical Industry Co., Ltd. ＜Chelating agent＞ ·Malonic acid: "Malonic acid" manufactured by Fuso Chemical Industry Co., Ltd. <Oxidant> ·Hydrogen peroxide: "Hydrogen Peroxide Water (30%)" manufactured by Fuji Photo Film Wako Pure Chemical Co., Ltd. ＜pH adjuster＞ Nitric acid: "Nitric acid 1.38" manufactured by Kanto Chemical Co., Ltd.

According to the chemical mechanical polishing aqueous dispersion of Examples 1 to 5, it is known that any one of tungsten films, silicon dioxide films, and titanium nitride films can be polished at high speed, and the etching of the tungsten film can be effectively suppressed . It is inferred from the above results that the chemical mechanical polishing aqueous dispersions of Examples 1 to 5 can achieve good chemical mechanical polishing for substrates with at least one of wiring materials, insulating film materials, and barrier metal materials. .

On the other hand, in the case of using the chemical mechanical polishing aqueous dispersion of Comparative Example 1 to Comparative Example 9, any one of the polishing rate of the tungsten film and the corrosion inhibiting ability of the tungsten film is the same as that of Examples 1 to 5. Compared with the aqueous dispersion of chemical mechanical polishing of the present invention, it becomes a poor result.

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). In addition, the present invention includes configurations obtained by replacing non-essential parts of the configurations described in the embodiments. 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 purpose. In addition, the present invention includes a configuration obtained by adding a known technique to the configuration described in the embodiment.

42: Slurry supply nozzle 44: Slurry (aqueous dispersion for chemical mechanical polishing) 46: Abrasive cloth 48: turntable 50: substrate 52: Carrier head 54: Water supply nozzle 56: Dresser 100: grinding device

Fig. 1 is a perspective view schematically showing a chemical mechanical polishing apparatus.

42: Slurry supply nozzle

44: Slurry (chemical mechanical polishing aqueous dispersion)

46: Abrasive cloth

48: turntable

50: substrate

52: Carrier head

54: Water supply nozzle

56: Dresser

100: grinding device

Claims (10)

A method for manufacturing an aqueous dispersion for chemical mechanical polishing, which contains colloidal silica abrasive grains, an amine compound, and at least one selected from the group consisting of metal nitrates and metal sulfates One, and the manufacturing method of the chemical mechanical polishing aqueous dispersion includes: Step (I), hydrolyze and condense the silane oxide in an aqueous medium with tertiary amine compounds; In step (IV), after the step (I), silane oxide is added dropwise to the aqueous medium to grow colloidal silica abrasive grains with a cheek potential of more than +1 mV and less than +5 mV; as well as Step (V), after the step (IV), add an amine compound and at least one selected from the group consisting of metal nitrates and metal sulfates to the aqueous medium. The method for manufacturing an aqueous dispersion for chemical mechanical polishing as described in item 1 of the scope of patent application further includes: In step (II), after the step (I) and before the step (IV), the aqueous medium is concentrated and the alcohol component is removed. As described in item 1 or item 2 of the scope of patent application, the method for manufacturing an aqueous dispersion for chemical mechanical polishing further includes: Step (III), after the step (I) and before the step (IV), add tertiary amine to the aqueous medium. For example, the method for manufacturing an aqueous dispersion for chemical mechanical polishing according to any one of items 1 to 3 of the scope of patent application further includes: Step (VI), after the step (V), add hydrogen peroxide. The method for producing an aqueous dispersion for chemical mechanical polishing as described in any one of items 1 to 4 of the scope of patent application, wherein the aqueous dispersion for chemical mechanical polishing is used to contain tungsten, silicon dioxide, And more than one substrate in the group consisting of titanium nitride. An aqueous dispersion for chemical mechanical grinding, containing: (A) component, which is colloidal silica abrasive grains with a permanent positive charge of +1 mV or more and +5 mV or less; (B) component, which is selected from at least one of the group consisting of metal nitrate and metal sulfate; (C) component, which is at least one selected from the group consisting of amine compounds and their salts; and (D) component, which is a chelating agent other than the above (C) component, and The pH is 1 or more and 3 or less. The chemical mechanical polishing aqueous dispersion as described in item 6 of the scope of patent application, wherein a tertiary amine compound is contained in the colloidal silica abrasive grains. The chemical mechanical polishing aqueous dispersion as described in item 7 of the scope of patent application, wherein the tertiary amine compound is contained in the colloidal silica abrasive grains. The chemical mechanical polishing aqueous dispersion according to any one of items 6 to 8 of the scope of patent application, which is used to contain one selected from the group consisting of tungsten, silicon dioxide, and titanium nitride The above substrate is polished. A chemical mechanical polishing method includes: Use the chemical mechanical polishing aqueous dispersion as described in any one of the 6th to 9th items of the scope of patent application to contain more than one selected from the group consisting of tungsten, silicon dioxide, and titanium nitride The step of polishing the substrate.

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