JP2002030273A - Abrasive fluid composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an abrasive fluid composition which can increase an abrasive speed, lowers the surfaces roughness as well as the roll-off without occurrence of surface defects, a method of grinding the substrate with the composition and a method of producing semiconductor substrates. SOLUTION: This abrasive fluid composition comprises abrasive material, a roll off-reducing agent and alumina wherein the roll off-reducing agent is one or more selected from the group consisting o OH- or SH group having 2-20C carboxylic acids, 1-20C monocarboxylic acids, 2-3C dicarboxylic acids and their salts. In addition, this invention relates to a method of grinding semiconductor substrates by using this grind-finishing fluid composition and a method of producing semiconductor substrates by grinding the substrate with the fluid composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polishing composition. Further, the present invention relates to 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, pits, etc., and a polishing composition using water, alumina, boehmite and a chelating compound. (Japanese Patent Laid-Open No. 11-92749), a polishing liquid composition containing water, α-alumina, and an alumina sol stabilized with acetic acid (Japanese Patent 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.

[0004] However, these mechanical polishing conditions for reducing the roll-off are effective, but still insufficient, and the composition of the polishing liquid capable of reducing the roll-off has not been studied. It is the current situation.

[0005]

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

[0006]

That is, the gist of the present invention is as follows.
[1] A polishing liquid comprising water, an abrasive, a roll-off reducing agent and an intermediate alumina, wherein the roll-off reducing agent has an OH group or an SH group and has 2 to 20 carbon atoms; 1 selected from the group consisting of monocarboxylic acids having from 20 to 20, dicarboxylic acids having 2 to 3 carbon atoms and salts thereof.
[2] A method for polishing a substrate to be polished by polishing the substrate using the polishing composition according to [1], [3] A polishing composition according to [1]. The present invention relates to a method of manufacturing a substrate for polishing a substrate to be polished using an object.

[0007]

DETAILED DESCRIPTION OF THE INVENTION The polishing composition of the present invention is a polishing composition containing water, an abrasive, a roll-off reducing agent and an intermediate alumina, wherein the roll-off reducing agent is an OH group or SH group. A carboxylic acid having 2 to 20 carbon atoms, having 1 carbon atom
And at least one member selected from the group consisting of monocarboxylic acids having from 20 to 20, dicarboxylic acids having from 2 to 3 carbon atoms, and salts thereof.

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, 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 obtained as a number average particle size by observing (preferably 3000 to 30,000 times) with a scanning electron microscope, analyzing the image, and measuring the 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, and more preferably from 2 to 5, from the viewpoints of dispersibility, supply to a polishing apparatus, and recovery and reuse.

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

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. Here, the term "roll-off" generally means that the end surface of the substrate to be polished is more sharply cut and rounded than the central portion during polishing, and is also referred to as an end surface.

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 from 1 to 20, preferably from 1 to 12, more preferably from 1 to 8, still more preferably from 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.

OH group 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 the 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 monocarboxylic acids having 1 to 20 carbon atoms, dicarboxylic acids having 2 to 3 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.

The content of the roll-off reducing agent is preferably from 0.01 to 5% by weight, more preferably from 0.015 to 4% by weight, more preferably from 0.015 to 4% by weight, in the polishing composition from the viewpoint of reducing roll-off and from an economical viewpoint. Preferably 0.03 to 2% by weight
It is. In addition, the roll-off reducing agent can be used alone or in combination of two or more.

The term “intermediate alumina” used in the present invention is a general term for alumina particles other than α-alumina particles, and specifically includes γ-alumina particles, δ-alumina particles, θ-alumina particles, and η-alumina particles. Alumina particles, κ-alumina particles, mixtures thereof and the like can be mentioned. Among them,
The following intermediate aluminas are preferred from the viewpoints of the polishing rate improvement and the surface roughness reduction effect. Its crystal form is preferably γ
-Alumina, δ-alumina, θ-alumina and mixtures thereof. The specific surface area (BET method) is preferably 30 to 300 m ² / g, more preferably 50 to 20 m ² / g.
0 m ² / g. The average particle size is preferably 0.01 to
The thickness is 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 (for example, LA-920 manufactured by Horiba). The contents of the alkali metal and the alkaline earth metal in the intermediate alumina particles are each 0.1.
It is preferably at most 1% by weight, more preferably at most 0.05% by weight, particularly preferably at most 0.01% by weight.

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.

As a raw material for this purpose, 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.

When these intermediate aluminas are used in combination with the abrasive and the roll-off reducing agent, it is possible to improve the polishing rate, prevent surface defects such as pits, and promote the reduction of surface roughness.

The content of the intermediate alumina in the polishing composition is 100 parts by weight of the abrasive from the viewpoints of economical efficiency, the effect of promoting polishing, the effect of reducing surface roughness, and the ability to prevent surface defects such as pits. 1 to 100 parts by weight, preferably 2 to 70 parts by weight, more preferably 4 to 100 parts by weight,
40 parts by weight.

The water in the polishing composition of the present invention is used as a medium. The content of the water is preferably 40% from the viewpoint of efficiently polishing the object to be polished.
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.

As other components, organic acids and salts thereof other than the roll-off reducing agent, for example, organic acids and salts thereof such as polycarboxylic acids, aminopolycarboxylic acids and amino acids, inorganic acids and salts thereof, An oxidizing agent, a thickener, a dispersing agent, a rust inhibitor, a basic substance, a surfactant and the like can be mentioned. Specific examples of organic acids and salts thereof, inorganic acids and salts thereof, and oxidizing agents include JP-A-62-25187, page 2, upper right column, lines 3 to 11,
JP-A-63-251163, page 2, lower left column, lines 7 to 14;
No. 1-205973, page 3, upper left column, line 11 to upper right column, line 2,
No. 115383, page 2, lower right column, line 16 to page 3, upper left column, line 11,
No. 4-108887, page 2, lower left column, lines 1 to 9; JP-A-4-275387
No. 2, page 27, right column, line 27 to page 3, left column, line 12, and JP-A-4-363385, page 2, right column, lines 21 to 30.

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 expressing the respective functions and the viewpoint of economy, preferably, the content of the roll-off reducing agent composition is 0.05 to 2%.
0% by weight, more preferably 0.05 to 10% by weight, still 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 can be produced by appropriately adding and mixing the above-mentioned polishing agent, roll-off reducing agent, intermediate alumina, water and, if necessary, various additives by a known method. it can.

It is preferable that the pH of the polishing composition is appropriately determined depending on 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, or 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. For example, a shape having a flat portion such as a disk, a plate, a slab, or a prism, or a shape having a curved surface such as a lens is used in the present invention. 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. Among magnetic disk substrates, it is particularly suitable for polishing an Ni-P plated aluminum magnetic disk substrate.

As a method of manufacturing a substrate 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 of an organic polymer polishing cloth or the like is stuck. The polishing liquid composition is supplied to a polishing surface, and a polishing plate or a substrate is moved while applying a constant pressure, whereby a roll-off or surface roughness is reduced, and a method for producing a substrate free from surface defects can be mentioned.

In the present invention, the roll-off generated on the substrate to be polished is measured, for example, by using a stylus type or optical shape measuring device, and the profile of the end surface is compared to the center of the disk from the profile. It can be evaluated by quantifying how much is removed.

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 which are 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 edge and the center 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.

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. Also, oxalic acid, malic acid, tartaric acid,
In the polishing composition containing one or more of citric acid, gluconic acid and salts thereof, clogging of the polishing pad with abrasive grains and polishing residues is further reduced, and the polishing rate is increased by using the polishing pad for a long time. This is preferable because deterioration of polishing characteristics such as surface quality and surface quality can be prevented.

In this case, among the above compounds, 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 of the above compounds are used in combination, a particularly preferred combination is selected from oxalic acid, tartaric acid, citric acid and salts thereof.
A combination of at least one or oxalic acid, tartaric acid, citric acid and one or more selected from salts thereof and malonic acid;
A combination with at least one selected from glycolic acid, lactic acid, malic acid, gluconic acid and salts thereof is preferred,
Further, citric acid or a salt thereof and oxalic acid, glycolic acid,
1 selected from lactic acid, malic acid, tartaric acid and their salts
Combinations with more than one species are more preferred. A particularly preferred combination is citric acid or a salt thereof and glycolic acid or a salt thereof.

The polishing composition of the present invention is particularly effective in the polishing step, but can be similarly applied to other polishing steps, for example, a lapping step.

[0047]

[Example] <Intermediate alumina production example 1> Average particle size 25μ
m, specific surface area 250 m ² / g, alkali metal content 0.0
100 g of pseudo-boehmite particles having a weight of 03% by weight and an alkaline earth metal content of 0.01% by weight are placed in an alumina container (200 × 100 × 100 mm), heated in a muffle furnace at a heating rate of 50 ° C./min, and fired at a temperature of 930. 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, and ion-exchanged water was added to form a 30% by weight slurry. Then, 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, and had an average particle size of 0.3 μm, a specific surface area of 150 m ² / g, an alkali metal content of 0.005% by weight, and an alkaline earth metal content of 0.1%. It was 01% by weight.

Examples 1 to 6 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 0.8 μm (purity: about 99.9%)), roll-off Reducing agent, the intermediate alumina obtained in Production Example 1 (γ-
Alumina) and the balance of ion-exchanged water were adjusted to have the compositions shown in Table 1. Examples 1 to 5 and Comparative Examples 2, 3, and 5 were made of aqueous ammonia, and Comparative Examples 1 and 4 were made of nitric acid and adjusted to pH 4 with nitric acid. .0
, And mixed and stirred to prepare 100 parts by weight of a polishing composition.

[0049]

[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 with 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.

Further, the surface roughness (center line average roughness Ra), pits and roll-off of each substrate after polishing were measured according to the following methods. The center line average roughness Ra was determined as a relative value (relative roughness) with reference to Comparative Example 1. The roll-off was determined as a relative value (relative roll-off) based on the roll-off value of Comparative Example 2. Table 2 shows the results.

[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 an optical microscope (differential interference microscope), the surface of each substrate was observed at 12 points at 30 ° intervals at a magnification of × 200, and the number of pits was counted. 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 Radius of stylus tip: 2 μm (code No. 178-381) Stylus pressure: 0.7 mN or less Speed: 0.2 mm / s Analysis software: SV-600 fine contour analysis system
ratio1.01 filter: LPF (Gaussian) 0.800mm

Using the above apparatus, the shape of the end of the disk at a distance from the center of the disk of 42.5 mm to 47.5 mm 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.

[0058]

[Table 2]

From the results shown in Table 2, the polishing compositions obtained in Examples 1 to 6 all have high polishing rates, and are particularly polished compared with the polishing compositions obtained in Comparative Examples 1 to 5. It can be seen that the surface roughness of the substrate is reduced, there is no surface defect, and the roll-off can be significantly reduced.

Using the polishing composition prepared in Example 5, Example 6, and Comparative Example 3, the polishing evaluation described above was repeated 20 times, and the 20th relative polishing speed was compared with the first relative polishing speed. When the speed ratio was measured as the clogging prevention performance, it was 0.91 for the polishing composition of Example 5, 0.90 for Example 6, and 0.50 for Comparative Example 3. It can be seen that the polishing liquid compositions of Examples 5 and 6 have better polishing pad clogging prevention properties than those of Comparative Example 3.

[0061]

By using the polishing composition of the present invention for polishing a substrate for precision parts or the like, not only the roll-off and surface roughness of the substrate are significantly reduced, but also there are no surface defects and the polishing rate is reduced. The effect that it can also improve is produced.

[Brief description of the drawings]

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

Claims (3)

[Claims] 1. A polishing liquid comprising water, an abrasive, a roll-off reducing agent and an intermediate alumina, wherein the roll-off reducing agent is a carboxylic acid having 2 to 20 carbon atoms having an OH group or an SH group. Monocarboxylic acid of number 1 to 20, carbon number 2
A polishing liquid composition which is at least one selected from the group consisting of dicarboxylic acids and salts thereof. 2. A method for polishing a substrate to be polished by polishing the substrate to be polished using the polishing composition according to claim 1. 3. The polishing liquid composition according to claim 1,
A method for manufacturing a substrate, comprising a step of polishing a substrate to be polished.