TW202020103A - Alumina abrasive grains for chemical mechanical polishing, production method therefor, and chemical mechanical polishing method - Google Patents

Abstract

Provided are alumina abrasive grains for chemical mechanical polishing that: suppress the occurrence of polishing scratches during chemical mechanical polishing when wiring semiconductor devices, while providing high-speed polishing of a surface to be polished; and have excellent dispersion stability in a composition. These alumina abrasive grains for chemical mechanical polishing have: at least part of the surface thereof coated by a silane compound coating; a value for MSi/MAl of 0.01-0.2, when the number of mols of silicon is MSi and the number of mols of aluminum is MAl; and a full width at half maximum value of 0.3-0.5 degree for the peak at which the refractive strength is greatest in an incident angle range of 25-75 degree in a powder X-ray diffraction pattern.

Description

Alumina abrasive grains for chemical mechanical polishing and manufacturing method thereof

The invention relates to an alumina abrasive grain for chemical mechanical polishing and a manufacturing method thereof.

Chemical mechanical polishing (CMP) has rapidly gained popularity in flattening technologies and the like in the manufacture of semiconductor devices. The CMP is to press the object to be polished to the polishing pad, supply the chemical mechanical polishing water-based dispersion to the polishing pad, and slide the object to be polished and the polishing pad against each other, thereby polishing the object to be polished in a chemical and mechanical manner Technology.

In recent years, as semiconductor devices have become more sophisticated, the miniaturization of wiring layers formed in semiconductor devices, including wiring, plugs, and the like, has progressed. Along with this, a method of flattening the wiring layer by chemical mechanical polishing is used. The wiring substrate in the semiconductor device includes an insulating film material, a wiring material, and a barrier metal material for preventing the wiring material from diffusing to the inorganic material film. 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 grind such materials at high speed, alumina abrasive grains with high hardness are sometimes used. Specifically, a polishing composition containing alumina abrasive grains containing α-alumina as a main component, fumed alumina, acid, and water has been proposed (for example, refer to Patent Document 1). [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2004-331886

[Problems to be solved by the invention] However, the polishing composition described in Patent Literature 1 can polish the surface to be polished at high speed by using alumina abrasive grains or the like having high hardness, but there is a problem that the surface to be polished is prone to scratches such as scratches. Such abrasive damage is the main reason for lowering the yield.

In addition, the polishing composition described in Patent Document 1 also has a problem that the alumina abrasive particles settle in a short time and the dispersion stability is low. When the alumina abrasive grains settle, the alumina abrasive grains aggregate with each other. If the polishing composition containing the aggregated alumina abrasive grains is subjected to chemical mechanical polishing, polishing damage such as scratches may occur on the surface to be polished.

Therefore, some aspects of the present invention provide alumina abrasive grains for chemical mechanical polishing that suppresses the occurrence of polishing damage while polishing the surface to be polished at a high speed during the chemical mechanical polishing performed during the formation of the wiring of the semiconductor device In addition, the dispersion stability in the composition is also excellent. [Means to solve the problem]

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

An aspect of the alumina abrasive grains for chemical mechanical polishing of the present invention is alumina abrasive grains where at least a part of the surface is coated with a coating of a silane compound, and the mole number of silicon in the alumina abrasive grains is set to M _Si , when the mole number of aluminum is M _Al , the value of M _Si /M _Al is 0.01 or more and 0.2 or less, and the powder X-ray diffraction pattern is within a range of an incident angle of 25° or more and 75° or less The half-value width of the peak portion where the diffraction intensity becomes maximum is 0.3° or more and 0.5° or less.

In the aspect of the alumina abrasive grain for chemical mechanical polishing, The average primary particle size may be above 30 nm and below 300 nm.

In any aspect of the alumina abrasive grain for chemical mechanical polishing, The film thickness of the silane compound coating may be 1 nm or more and 10 nm or less.

In any aspect of the alumina abrasive grain for chemical mechanical polishing, It can be used to grind substrates containing tungsten.

In any aspect of the alumina abrasive grain for chemical mechanical polishing, The substrate may further contain one or more selected from silicon nitride, silicon dioxide, amorphous silicon, copper, cobalt, titanium, ruthenium, titanium nitride, and tantalum nitride.

An aspect of the method for manufacturing alumina abrasive grains for chemical mechanical polishing of the present invention includes: The half-value width of the peak portion where the average primary particle diameter is 10 nm or more and 1000 nm or less, and the powder X-ray diffraction pattern has the maximum diffraction intensity in the range of the incident angle of 25° or more and 75° or less is Step (a) of preparing α-alumina particle aqueous dispersion liquid having a solid content concentration of 1% by mass or more and 30% by mass or less in which α-alumina particles of 0.3° or more and 0.5° or less are dispersed in water; The step (b) of adding an alkoxysilane compound of 1 part by mass or more and 50 parts by mass or less when the total amount of the α-alumina particles is 100 parts by mass to the aqueous dispersion of α-alumina particles (b) );and The step (c) of growing the silane compound film on the surface of the α-alumina particles.

In one aspect of the method for manufacturing alumina abrasive grains for chemical mechanical polishing, The step (c) can be performed at a temperature below 90°C.

In any aspect of the method for manufacturing alumina abrasive grains for chemical mechanical polishing, It may further include adding ammonia in the step (a). [Effect of invention]

According to the aluminum oxide abrasive grains for chemical mechanical polishing of the present invention, in the chemical mechanical polishing performed when the wiring of the semiconductor device is formed, it is possible to suppress the occurrence of polishing damage while polishing the surface to be polished at high speed. In addition, the alumina abrasive grains for chemical mechanical polishing according to the present invention are also excellent in dispersion stability in the chemical mechanical polishing aqueous dispersion. Therefore, it is more difficult for the surface to be polished to cause scratches such as scratches.

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 the scope of not changing the gist of the present invention.

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

The "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 "barrier metal material" refers to a material such as tantalum nitride, titanium nitride, etc., which is laminated with wiring materials for the purpose of improving the reliability of wiring.

1. Alumina abrasive grains for chemical mechanical polishing At least a part of the surface of the alumina abrasive grains for chemical mechanical polishing of the present embodiment is coated with a coating of a silane compound, and the mole number of silicon is M _Si and the mole of aluminum When the number of ears is set to M _Al , the value of M _Si /M _Al is 0.01 or more and 0.2 or less, and the diffraction intensity of the powder X-ray diffraction pattern is maximized within the range of the incident angle of 25° or more and 75° or less The half-value width of the peak part of is 0.3° or more and 0.5° or less. Hereinafter, the alumina abrasive grains for chemical mechanical polishing of the present embodiment will be described with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing alumina abrasive grains for chemical mechanical polishing according to this embodiment. As shown in FIG. 1, the aluminum oxide abrasive grains 100 for chemical mechanical polishing of the present embodiment (hereinafter, also referred to as “alumina abrasive grains 100 ”) are coated with a silane compound coating 20 on at least a part of the surface of the alumina particles 10. Made. In this manner, the alumina abrasive grain 100 for chemical mechanical polishing of the present embodiment has a core-shell shape with the alumina particles 10 as the core and the silane compound coating 20 as the shell. The surface of the alumina abrasive grains 100 may be covered with the silane compound film 20 on the entire surface or only a part of it, but it is preferable to cover the entire surface. At least a part of the surface of the alumina particles 10 is coated with the coating 20 of the silane compound, whereby the hardness of the surface of the alumina abrasive grains 100 is moderately relaxed. Therefore, while increasing the polishing speed of the polished surface, it is difficult for the polished surface Abrasion damage such as scratches. In addition, in the chemical mechanical polishing water-based dispersion, it is difficult to cause aggregation of alumina abrasive grains, and the dispersion stability of the alumina abrasive grains is improved.

The film thickness of the coating film 20 is preferably 1 nm or more and 10 nm or less. If the film thickness of the coating film 20 is within the above range, the polishing rate does not decrease, the occurrence of polishing damage on the surface to be polished can be suppressed, and the dispersion stability can be easily improved in the chemical mechanical polishing aqueous dispersion. Here, when the film thickness of the film 20 is 1 nm or more and 3 nm or more, it is particularly easy to suppress the reduction in the polishing speed of the surface to be polished, and when the film thickness of the film 20 is 6 nm or more and 10 nm or less In particular, it is easy to suppress the occurrence of polishing damage on the polished surface. In addition, the film thickness of the coating can be obtained as the average value of the values obtained by measuring the maximum value of the film thickness of the alumina abrasive grains 100 of 100 samples using a transmission electron microscope (TEM).

Regarding the alumina abrasive grains 100, in the powder X-ray diffraction pattern, the half-value width of the peak portion where the diffraction intensity becomes maximum within the range of the incident angle of 25° or more and 75° or less is 0.3° or more and 0.5° or less. The half-value width is preferably 0.3° or more and 0.4° or less, and more preferably 0.32° or more and 0.38° or less. In general, the powder X-ray diffraction pattern of crystalline alumina abrasive grains has a peak of alumina whose diffraction intensity becomes maximum within a range of an incident angle of 25° or more and 75° or less. Here, regarding the microcrystalline homogeneous alumina abrasive grains, the peak at which the diffraction intensity becomes maximum within the above range becomes sharp, and as a result, the half-value width of the peak portion tends to take a value less than 0.3°. However, the microcrystalline homogeneous alumina abrasive grains whose value is less than 0.3° tend to cause abrasive damage to the surface to be polished. On the other hand, the crystallites having a value exceeding 0.5° have poor homogeneity of the alumina crystal grains, and the polishing characteristics tend to decrease, and the polishing speed of the surface to be polished tends to decrease. Therefore, if the alumina abrasive grains 100 having the above-mentioned value are in the above-mentioned range, it is possible to suppress the occurrence of polishing damage while polishing the surface to be polished at high speed.

Production of alumina abrasive grains as the half-value width of the peak portion where the diffraction intensity at the incident angle is 25° or more and 75° or less in the powder X-ray diffraction pattern is 0.3° or more and 0.5° or less The method includes a method for producing sub-micron-sized α-alumina using a sol-gel process, for example, Japanese Patent Publication No. 10-510238, and Japanese Patent Publication No. Hei 10- The manufacturing method described in Japanese Patent No. 506669 and Japanese Patent Laid-Open No. 10-504348.

About 100 alumina abrasive grains, when the number of moles of silicon in the set M _Si, the number of moles of aluminum to M _Al, is 0.01 or more and 0.2 or less M _Si / M _Al, preferably 0.01 or more It is 0.15 or less, more preferably 0.02 or more and 0.1 or less, and particularly preferably 0.03 or more and 0.1 or less. If the value of the molar ratio of silicon to aluminum (M _Si /M _Al ) contained in the alumina abrasive grains 100 is within the above range, it can be presumed that a homogeneous and moderate film thickness is formed on the surface of the alumina particles 10 The coating film 20 of the silane compound does not reduce the polishing speed of the surface to be polished, and can suppress the occurrence of polishing damage. Furthermore, the dispersion stability of the alumina abrasive particles 100 is easily improved in the chemical mechanical polishing water-based dispersion.

2. Manufacturing method of alumina abrasive grains for chemical mechanical polishing The method for producing alumina abrasive grains for chemical mechanical polishing of this embodiment includes: making the average primary particle diameter 10 nm or more and 1000 nm or less, and the powder X-ray diffraction pattern at an incident angle of 25° or more and 75° or less Α-alumina particles with a half-value width of the peak portion where the diffraction intensity becomes the largest within the range of 0.3% or more and 0.5° or less are dispersed in water, and a solid content concentration of 1% by mass or more and 30% by mass or less is prepared Step (a) of the aqueous dispersion of α-alumina particles; when the total amount of the α-alumina particles is added to the aqueous dispersion of α-alumina particles as 100 parts by mass, it is 1 part by mass or more and Step (b) of an alkoxysilane compound of 50 parts by mass or less; and step (c) of growing a coating of the silane compound on the surface of the α-alumina particles. According to the method for producing alumina abrasive grains for chemical mechanical polishing of the present embodiment, a uniform silane compound coating with an appropriate film thickness can be formed on the surface of alumina particles. Therefore, the polishing rate does not decrease, and the occurrence of polishing damage on the surface to be polished can be suppressed, and the dispersion stability can be easily improved in the chemical mechanical polishing aqueous dispersion. Hereinafter, each step of the method for producing alumina abrasive grains for chemical mechanical polishing of the present embodiment will be described.

2.1. Step (a) Step (a) is to maximize the peak value of the diffraction intensity in the range of the incident angle of 25° or more and 75° or less in the powder X-ray diffraction pattern with an average primary particle diameter of 10 nm or more and 1000 nm or less The step of preparing α-alumina particles aqueous dispersion having a solid content concentration of 1% by mass or more and 30% by mass or less in which α-alumina particles having a half-value width of 0.3° or more and 0.5° or less are dispersed in water.

The average primary particle size of the α-alumina particles used in step (a) is 10 nm or more and 1000 nm or less, but the larger the average primary particle size, the smaller the surface area per unit weight, and the more difficult it is to form a coating, which is preferable It is 30 nm or more and 300 nm or less, more preferably 85 nm or more and 200 nm or less. If the average primary particle size is in the range of 30 nm or more and 300 nm or less, it is easy to prepare the alumina polishing particles for chemical mechanical polishing with a value of M _Si /M _Al of 0.01 or more and 0.2 or less, also in terms of dispersion stability favorable. The average primary particle size of α-alumina particles can be measured using a transmission electron microscope (TEM), for example, as the average particle size of 100 particles. Examples of the transmission electron microscope include a device model "HITACHI H-7650" manufactured by Hitachi High-Technologies, and a device model "JEM2100Plus" manufactured by JEOL.

In addition, regarding the α-alumina particles used in step (a), the half-value width of the peak portion where the diffraction intensity becomes the largest in the range of the incident angle of 25° or more and 75° or less in the powder X-ray diffraction pattern It is 0.3° or more and 0.5° or less. The half-value width is preferably 0.3° or more and 0.4° or less, and more preferably 0.32° or more and 0.38° or less. The crystallite-homogeneous α-alumina particles whose value is less than 0.3° tend to cause abrasive damage to the surface to be polished. On the other hand, the α-alumina particles with poor homogeneity of the crystallites whose values are above 0.5° tend to have poor polishing properties, and the polishing rate of the surface to be polished tends to decrease. Therefore, if the α-alumina particles have the above-mentioned value, it is possible to suppress the occurrence of polishing damage while polishing the surface to be polished at high speed.

Examples of such a method for producing α-alumina particles include a method for producing sub-micron-sized α-alumina particles using a sol-gel process. For example, Japanese Patent Publication No. 10-510238, Japanese Patent The manufacturing method described in Japanese Patent Publication No. 10-506669 and Japanese Patent Publication No. 10-504348.

The method for dispersing the α-alumina particles in water is not particularly limited, as long as the water is weighed into the container, and the α-alumina particles are slowly poured into the container, and the whole is made uniform by a stirring member such as a magnetic stirrer That's it. When agglomerates of α-alumina particles remain, dispersers such as high-speed shear mixers, homogenizers, planetary mixers, and kneaders can also be used.

The solid content concentration of the aqueous dispersion of α-alumina particles is 1% by mass or more and 30% by mass or less, but preferably 1% by mass or more and 20% by mass or less. When the solid content concentration of the aqueous dispersion of α-alumina particles is within the above range, it is easy to prepare alumina abrasive particles for chemical mechanical polishing having a value of M _Si /M _Al of 0.01 or more and 0.2 or less. In addition, it is possible to form a homogeneous coating while suppressing the aggregation of alumina abrasive grains.

It is preferable to add ammonia water as a catalyst to the aqueous dispersion of α-alumina particles. The amount of ammonia added is not particularly limited, and can be adjusted so that the pH of the aqueous dispersion of α-alumina particles becomes 8-12. In such a pH range, ammonia functions as a catalyst, and the alkoxy group of the alkoxysilane compound is hydrolyzed into hydroxyl groups by the water present in the surrounding environment, which is adsorbed, hydrogen bonded, or dehydrated. It is bonded to the surface of α-alumina particles. In this way, the surface of the α-alumina particles is covered with the coating of the silane compound. That is, the term "coated with a silane compound film" means that the hydroxyl group derived from the alkoxysilane compound is bonded to the surface of the alumina particles by adsorption, hydrogen bonding, or dehydration bonding.

2.2. Step (b) The step (b) is to add an alkoxysilane having a total amount of the α-alumina particles of 100 parts by mass or more to 50 parts by mass or less to the aqueous dispersion of α-alumina particles. Compound steps.

The alkoxysilane compound used in step (b) is preferably a trialkoxysilane. Specific examples of trialkoxysilanes include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, and n-propyltrimethoxysilane. Silane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-pentyltrimethoxysilane Silane, n-hexyltrimethoxysilane, n-heptyltrimethoxysilane, n-octyltrimethoxysilane, 2-ethylhexyltrimethoxysilane, n-decyltrimethoxysilane, n-dodecyltrimethyl Oxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, cyclohexyltrimethoxysilane, cyclohexyltriethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3 -Chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriethoxysilane , 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-(2 -Aminoethyl)-3-aminopropyltriethoxysilane, 2-hydroxyethyltrimethoxysilane, 2-hydroxyethyltriethoxysilane, 2-hydroxypropyltrimethoxysilane, 2-hydroxypropyltriethoxysilane, 3-hydroxypropyltrimethoxysilane, 3-hydroxypropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxy Silane, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl Triethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(methyl Group) propenyl propyl propyl trimethoxy silane, 3- (meth) propyl propyl propyl triethoxy silane, 3-urea propyl trimethoxy silane, 3-urea propyl triethoxy Silane, methyltriethoxysilane, etc. Among these, 3-aminopropyltriethoxysilane and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane are preferred. It is easier to form alumina abrasive grains that are formed from a coating derived from 3-aminopropyltriethoxysilane or N-2-(aminoethyl)-3-aminopropyltrimethoxysilane It is preferable to suppress the occurrence of grinding damage, and further to improve the dispersion stability in the aqueous dispersion of chemical mechanical polishing.

When the total amount of the α-alumina particles is 100 parts by mass, the addition amount of the alkoxysilane compound in step (b) is 1 part by mass or more and 50 parts by mass or less, preferably 10 parts by mass or more And below 35 parts by mass. If the amount of the alkoxysilane compound added is within the above range, the aggregation of α-alumina particles is suppressed, and the oxidation of the chemical mechanical polishing for the M _Si /M _Al value is 0.01 or more and 0.2 or less. Aluminum abrasive grains.

2.3. Step (c) Step (c) is a step of growing a coating of the silane compound derived from the alkoxysilane compound on the surface of the α-alumina particles. Specifically, after step (b), the aqueous dispersion of α-alumina particles to which the alkoxysilane compound is added is stirred at a temperature of 90° C. or lower for 1 to 10 hours, whereby the coating of the silane compound can be obtained It grows on the surface of α-alumina particles.

The upper limit of the temperature of the aqueous dispersion of α-alumina particles during stirring is preferably 90°C, more preferably 70°C, still more preferably 60°C, still more preferably 50°C, and particularly preferably 45°C. On the other hand, the lower limit of the temperature of the aqueous dispersion of α-alumina particles during stirring is preferably 20°C, more preferably 25°C, still more preferably 30°C, and particularly preferably 35°C. By growing the coating of the silane compound at a temperature in the above range, the added ammonia as a catalyst is not scattered, and a coating with moderate strength can be formed on the surface of the α-alumina particles. In addition, while suppressing the aggregation of alumina abrasive grains, alumina abrasive grains for chemical mechanical polishing having a film of a silane compound having a sufficient film thickness can be prepared.

In this way, the coating of the silane compound can be grown on the surface of the α-alumina particles, but it is preferable to finally cool to room temperature and add an acid to adjust the pH to 1 to 6. By setting such a pH range, there is a case where the surface to be polished interacts with alumina abrasive grains for chemical mechanical polishing, and the polishing speed of the surface to be polished can be further increased.

3. Use The aluminum oxide abrasive grains for chemical mechanical polishing of this embodiment have a moderate hardness by forming a coating of a silane compound on the surface as described above, and therefore can be used at high speeds during chemical mechanical polishing performed when forming wiring of a semiconductor device Ground grinding of the surface to be polished suppresses the occurrence of polishing damage.

In addition, when the alumina abrasive grains for chemical mechanical polishing of the present embodiment are used in an acidic region having a pH of 1 to 6, the interaction between the surface to be polished and the alumina abrasive grains for chemical mechanical polishing can be caused, whereby further Increase the polishing speed of the surface to be polished. The aluminum oxide abrasive grains for chemical mechanical polishing of this embodiment are particularly suitable for containing silicon nitride, silicon dioxide, amorphous silicon, tungsten, copper, cobalt, titanium, ruthenium, silicon nitride, titanium nitride, and nitrogen. Abrasive materials that are subjected to chemical mechanical polishing of the surface to be polished, such as tantalum, are particularly suitable as abrasive materials for chemical mechanical polishing of the surface to be polished containing tungsten.

The chemical mechanical polishing water-based dispersion used in chemical mechanical polishing may contain an oxidizing agent such as iron nitrate or hydrogen peroxide, amine-substituted silane, and interface activity in addition to the aluminum oxide abrasive particles for chemical mechanical polishing and water as the main liquid medium. Agents, nitrogen-containing heterocyclic compounds, water-soluble polymers, pH adjusters, etc.

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

4.1. Preparation of alumina abrasive grains for chemical mechanical grinding <Example 1> Add water to the product name "7992 Alumina Dispersion" of Saint-Gobain Ceramic Materials, Inc. to prepare a dispersion of 27.47 g/L in alumina conversion. 500 mL of this dispersion liquid was put in a flask, and while stirring with a stirrer, 5 wt% ammonia water was added until the pH became 10.3. After stirring the dispersion at room temperature for 30 minutes, 1.77 g of 3-amino propyl triethoxy silane (APTES) was added (the molar ratio of silicon to aluminum is 0.06). Then, the temperature was raised to 40°C and stirred at 40°C for 5 hours. Then, it cooled to room temperature, and 70% nitric acid was added until pH became 3.0. In this way, a dispersion of alumina abrasive grains coated with a silane compound coating was obtained. In addition, the half-value width of X-ray fluorescence (XRF) indicates the value measured using the alumina particles before coating. For other evaluations, the obtained silane compound-coated alumina abrasive particle dispersion was used according to the following method. The results are shown in Table 1 below.

<Example 2> Add water to the product name "7992 Alumina Dispersion" of Saint-Gobain Ceramic Materials, Inc. to prepare a dispersion of 27.47 g/L in alumina conversion. 500 mL of this dispersion liquid was put in a flask, and while stirring with a stirrer, 5 wt% ammonia water was added until the pH became 10.3. After the dispersion was stirred at room temperature for 30 minutes, 2.66 g of 3-aminopropyltriethoxysilane (APTES) was added (the molar ratio of silicon to aluminum was 0.09). Then, the temperature was raised to 40°C and stirred at 40°C for 5 hours. Then, it cooled to room temperature, and 70% nitric acid was added until pH became 3.0. In this way, a dispersion of alumina abrasive grains coated with a silane compound coating was obtained. Various evaluations were performed in the same manner as in Example 1. The results are shown in Table 1 below.

<Example 3> Add water to the product name "7992 Alumina Dispersion" of Saint-Gobain Ceramic Materials, Inc. to prepare a dispersion of 27.47 g/L in alumina conversion. 500 mL of this dispersion liquid was put in a flask, and while stirring with a stirrer, 5 wt% ammonia water was added until the pH became 10.3. After stirring the dispersion at room temperature for 30 minutes, 0.89 g of 3-aminopropyltriethoxysilane (APTES) was added (the molar ratio of silicon to aluminum was 0.03). Then, the temperature was raised to 40°C and stirred at 40°C for 5 hours. Then, it cooled to room temperature, and 70% nitric acid was added until pH became 3.0. In this way, a dispersion of alumina abrasive grains coated with a silane compound coating was obtained. Various evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1 below.

<Example 4> Add water to the product name "7992 Alumina Dispersion" of Saint-Gobain Ceramic Materials, Inc. to prepare a dispersion of 27.47 g/L in alumina conversion. 500 mL of this dispersion liquid was put in a flask, and while stirring with a stirrer, 5 wt% ammonia water was added until the pH became 10.3. After stirring the dispersion at room temperature for 30 minutes, N-2-(aminoethyl)-3-aminopropyl trimethoxysilane (N-2-(aminoethyl)-3-aminopropyl trimethoxy silane, AAPTMS) 1.78 g (the molar ratio of silicon to aluminum is 0.06). Then, the temperature was raised to 40°C and stirred at 40°C for 5 hours. Then, it cooled to room temperature, and 70% nitric acid was added until pH became 3.0. In this way, a dispersion of alumina abrasive grains coated with a silane compound coating was obtained. Various evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1 below.

<Example 5> Water was added to Saint-Gobain Ceramic Materials (Inc.) product name "GEN 4-H" alumina dispersion to prepare a dispersion of 27.47 g/L in alumina conversion. 500 mL of this dispersion liquid was put in a flask, and while stirring with a stirrer, 5 wt% ammonia water was added until the pH became 10.3. After the dispersion was stirred at room temperature for 30 minutes, 2.66 g of 3-aminopropyltriethoxysilane (APTES) was added (the molar ratio of silicon to aluminum was 0.09). Then, the temperature was raised to 40°C and stirred at 40°C for 5 hours. Then, it cooled to room temperature, and 70% nitric acid was added until pH became 3.0. In this way, a dispersion of alumina abrasive grains coated with a silane compound coating was obtained. Various evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1 below.

<Example 6> In the same manner as in Example 1, an alumina abrasive particle dispersion liquid coated with a silane compound coating was obtained.

<Example 7> In the same manner as in Example 1, an alumina abrasive particle dispersion liquid coated with a silane compound coating was obtained.

<Comparative Example 1> Saint-Gobain Ceramic Materials (Inc.) product name "7992 alumina dispersion" is not coated, but used directly and evaluated. The various evaluation results are shown in Table 1 below.

<Comparative example 2> Add water to the product name "7992 Alumina Dispersion" of Saint-Gobain Ceramic Materials, Inc. to prepare a dispersion of 27.47 g/L in alumina conversion. 500 mL of this dispersion liquid was put in a flask, and while stirring with a stirrer, 5 wt% ammonia water was added until the pH became 10.3. After the dispersion was stirred at room temperature for 30 minutes, 0.18 g of 3-aminopropyltriethoxysilane (APTES) was added (the molar ratio of silicon to aluminum is 0.006). Then, the temperature was raised to 40°C and stirred at 40°C for 5 hours. Then, it cooled to room temperature, and 70% nitric acid was added until pH became 3.0. In this way, a dispersion of alumina abrasive grains coated with a silane compound coating was obtained. In this case, since the coating of the silane compound is too thin, the film thickness cannot be measured by TEM. Various evaluations were carried out in the same manner as in Example 1. The results are shown in Table 1 below.

<Comparative Example 3> Saint-Gobain Ceramic Materials (Inc.) product name "GEN 4-H" alumina dispersion liquid is not coated, but directly used and evaluated. The various evaluation results are shown in Table 1 below.

<Comparative Example 4> Water was added to the alumina particles "AA-04" manufactured by Sumitomo Chemical to prepare a dispersion of 27.47 g/L in terms of alumina. 500 mL of this dispersion liquid was put in a flask, and while stirring with a stirrer, 5 wt% ammonia water was added until the pH became 10.3. After the dispersion was stirred at room temperature for 30 minutes, 0.6 g of 3-aminopropyltriethoxysilane (APTES) (molar ratio of silicon to aluminum of 0.02) was added. Then, the temperature was raised to 40°C and stirred at 40°C for 5 hours. Then, it cooled to room temperature, and 70% nitric acid was added until pH became 3.0. In this way, a dispersion of alumina abrasive grains coated with a silane compound coating was obtained. As in Example 1, the film thickness of the coating was 5 nm. Various evaluations were carried out in the same manner as in Example 1, and the results are shown in Table 1 below.

4.2. Physical properties evaluation of alumina abrasive grains <Measurement of average primary particle size and film thickness> For the obtained alumina abrasive grains, a transmission electron microscope (TEM) (Hitachi High-Technologies) device model "Hitachi H-7650" was used to measure 100 particles at a time. For the particle size, calculate the average primary particle size. The film thickness of the coating formed on the surface of the alumina abrasive grains is the average value of the values obtained by measuring the maximum value of the film thickness of the alumina abrasive grains obtained by measuring 100 samples using a TEM scale gauge. Find out. The results are shown in Table 1 below.

<Measurement of X-ray diffraction intensity> The half-value width of the peak portion where the diffraction intensity in the powder X-ray diffraction pattern of the alumina abrasive grains becomes the largest was measured under the following conditions. ·Device: Fully automatic horizontal multi-purpose X-ray diffraction device SmartLab (manufactured by Rigaku) ·X-ray source: CuKα 3kw (water cooled) ·Measurement method: Powder method using glass sample plate ·Slit: Prebake (Prebake, PB) resolution capability ·Measurement range: 15 degrees (degree)-120 degrees ·Step (step): 0.05 degrees ·Scanning speed: 0.5 degree/minute (continuous)

<Measurement of M _Si /M _Al > The molar ratio of aluminum and silicon of the obtained alumina abrasive grains was measured by the following method. After the obtained alumina abrasive particle dispersion is sufficiently dried to obtain alumina abrasive particle powder, 10 g of tetraethoxysilane and 0.1 g of potassium hydroxide are added to 0.1 g of the dried powder and heated Reflux for 1 hour. After distilling off the liquid components obtained in the above steps under a reduced pressure of 1 hPa, a gas chromatograph (device: 7890 manufactured by Agilent Technologies), column: BPX-5 30 m×250 μm×0.25 μm) quantify 3-aminopropyltriethoxysilane and calculate the molar number, thereby calculating the molar number of silicon. On the other hand, the residue after the heating and refluxing step is washed with an aqueous solution of potassium hydroxide, so that the silicon component is completely dissolved and removed, and then washed with pure water. The separation of the cleaning solution and the particles is performed by using a centrifugal separator (CP65β manufactured by Hitachi Koki) under the conditions of 25° C. and 4000 rpm for 1 hour. The molar number of aluminum atoms was calculated from the weight of the particles after washing. The molar ratio was calculated based on the obtained molar numbers of aluminum and silicon.

4.3. Preparation of water-based dispersions for chemical mechanical grinding Any one of the prepared alumina abrasive particle dispersions was put into a polyethylene bottle having a capacity of 1 liter so as to be the amount of abrasive particles described in Table 1 below, and Table 1 below was added thereto The described compound was added with water so as to be 100 parts by mass in total and stirred well. Thereafter, if necessary, a pH adjuster is added to adjust the pH to the value shown in Table 1 below. After that, it was filtered with a filter having a pore diameter of 0.3 μm to obtain water-based dispersions for each chemical mechanical polishing.

4.4. Physical properties evaluation of water dispersion of chemical mechanical polishing <Measurement of average secondary particle size> Using dynamic light scattering (DLS) (a dynamic light scattering particle size distribution measuring device manufactured by HORIBA, model "LB550"), the alumina contained in the obtained chemical mechanical polishing aqueous dispersion was measured The average secondary particle size of the abrasive particles. The results are shown in Table 1 below.

＜Measurement of Zeta potential＞ Ultrasonic method particle size distribution and other potential measuring device (dispersion technology (Dispersion Technology), model "DT-1200") was used to measure the alumina abrasive particles contained in the obtained chemical mechanical polishing aqueous dispersion Surface charge (other potential). The results are shown in Table 1 below.

<Evaluation of dispersion stability> 20 mL of the obtained aqueous dispersion of chemical mechanical milling was collected into a styrene rod bottle and allowed to stand at 25°C under 1 atmosphere. The time until the transparent layer formed by sedimentation of the particles and the absence of particles no longer existed in the upper layer portion of the chemical mechanical polishing aqueous dispersion in which the particles were dispersed and appeared white was evaluated as the dispersion stability.

<Evaluation of polishing speed> Using the obtained chemical mechanical polishing aqueous dispersion, and using a chemical mechanical polishing device "Poli-400L"(G&P Technology) under the following conditions to oxidize the belt Silicon film substrate (square silicon substrate with silicon oxide film 1500 nm and 4 cm side length), substrate with silicon nitride film (silicon nitride film 200 nm square silicon substrate with 4 cm side length), with tungsten film The substrate (a square silicon substrate with a tungsten film of 350 nm and a side length of 4 cm) was subjected to chemical mechanical polishing. (Polishing conditions) ·Grinding pad: Nitta Haas Co., Ltd., model "IC1000 XY-P" ·Carrier head load: 129 g/cm ² ·Rotating platen speed: 100 rpm · Rotation speed of polishing head: 90 rpm · Supply amount of water-based dispersion for chemical mechanical polishing: 100 mL/min. Furthermore, the polishing speed of the silicon oxide film, silicon nitride film, and tungsten film was calculated using the following calculation formula. ·Grinding speed (Å/minute) = grinding amount (Å)/grinding time (minutes)

<Defect evaluation> Each component was added to a polyethylene container so as to have the composition shown in Table 2 below, and adjusted with pure water so that the total amount of all components became 100 parts by mass. Next, while confirming with a pH meter, while adjusting with stirring with a 5% by mass nitric acid aqueous solution so as to become the pH shown in Table 2 below, each composition for defect evaluation was prepared.

Using the obtained composition for defect evaluation, and using a chemical mechanical polishing device "Poli-400L"(G&P Technology) under the following conditions, a substrate with a silicon oxide film (with silicon oxide) 1500 nm square silicon substrate with a side length of 4 cm) was subjected to chemical mechanical polishing. ·Grinding pad: Nitta Haas Co., Ltd., model "IC1000 XY-P" ·Loading head load: 129 g/cm ² ·Rotating plate speed: 100 rpm ·Grinding head speed: 90 rpm ·Defect Supply volume of evaluation composition: 100 mL/min

Using the above-mentioned composition, a defect inspection device (Eclipse L200N manufactured by Nikon) was used to measure a defect area having a size of 10 μm or more on the polished silicon oxide film substrate. The ratio of the measured defect area to the total substrate area (hereinafter, also referred to as "defect area ratio") is calculated. The defect area ratio of the silicon oxide film substrate polished using the product name "7992 Alumina Dispersion Liquid" of Saint-Gobain Ceramic Materials (Inc.) shown in Comparative Example 1 was used as a reference (defect area ratio = 100% ), and the defect rate is obtained by the following formula. When the defect rate is 70% or less, it can be judged as good. ·Defect rate (%)=(Defect area rate (%)/7992 Defect area rate of alumina dispersion (%))×100

4.5. Evaluation results The physical properties of the alumina abrasive grains for each chemical mechanical polishing, the composition, physical properties of each chemical mechanical polishing composition, and the evaluation results are shown in Table 1 to Table 2 below.

[Table 1]

[Table 2]

In the above Table 1 to Table 2, the numerical values of each component represent parts by mass. In each example and each comparative example, the total amount of each component in the chemical mechanical polishing aqueous dispersion in the table is 100 parts by mass. The abbreviations of the alkoxysilane compounds described in Table 1 to Table 2 are as follows.

<Alkoxysilane compound> ·APTES: manufactured by Tokyo Chemical Industry Co., Ltd., 3-aminopropyltriethoxysilane ·AAPTMS: manufactured by Tokyo Chemical Industry Co., Ltd., N-2-(aminoethyl)-3-aminopropyltrimethoxysilane

It is known that the alumina abrasive grains for chemical mechanical polishing according to the invention of Examples 1 to 7 of the present application are excellent in stability when they are made into an aqueous dispersion. In addition, according to the chemical mechanical polishing aqueous dispersions containing the alumina abrasive grains for chemical mechanical polishing of the invention of Examples 1 to 7, it is known that a tungsten film as a wiring material can be polished at a high speed. Furthermore, according to the composition for defect evaluation containing the alumina abrasive grain for chemical mechanical polishing of the invention of Examples 1 to 7, it is known that the defect rate can be reduced.

Comparative Example 1 is an example of a chemical-mechanical polishing water-based dispersion using alumina abrasive grains not coated with a silane compound as abrasive grains. In the defect evaluation in this case, the defect rate of the substrate after polishing due to the use of alumina abrasive grains not coated with the coating of the silane compound is large.

Comparative Example 2 is an example of reducing the amount of monomers during synthesis to the amount used in normal particle surface treatment. No polymer coating layer was observed on the surface of the alumina abrasive grains. In the defect evaluation, by using alumina abrasive grains in which the coating of the silane compound is not sufficiently formed, the defect area ratio of the substrate after polishing is close to that of uncoated alumina (Comparative Example 1), which is the same as that of Examples 1 to 7. Is quite large.

Comparative Example 3 is an example of a chemical-mechanical polishing water-based dispersion that uses small-diameter alumina particles that are not coated with a silane compound as abrasive particles. In this case, in the defect evaluation, the defect rate of the substrate after polishing was smaller than that of the large-diameter alumina particles (Comparative Example 1) that were not coated with a silane compound coating, but they were comparable to the polymer-coated alumina Compared with the abrasive grains (Example 1), the defect rate was large.

Comparative Example 4 is an example in which an alumina abrasive particle dispersion liquid coated with a coating of a silane compound of calcined alumina AA-04 of Sumitomo Chemical was used as abrasive particles in the same manner as the synthesis method of Example 1. The XRF half-value width is 0.2685, which is smaller than the example, and it is estimated that the crystal unit is larger than that of the other examples. Therefore, the defect rate increased significantly to 250%. In addition, the stability of the dispersion significantly deteriorates.

The present invention is not limited to the above-mentioned embodiment, and various modifications are possible. For example, the present invention includes substantially the same structure as the structure described in the embodiment (for example, a structure having the same function, method, and result, or a structure having the same purpose and effect). In addition, the present invention includes a configuration in which non-essential parts of the configuration described in the embodiments are replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as those described in the embodiments 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 embodiments.

10: Alumina particles (nuclear department) 20: Coating of silane compound (coating, shell) 100: Alumina abrasive grains for chemical mechanical polishing (alumina abrasive grains)

FIG. 1 is a cross-sectional view schematically showing alumina abrasive grains for chemical mechanical polishing according to this embodiment.

10: Alumina particles (core section)

20: Coating of silane compound (coating, shell)

100: Alumina abrasive grains for chemical mechanical polishing (alumina abrasive grains)

Claims (8)

Alumina abrasive grains for chemical mechanical polishing, which are alumina abrasive grains at least a part of the surface of which is coated with a coating of a silane compound, wherein the molar number of silicon in the alumina abrasive grains is M _Si , and aluminum When the mole number of M is set to M _Al , the value of M _Si /M _Al is 0.01 or more and 0.2 or less, and the diffraction intensity of the powder X-ray diffraction pattern changes within the range of the incident angle of 25° or more and 75° or less The half-value width of the largest peak portion is 0.3° or more and 0.5° or less. The alumina abrasive grains for chemical mechanical polishing as described in item 1 of the patent application have an average primary particle diameter of 30 nm or more and 300 nm or less. The alumina abrasive grains for chemical mechanical polishing as described in item 1 or 2 of the patent application range, wherein the film thickness of the coating of the silane compound is 1 nm or more and 10 nm or less. The alumina abrasive grains for chemical mechanical polishing as described in any one of claims 1 to 3 are used for polishing a tungsten-containing substrate. Alumina abrasive grains for chemical mechanical polishing as described in item 4 of the patent application scope, wherein the substrate further contains silicon nitride, silicon dioxide, amorphous silicon, copper, cobalt, titanium, ruthenium, titanium nitride And more than one of tantalum nitride. A method for manufacturing alumina abrasive particles for chemical mechanical grinding, including: The half-value width of the peak portion where the average primary particle diameter is 10 nm or more and 1000 nm or less, and the powder X-ray diffraction pattern has the maximum diffraction intensity in the range of the incident angle of 25° or more and 75° or less is Step (a) of preparing α-alumina particle aqueous dispersion liquid having a solid content concentration of 1% by mass or more and 30% by mass or less in which α-alumina particles of 0.3° or more and 0.5° or less are dispersed in water; The step (b) of adding an alkoxysilane compound of 1 part by mass or more and 50 parts by mass or less when the total amount of the α-alumina particles is 100 parts by mass to the aqueous dispersion of α-alumina particles (b) );and The step (c) of growing the silane compound film on the surface of the α-alumina particles. The method for manufacturing alumina abrasive grains for chemical mechanical polishing as described in item 6 of the patent application scope, wherein the step (c) is performed at a temperature of 90°C or lower. The method for manufacturing alumina abrasive grains for chemical mechanical polishing as described in item 6 or item 7 of the patent application scope further includes adding ammonia in the step (a).

Images