JP2002012855A - Abrasive liquid composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an abrasive liquid composition capable of improving a polishing rate, decreasing surface roughness and reducing roll-off without causing a surface defect on the surface of a substrate to be polished, to provide a method for polishing the substrate to be polished using the abrasive liquid composition and a method for producing the substrate using the abrasive liquid composition. SOLUTION: This abrasive liquid composition comprises one or more kinds selected from a compound group (A) [an OH group or SH group-containing 2-20C carboxylic acid, a 2-3C dicarboxylic acid, a 1-20C monocarboxylic acid and their salts], one or more kinds selected from a compound group (B) [a>=4C polyfunctional carboxylic acid containing neither an OH nor an SH group, an aminopolycarboxylic acid, an amino acid and their salts] and one ore more kinds selected from a compound group (C) [intermediate alumina and alumina sol], an abrasive and water. This method for polishing a substrate to be polished comprises polishing the substrate to be polished by using the abrasive liquid composition. This method for producing the substrate comprises having a process for polishing the substrate to be polished by using the abrasive liquid composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polishing composition, a method for polishing a substrate to be polished using the polishing composition, and a method for producing a substrate using the polishing composition.

[0002]

2. Description of the Related Art Hard disks are becoming smaller and have higher capacities year by year, and their density is increasing, the minimum recording area is getting smaller, and the flying height of the magnetic head is getting smaller. In a polishing process of a hard disk substrate, it is required to improve a polishing rate, reduce surface roughness, and reduce surface defects such as scratches and pits. A polishing liquid composition using water, alumina, boehmite and a chelating compound ( Japanese Patent Application Laid-Open No. Hei 11-92749), a polishing composition containing water, α-alumina, and an alumina sol stabilized with acetic acid (Japanese Patent Application Laid-Open No. 2000-63805), and a polishing method are being studied.

On the other hand, in order to increase the capacity, in order to reduce the roll-off (slipping of the end face of the substrate) generated in the polishing process and develop a substrate capable of recording to the outer peripheral portion, the polishing pad is hardened and the polishing load is reduced. Such mechanical polishing conditions are being studied.

However, although the mechanical polishing conditions for reducing the roll-off are effective to some extent, they are still insufficient, and no study has been made on the composition of a polishing liquid capable of reducing the roll-off. is the current situation.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polishing method capable of improving the polishing rate, reducing the surface roughness and reducing the roll-off without causing surface defects on the surface of the substrate to be polished. It is an object of the present invention to provide a liquid composition, a method for polishing a substrate to be polished using the polishing liquid composition, and a method for manufacturing a substrate using the polishing liquid composition.

[0006]

That is, the gist of the present invention is as follows: [1] At least one compound selected from the following compound group (A), compound group (B) and compound group (C): And a water-containing polishing composition: Compound group (A): having 2 to 2 carbon atoms having an OH group or an SH group.
20 carboxylic acids, 2 to 3 carbon atoms of dicarboxylic acid, 1 to 20 carbon atoms of monocarboxylic acid and salts thereof, Compound group (B): a polyvalent carboxylic acid having no OH group or SH group having 4 or more carbon atoms Acids, aminopolycarboxylic acids, amino acids and salts thereof, compound group (C): intermediate alumina and alumina sol, [2] polishing of a substrate to be polished using the polishing composition according to [1]. The present invention relates to a polishing method, and [3] a method for producing a substrate having a step of polishing a substrate to be polished using the polishing composition according to [1].

[0007]

DETAILED DESCRIPTION OF THE INVENTION As described above, the polishing composition of the present invention comprises at least one compound selected from the group consisting of the compound group (A), the compound group (B) and the compound group (C), , Water.

The compound group (A) used in the present invention is a compound having a function of improving roll-off occurring on a substrate to be polished (hereinafter also referred to as a roll-off reducing agent). Roll-off generally means that the end face portion is more sharply cut and rounded than the center portion during polishing, and is also referred to as an end face droop. Roll-off is evaluated, for example, by measuring the shape of the end face part using a stylus or optical shape measuring device and quantifying how much the end face part is shaved compared to the center of the disc from its profile can do.

As shown in FIG. 1, the method of digitization is to use three points on a measurement curve (meaning the shape of the end face portion of the substrate to be polished) such as points A, B and C at a certain distance from the center of the disk. A point is taken, a straight line connecting point A and point C is taken as a baseline, and the distance (D) between point B and the baseline is referred to. Good roll-off means that the value of D is closer to zero. The roll-off value is a value obtained by dividing D by の of the change in the thickness of the disk before and after polishing. The roll-off value is preferably 0.2 μm / μm or less, more preferably 0.15 μm / μm, and still more preferably 0.10 μm / μm.
μm.

The positions of point A, point B and point C vary depending on the size of the object to be measured. In general, point B is located on a line connecting the end of the disk and the center from the end of the disk at 0. 5
mm position, C point is 2.5 mm position, A point is 4.5 m
Preferably, the position is m. For example, in the case of a 3.5-inch disk, it is preferable that points A, B, and C are respectively 43 mm, 47 mm, and 45 mm from the center of the disk.

The roll-off reducing agent used in the present invention comprises:
1 selected from the group consisting of a carboxylic acid having 2 to 20 carbon atoms having an OH group or an SH group, a monocarboxylic acid having 1 to 20 carbon atoms, a dicarboxylic acid having 2 to 3 carbon atoms and salts thereof.
More than one compound.

2 to 20 carbon atoms having an OH or SH group
Examples of the carboxylic acid include oxycarboxylic acid and compounds in which the oxygen atom of the OH group of the acid is replaced with a sulfur atom. From the viewpoint of solubility in water, the number of carbon atoms of these carboxylic acids is 2 to 20, preferably 2 to 12, more preferably 2 to 8, and further preferably 2 to 6. From the viewpoint of reducing roll-off, the oxycarboxylic acid preferably has a hydroxyl group at the α-position of the carboxyl group.

The number of carbon atoms of the monocarboxylic acid is 1 to 20, preferably 1 to 12, more preferably 1 to 8, and further preferably 1 to 6, from the viewpoint of solubility in water. .

The dicarboxylic acids are those having 2 to 3 carbon atoms, that is, oxalic acid and malonic acid, from the viewpoint of reducing roll-off. Among these roll-off reducing agents, oxycarboxylic acids are preferred from the viewpoint of improving the polishing rate. Further, from the viewpoint of reducing roll-off, dicarboxylic acids are preferred.

An OH or SH group having 2 to 20 carbon atoms
Specific examples of the carboxylic acid include glycolic acid, mercaptosuccinic acid, thioglycolic acid, lactic acid, β-hydroxypropionic acid, malic acid, tartaric acid, citric acid, isocitric acid, allocitric acid, gluconic acid, glyoxylic acid,
Glyceric acid, mandelic acid, tropic acid, benzylic acid, salicylic acid and the like can be mentioned. Specific examples of monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, hexanoic acid, heptanoic acid, 2-methylhexanoic acid, octanoic acid, 2-ethylhexanoic acid, and nonane Acids, decanoic acid, lauric acid and the like. Among these, acetic acid, oxalic acid, malonic acid, glycolic acid, lactic acid,
Malic acid, tartaric acid, glyoxylic acid, citric acid and gluconic acid are preferred, and oxalic acid, malonic acid, glycolic acid, lactic acid, malic acid, tartaric acid, glyoxylic acid, citric acid and gluconic acid are more preferred.

Further, oxalic acid, malic acid, tartaric acid, citric acid and gluconic acid can be used alone or in combination with another roll-off reducing agent to further reduce clogging of abrasive grains and polishing residues on the polishing pad. This is preferable because it is possible to prevent polishing characteristics such as polishing rate and surface quality from deteriorating due to long-term use of the polishing pad. Further, frequent pad cleaning is not required, that is, the interval between pad dressings can be greatly extended, and productivity is improved, which is excellent in terms of economy, and is therefore preferable. Among them, oxalic acid, tartaric acid and citric acid are preferable, and citric acid is particularly preferable. In addition,
The monocarboxylic acid and dicarboxylic acid used in the present invention are selected from carboxylic acids having no OH group or SH group.

Further, salts of these acids (ie, salts of carboxylic acids having 2 to 20 carbon atoms having an OH group or SH group, salts of dicarboxylic acids having 2 to 3 carbon atoms, monocarboxylic acids having 1 to 20 carbon atoms) The acid salt is not particularly limited, and specific examples thereof include salts with metals, ammonium, alkylammonium, organic amines, and the like. Specific examples of metals include
Periodic table (long period type) 1A, 1B, 2A, 2B, 3A,
Metals belonging to groups 3B, 4A, 6A, 7A or 8 are mentioned. Among these metals, metals belonging to groups 1A, 3A, 3B, 7A or 8 are preferable from the viewpoint of roll-off reduction, metals belonging to groups 1A, 3A or 3B are more preferable, and sodium and potassium belonging to group 1A are most preferable. preferable.

Specific examples of the alkyl ammonium include:
Examples include tetramethylammonium, tetraethylammonium, and tetrabutylammonium.

Specific examples of the organic amine and the like include dimethylamine, trimethylamine and alkanolamine.

Among these salts, ammonium salts, sodium salts and potassium salts are particularly preferred.

These compounds of the compound group (A) can be used alone or in combination of two or more.

The total content of the compound group (A) is preferably 0.01 to 5% by weight, more preferably 0.015 to 3% by weight in the polishing composition from the viewpoint of the effect of improving roll-off and from the economical viewpoint. Wt%, more preferably 0.03 to 2
% By weight.

The compound group (B) used in the present invention has an effect of improving the polishing rate. As the compound group (B),
Examples include polyvalent carboxylic acids having no OH group or SH group having 4 or more carbon atoms, aminopolycarboxylic acids, amino acids, and salts thereof. From the viewpoint of speed improvement, O having 4 or more carbon atoms
Among polyvalent carboxylic acids having no H group or SH group, those having 4 to 20 carbon atoms are preferable, and those having 4 to 10 carbon atoms are more preferable. In addition, from the same viewpoint, as the aminopolycarboxylic acid, the number of amino groups in one molecule is preferably from 1 to 6, and more preferably from 1 to 4. Further, the number of carboxylic acids is preferably from 1 to 12, more preferably from 2 to 8.
Further, the number of carbon atoms is preferably 1 to 30, more preferably 1 to 30.
20 is preferred. From the same viewpoint, the carbon number of the amino acid is preferably from 2 to 20, and more preferably from 2 to 10.

Specifically, succinic acid, maleic acid, fumaric acid, glutaric acid, citraconic acid, itaconic acid, tricarbalic acid, adipic acid, propane-1,1,2,3-tetracarboxylic acid, butane-1,2 , 3,4-tetracarboxylic acid, diglycolic acid, nitrotriacetic acid, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), hydroxyethylethylenediaminetetraacetic acid (HEDTA), triethylenetetraminehexaacetic acid (TTHA), Carboxymethylglutamic acid (GLDA), glycine, alanine and the like. Among these, succinic acid, maleic acid, fumaric acid, glutaric acid, citraconic acid, itaconic acid, tricarbalic acid, adipic acid, diglycolic acid, nitrotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid are preferred, and further succinic acid, maleic acid , Fumaric acid, citraconic acid, itaconic acid, tricarbalic acid, diglycolic acid, ethylenediaminetetraacetic acid,
Diethylenetriaminepentaacetic acid is more preferred.

Also, salts of these acids (O 4 or more carbon atoms)
The salt of a polyvalent carboxylic acid having no H group or SH group, the salt of an aminopolycarboxylic acid, and the salt of an amino acid are not particularly limited, and specific examples thereof include metals, ammonium, alkylammonium, and organic amines. Salts. Specific examples of the metal include periodic table (long period type) 1A, 1B,
Examples include metals belonging to Group 2A, 2B, 3A, 3B, 4A, 6A, 7A or Group 8. Among these metals, metals belonging to Group 1A, 3A, 3B, 7A or 8 are preferable from the viewpoint of improving the polishing rate, and metals belonging to Group 1A, 3A, 3B or 8 are more preferable, and sodium and potassium belonging to Group 1A. Cerium belonging to Group 3A, aluminum belonging to Group 3B, and iron belonging to Group 8 are most preferred.

Specific examples of the alkyl ammonium include:
Examples include tetramethylammonium, tetraethylammonium, and tetrabutylammonium.

Specific examples of the organic amine include dimethylamine, trimethylamine, and alkanolamine. Among these, ammonium salts, sodium salts, potassium salts and aluminum salts are particularly preferred as the salts.

These compounds of the compound group (B) can be used alone or in combination of two or more.

The total content of the compound group (B) is preferably from 0.01 to 10% by weight, more preferably from 0.02 to 10% by weight in the polishing composition from the viewpoint of the polishing accelerating effect, the economical viewpoint and the surface quality improvement. 7% by weight, more preferably 0.03-5
% By weight.

The combination of the compound group (A) and the compound group (B) may be selected from the group consisting of acetic acid, oxalic acid, malonic acid, glycolic acid, lactic acid, malic acid and glyoxyl from the viewpoints of improving speed and reducing roll-off. One or more of acid, tartaric acid, citric acid, gluconic acid and salts thereof (compound group (A)) and succinic acid, maleic acid, fumaric acid, glutaric acid, citraconic acid, itaconic acid, adipic acid, tricarbalic acid, dicarboxylic acid More preferred is a combination of glycolic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid and one or more of these salts (compound group (B)), and oxalic acid, malonic acid, glycolic acid, lactic acid, malic acid, glyoxylic acid , Tartaric acid, citric acid, gluconic acid and one or more of these salts [compound group (A)] with succinic acid, Ynoic acid, fumaric acid, citraconic acid, itaconic acid, Torikarubaru acid, diglycolic acid,
At least one of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid and salts thereof [compound group (B)]
Is more preferable. Further, at least one of glycolic acid, oxalic acid, tartaric acid, citric acid, malonic acid and salts thereof (compound group (A)) and succinic acid, maleic acid, itaconic acid, fumaric acid, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid And combinations of one or more of these salts [compound group (B)]. Also, as compound group (A), oxalic acid, malic acid,
When one or more of tartaric acid, citric acid, gluconic acid and salts thereof are used, the clogging of abrasive grains and polishing debris on the polishing pad is further reduced, and the polishing speed and surface area due to long-term use of the polishing pad are reduced. This is preferable because deterioration of polishing characteristics such as quality can be prevented.

In this case, among the above compound group (A), oxalic acid, tartaric acid, citric acid or a salt thereof is preferable, and citric acid or a salt thereof is particularly preferable. When two or more compound groups (A) are used in combination, a particularly preferable combination is a combination of two or more selected from oxalic acid, tartaric acid, citric acid and salts thereof, or oxalic acid, tartaric acid, citric acid And a combination of at least one selected from malonic acid, glycolic acid, lactic acid, malic acid, gluconic acid and salts thereof, and further preferably citric acid or a salt thereof with oxalic acid , Glycolic acid, lactic acid, malic acid, tartaric acid and a combination thereof with one or more thereof are more preferable. A particularly preferred combination is citric acid or a salt thereof and glycolic acid or a salt thereof.

In the compound group (C) used in the present invention, the term “intermediate alumina” is a general term for alumina particles other than α-alumina particles.
δ-alumina particles, θ-alumina particles, η-alumina particles, κ-alumina particles, and mixtures thereof. Among them, the following intermediate aluminas are preferred from the viewpoint of improving the polishing rate and reducing the surface roughness. The crystal form is preferably γ-alumina, δ-alumina, θ-alumina and a mixture thereof, more preferably, γ-alumina, δ-alumina, and a mixture thereof, particularly preferably,
γ-alumina. The specific surface area (BET method)
Is preferably from 30 to 300 m ² / g, more preferably from 50 to ²⁰⁰ m ² / g. The average particle size is preferably 0.01 to 5 μm, more preferably 0.05 to 5 μm, still more preferably 0.1 to 3 μm, particularly preferably 0.1 to 1.5.
μm. This average particle diameter can be measured as a volume average particle diameter using a laser light diffraction method (for example, LA-920 manufactured by Horiba). The content of the alkali metal and alkaline earth metal in the intermediate alumina particles is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and particularly preferably 0.01% by weight or less.

For example, when aluminum hydroxide, alumina sol, or the like having a relatively large specific surface area and a low alkali metal and alkaline earth metal content is used as a raw material, the produced intermediate alumina has low fusion and low particle strength. ,
There is no surface defect on the substrate to be polished, which is particularly effective for reducing the surface roughness.

The raw material for this is the chemical formula Al (O
H) ₃ , Al ₂ O ₃ .3H ₂ O, AlOOH, Al ₂ O
_{3 · H 2 O, Al 2} O 3 · nH 2 O [n denotes 1-3] represented by, for example, aluminum hydroxide, alumina sol and the like can be used, is preferably a specific surface area of the material 10 m ² / G or more, more preferably 30 m ² / g
Above, particularly preferably 50 m ² / g or more.
Further, the content of the alkali metal and the alkaline earth metal is preferably 0.1% by weight or less, more preferably 0.05% by weight or less, and particularly preferably 0.03% by weight or less. Furthermore, when heating and dehydrating aluminum hydroxide to produce an intermediate alumina, forcibly introducing dry air or nitrogen gas during firing is more effective in reducing surface defects and surface roughness of the substrate to be polished. It is. still,
The heat dehydration treatment can be performed by a conventional method.

These intermediate aluminas may be used, if necessary,
Wet or dry pulverization is performed by a pulverizer such as a ball mill, a bead mill, a high-pressure homogenizer, and a jet mill to adjust the particle size to a predetermined value.

Alumina sol is a chemical formula of Al
OOH, AlOOH · nH ₂ O (n represents 1-3),
It is represented by Al ₂ O ₃ .H ₂ O or the like, and its crystal structure includes boehmite, pseudo-boehmite and amorphous. Aluminum hydroxide, such as gibbsite, is
It can be produced by hydrothermal treatment at about ° C or hydrolysis of aluminum alcoholate. The average particle size is preferably 0.01 to 5 μm, more preferably 0.05 to 5 μm, still more preferably 0.1 to 3 μm, and particularly preferably 0.1 to 1.5 μm. This average particle diameter can be measured as a volume average particle diameter using a laser light diffraction method. Its specific surface area (BET method) is preferably 30 to 300 m ² / g, more preferably 50 to 200 m ² / g.
² / g.

The intermediate alumina and the alumina sol of the compound group (C) are used in combination with the compounds of the compound group (A) and the compound group (B) to further enhance the polishing rate and prevent surface defects such as pits. be able to. In this case, the intermediate alumina and the alumina sol of the compound group (C) may be used alone or as a mixture. In particular, the intermediate alumina is more preferable from the viewpoints of the effects of improving the polishing rate, preventing surface defects, and the like, and further reducing the surface roughness.

The total content of the compound group (C) in the polishing composition is determined from the viewpoints of economy, polishing promotion effect, surface roughness reducing effect, and ability to prevent surface defects such as pits. The amount is 1 to 100 parts by weight, preferably 2 to 70 parts by weight, more preferably 4 to 40 parts by weight with respect to 100 parts by weight of the abrasive.

As the abrasive used in the present invention, an abrasive generally used for polishing can be used. Examples of the abrasive include metal; metal or metalloid carbide,
Nitrides, oxides, borides; diamonds and the like. Metal or metalloid elements are listed in the Periodic Table (Long Period Type)
A, 2B, 3A, 3B, 4A, 4B, 5A, 6A, 7A
Or, it is derived from Group 8. As a specific example of the abrasive, α
-Alumina particles, silicon carbide particles, diamond particles,
Examples include magnesium oxide particles, zinc oxide particles, cerium oxide particles, zirconium oxide particles, colloidal silica particles, fumed silica particles, and the like. Use of one or more of these is preferred from the viewpoint of improving the polishing rate. Among them, α-alumina particles, cerium oxide particles, zirconium oxide particles, colloidal silica particles, fumed silica particles, and the like are more preferable, and α-alumina particles are particularly preferable.

The average particle size of the primary particles of the abrasive is preferably from 0.01 to 3 μm, more preferably from 0.02 to 0.8 μm, and particularly preferably from 0.05 to 0.
5 μm. Further, when the primary particles are aggregated to form secondary particles, the average particle size of the secondary particles is similarly increased from the viewpoint of improving the polishing rate and reducing the surface roughness of the object to be polished. , Preferably 0.05 to 3 μm, more preferably 0.1 to 1.5 μm, particularly preferably 0.2 to 1.2 μm.
μm. The average particle size of the primary particles of the abrasive can be determined by observing with a scanning electron microscope (preferably 3000 to 30,000 times), analyzing the image, and measuring the average particle size. The average particle size of the secondary particles can be measured as a volume average particle size by using a laser light diffraction method.

The specific gravity of the abrasive is preferably from 2 to 6, more preferably from 2 to 5, from the viewpoints of dispersibility, supply to the polishing apparatus, and recovery and reuse.

The content of the abrasive is preferably from 1 to 40% by weight, more preferably from 40% by weight, in the polishing composition, from the viewpoints of economy, reduction of surface roughness, and efficient polishing. It is 2 to 30% by weight, more preferably 3 to 15% by weight.

The water in the polishing composition of the present invention is used as a medium, and its content is preferably 40% from the viewpoint of enabling the object to be polished to be polished efficiently.
It is preferably from 98 to 98% by weight, more preferably from 50 to 97% by weight, particularly preferably from 60 to 95% by weight.

The polishing composition of the present invention may contain other components, if necessary.

Other components include inorganic acids and salts thereof, oxidizing agents, thickeners, dispersants, rust inhibitors, basic substances, surfactants and the like.

These components may be used alone, or 2
A mixture of more than one species may be used. Also, its content is
From the viewpoint of improving the polishing rate, expressing each function, and economy, preferably 0.05 to 20% by weight, more preferably 0.05 to 20% by weight in the polishing composition.
It is 10% by weight, more preferably 0.05 to 5% by weight.

The concentration of each component in the polishing composition is a preferable concentration when polishing, but may be a concentration when the composition is manufactured. Usually, the composition is produced as a concentrated liquid, and this is often used after dilution.

The polishing composition of the present invention comprises the compound group (A), the compound group (B), the compound group (C), an abrasive,
It can be produced by appropriately adding and mixing water and, if necessary, various additives by a known method.

It is preferable that the pH of the polishing composition is appropriately determined according to the type of the object to be polished, required quality, and the like. For example, the pH of the polishing composition is preferably from 2 to 12, from the viewpoints of the cleaning property of the substrate, the corrosion prevention property of the processing machine, and the safety of the operator. Further, when the object to be polished is a substrate for precision parts mainly targeting a metal such as a Ni-P plated aluminum alloy substrate, from the viewpoint of improving the polishing rate and the surface quality, 2 to 9 is more preferable. And 3 to 8 are particularly preferred. Further, when used for polishing semiconductor wafers and semiconductor elements, particularly for polishing silicon substrates, polysilicon films, SiO ₂ films, etc., from the viewpoint of improving the polishing rate and improving the surface quality,
7-12 are preferable, 8-12 are more preferable, and 9-1
1 is particularly preferred. The pH is, if necessary, an inorganic acid such as nitric acid or sulfuric acid, an organic acid, ammonia, sodium hydroxide,
It can be adjusted by appropriately mixing a basic substance such as potassium hydroxide in a desired amount.

In the method of polishing a substrate to be polished according to the present invention, a polishing liquid is prepared by using the polishing liquid composition of the present invention or by mixing respective components so as to obtain the composition of the polishing liquid composition of the present invention. And a step of polishing the substrate to be polished, and particularly a substrate for precision parts can be suitably manufactured.

The material to be polished represented by the substrate to be polished, which is the object of the present invention, is, for example, a metal or semi-metal such as silicon, aluminum, nickel, tungsten, copper, tantalum or titanium, and a metal such as these. Examples include alloys, glass-like substances such as glass, glassy carbon and amorphous carbon, ceramic materials such as alumina, silicon dioxide, silicon nitride, tantalum nitride, and titanium nitride, and resins such as polyimide resins. Of these, metals such as aluminum, nickel, tungsten, and copper and alloys containing these metals as main components are the objects to be polished, or semiconductor substrates such as semiconductor elements containing such metals are objects to be polished. It is preferred that Especially when polishing a substrate made of Ni-P plated aluminum alloy,
The use of the polishing composition of the present invention is preferable because the roll-off is small, the polishing rate is improved, and the surface roughness can be reduced without causing surface defects.

The shape of the object to be polished is not particularly limited, and examples thereof include a shape having a flat surface such as a disk, a plate, a slab, and a prism, and a shape having a curved surface such as a lens. Of the polishing composition using the polishing composition. Among them, it is particularly excellent in polishing a disk-shaped object to be polished.

The polishing composition of the present invention is suitably used for polishing precision component substrates. For example, it is suitable for polishing a substrate of a magnetic recording medium such as a magnetic disk, an optical disk, and a magneto-optical disk, a photomask substrate, an optical lens, an optical mirror, an optical prism, and a semiconductor substrate. Polishing of a semiconductor substrate includes polishing performed in a polishing step of a silicon wafer (bare wafer), a step of forming a buried element isolation film, a step of flattening an interlayer insulating film, a step of forming a buried metal wiring, a step of forming a buried capacitor, and the like. The polishing composition of the present invention is particularly suitable for polishing a magnetic disk substrate.

As a method for producing a substrate to be polished using the polishing composition of the present invention, for example, the substrate to be polished is sandwiched by a polishing plate to which a nonwoven fabric-like organic polymer polishing cloth or the like is attached. Supplying the polishing composition of the present invention to a polishing surface,
There is a method of manufacturing a substrate to be polished by moving a polishing board or a substrate while applying a constant pressure.

As described above, by using the polishing composition of the present invention, the polishing rate was improved, the surface roughness was reduced, and the roll-off was reduced, without causing surface defects on the surface. High quality substrates can be manufactured with high production efficiency.

Although the polishing composition of the present invention is particularly effective in the polishing step, it can be similarly applied to other polishing steps such as a lapping step.

[0057]

[Example] <Example 1 of production of intermediate alumina> Average particle size 15μ
m, specific surface area 240 m ² / g, alkali metal content 0.0
100 g of pseudo-boehmite particles having a content of 02% by weight and an alkaline earth metal content of 0.01% by weight are placed in an alumina container (200 × 100 × 100 mm) and heated in a muffle furnace at a heating rate of 50 ° C./min and a baking temperature of 900. At 4 ° C. for 4 hours at a nitrogen flow rate of 5 L / min, an intermediate alumina was obtained. This was transferred to a 2L alumina ball mill, ion-exchanged water was added to make a 30% slurry, and alumina balls having a diameter of 3 mm were put therein and pulverized to prepare intermediate alumina particles. The prepared intermediate alumina particles were γ-alumina by X-ray diffraction peak analysis, the average particle size was 0.3 μm, the specific surface area was 120 m ² / g, and the alkali metal content was 0.00.
3% by weight, the alkaline earth metal content was 0.01% by weight.

Examples 1 to 8 and Comparative Examples 1 to 5 Abrasives (α-alumina having an average primary particle size of 0.25 μm and an average secondary particle size of 0.65 μm (purity: about 99.9%)), a compound group ( A), the compound group (B), the compound group (C) [intermediate alumina (γ-alumina) or alumina sol (boehmite) obtained in the above Production Example 1) and the balance with ion-exchanged water are as shown in Table 1. As described above, the pH was adjusted to 4.0 or 7.0 with nitric acid or aqueous ammonia, and mixed and stirred to prepare 100 parts by weight of the polishing composition.

[0059]

[Table 1]

Using the obtained polishing composition, the center line average roughness Ra measured by the following method was 0.2 μm and the thickness was 0.2 μm.
The surface of a 8 mm, 3.5 inch diameter Ni-P plated aluminum alloy substrate was polished by a double-sided processing machine under the following double-sided processing machine setting conditions, and the Ni-P plated used as a substrate for magnetic recording media A polished aluminum alloy substrate was obtained.

The setting conditions of the double-side processing machine are shown below. Double-side processing machine used: 9B type double-side processing machine manufactured by Speed Fam Co., Ltd. Processing pressure: 9.8 kPa Polishing pad: Polytex DG-H (manufactured by Rodel Nitta) Plate rotation speed: 55 r / min Polishing composition supply flow rate: 100 mL / min Polishing time: 4min Input number: 10

After polishing, the thickness of the aluminum alloy substrate was measured using a film thickness meter (manufactured by Mitutoyo Corporation, laser film thickness meter Model LGH-
110 / LHC-11N), the rate of decrease in thickness was determined from the change in thickness of the aluminum alloy substrate before and after polishing, and a relative value (relative polishing rate) was determined based on Comparative Example 1.

The surface roughness (center line average roughness Ra), pits and roll-off of the polished surface of each substrate were measured according to the following methods. Note that the center line roughness Ra was determined in Comparative Example 1.
, And a relative value (relative roughness) was determined. For the roll-off, a relative value (relative roll-off) was determined based on Comparative Example 2. Table 2 shows the results.

[Surface roughness (center line average roughness Ra)] Measured under the following conditions using a tally step manufactured by Rank Taylor Hobson. Stylus tip size: 25 μm × 25 μm High pass filter: 80 μm Measurement length: 0.64 mm

[Surface Defects (Pits)] Using optical microscope observation (differential interference microscope), the surface of each substrate was observed at 12 places at 30 ° intervals at a magnification of × 200, and the number of pits per 12 visual fields was counted. . Table 1 shows the results. The evaluation criteria in the table are shown below. S: 0 pieces A: 1 to 3 pieces B: 4 to 10 pieces C: 10 pieces or more

[Roll-off] Measuring device: Mitutoyo Form Tracer SV-C62
4 Contact tip radius: 2 μm (code No. 178-381) Contact pressure: 0.7 mN or less Speed: 0.2 mm / s Analysis software: SV-600 fine contour analysis system version1.0
1 Filter: LPF (Gaussian) 0.800mm

Using the above apparatus, the shape of the edge of the disk at a distance of 42.5 mm to 47.5 mm from the center of the disk was measured, and the positions of points A, B and C were respectively 43 mm, 47 mm and 45 mm from the center of the disk. Then, D was obtained by the above-described measurement method using analysis software. The value obtained by dividing the obtained D by 1/2 of the amount of change in the thickness of the disk before and after polishing was defined as a roll-off value.

[0068]

[Table 2]

From the results in Table 2, it can be seen that the polishing compositions obtained in Examples 1 to 8 are all superior to the polishing compositions obtained in Comparative Examples 1 to 5 in terms of the polishing rate improving effect, pits and the like. It can be seen that this is an excellent material that simultaneously satisfies all of the effect of reducing surface defects, the effect of reducing surface roughness, and the effect of reducing roll-off.

Further, Examples 5, 8 and Comparative Example 2
Using the polishing composition prepared in the above, the polishing evaluation described above was repeated 20 times, and 20 times the first relative polishing rate.
When the ratio of the relative polishing rate at the time of the polishing was measured as the clogging prevention performance, it was 0.91 for the polishing composition of Example 5, 0.90 for Example 8, and 0.48 for Comparative Example 2. Was. It can be seen that the polishing composition obtained in Examples 5 and 8 has better polishing pad clogging prevention properties than those of Comparative Example 2.

[0071]

By using the polishing composition of the present invention,
The polishing rate is improved, the surface roughness is reduced, and the roll-off is reduced without causing surface defects on the surface of the substrate to be polished.

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a measurement curve and roll-off.

Claims (5)

[Claims] 1. The following compound group (A) and compound group (B)
And one or more selected from the compound group (C),
Polishing liquid composition containing abrasive and water: Compound group (A): having 2 to 2 carbon atoms having OH group or SH group
20 carboxylic acids, 2 to 3 carbon atoms of dicarboxylic acid, 1 to 20 carbon atoms of monocarboxylic acid and salts thereof, Compound group (B): a polyvalent carboxylic acid having no OH group or SH group having 4 or more carbon atoms Acids, aminopolycarboxylic acids, amino acids and their salts, Compound group (C): intermediate alumina and alumina sol. 2. The polishing composition according to claim 1, wherein the intermediate alumina and the alumina sol of the compound group (C) have a specific surface area of 30 to 300 m ² / g and an average particle size of 0.01 to 5 μm. 3. The intermediate alumina has a specific surface area of 10 m ² / g.
3. The polishing composition according to claim 1, wherein the polishing composition is produced from aluminum hydroxide and / or alumina sol having a content of alkali metal and alkaline earth metal of 0.1% by weight or less. 4. A method for polishing a substrate to be polished, comprising polishing the substrate to be polished using the polishing composition according to claim 1. 5. A method for producing a substrate, comprising a step of polishing a substrate to be polished using the polishing composition according to claim 1.