JPH05112775A - Grinding composition for metallic material - Google Patents

Abstract

PURPOSE:To obtain a grinding composition which has grinding characteristics at least equivalent to those of conventional one, is used for grinding a metallic material such as a magnetic disc base material or a semiconductor substrate material, can perform excellent grinding having a low surface roughness and free from surface defects such as pits and nodules and is free from the problem of the corrosion of apparatuses, the chapping of hands, waste water disposal, etc. CONSTITUTION:The title composition comprises water and an alumina abrasive, wherein a fluorocarbon surfactant and an amino acid are further incorporated.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polishing composition for metal materials. More specifically, the present invention relates to a polishing composition used for precision polishing of magnetic disk substrate materials such as aluminum and nickel-based alloys, semiconductor substrate materials such as silicon and gallium arsenide, and other metal materials.

[0002]

Description of the Prior Art With the progress of electronics and computer industries, precision polishing of magnetic disk substrate materials such as aluminum and nickel-based alloys and metal materials such as semiconductor substrate materials such as silicon and gallium arsenide is very important technology. It is positioned as.

In recent years, recording density and integration density of magnetic disks and semiconductors have been increased, and even in precision polishing of these substrate materials, the surface smoothness and defect-free (scratch, orange peel, pit, The requirement level for (no nodules) is becoming more sophisticated. Therefore, the improvement of the precision polishing technology level has become a more important issue than ever before.

As a polishing composition generally used for precision polishing of metal materials, for example, alumina, silica, cerium oxide, zirconium oxide, iron oxide, chromium oxide, silicon carbide, diamond, etc. are used as abrasive grains. thing,
Alternatively, those obtained by suspending them in water to form a slurry are known. However, when these polishing compositions are used, surface defects such as pits and nodules are likely to occur on the polished surface.

Therefore, from the viewpoint of improving the surface smoothness of the polishing surface, an invention has been proposed in which a specific polishing accelerator is blended according to the object to be processed. For example, a pH consisting of water, an alumina abrasive, and a nickel sulfate polishing accelerator.
4 to 6 weakly acidic ones (Japanese Examined Patent Publication No. 64-436) and strongly acidic pH 2 to 4 consisting of water, an alumina abrasive and an aluminum nitrate polishing accelerator (Japanese Patent Publication No.
No. 23589).

Among these salts of a metal such as aluminum or nickel and an inorganic acid such as nitric acid or sulfuric acid, that is, a water-soluble metal salt, a strongly acidic polishing composition has a polishing rate higher than that of a weakly acidic polishing composition. Has the advantage that the polishing surface is high and the surface smoothness of the polishing surface is excellent, but on the other hand, it has the drawback that the equipment such as polishing equipment is easily corroded, and the risk of chemical damage such as rough skin on the skin and clothes of the operator. There is a problem that the property is high. In addition, due to environmental issues and the like, those using nitrate as a polishing accelerator have a problem of treating dissolved nitrogen in waste water.

On the other hand, the weakly acidic polishing composition is corrosive,
Although it does not have such problems as chemical damage as the strongly acidic polishing composition, it has a drawback that the polishing rate and the surface smoothness of the polishing surface are poor. In addition, regarding the surface smoothness of the polishing surface, it is the current situation that even if any of these polishing accelerators is used, it is not possible to meet the demanding level of sophistication, and it is equal to or higher than the conventional strongly acidic polishing composition There is a strong demand for a polishing composition which has the above-mentioned polishing characteristics and is capable of obtaining a polished surface having more excellent surface smoothness, less corrosion of the equipment and rough hands, and easy drainage treatment.

[0008]

In view of such circumstances, the present inventors have found that a polishing surface which has polishing characteristics equal to or higher than those of conventional polishing compositions, has a small surface roughness, and has no surface defects. As a result of diligent studies to obtain a polishing composition for a metal material that can be obtained, of course, there is no problem of corrosion, toxicity, wastewater treatment, etc., a polishing composition comprising a conventional water / alumina abrasive / water-soluble metal salt In the case where a fluorine-based surfactant is present instead of the water-soluble metal salt, it was found that a polishing composition for a metal material that can satisfy all the above objects can be obtained, and the application was filed as Japanese Patent Application No. 3-188655. did. However, as a result of further study, when the amino acid was simultaneously contained in the fluorosurfactant and allowed to exist therein, the polishing rate was lowered without lowering the surface characteristics of the polishing surface as compared with the case where the fluorosurfactant was used alone. They have found that they can be improved, and completed the present invention.

[0009]

[Means for Solving the Problems] That is, the present invention provides a polishing composition for a metal material comprising water and an alumina abrasive, wherein the composition contains a fluorosurfactant and an amino acid. Another object is to provide a polishing composition for a characteristic metal material.

The present invention will be described in more detail below. Starting
The fluorosurfactant used in Ming is a hydrophobic group.
As a hydrocarbon chain, not a full
Surfactants with fluorinated carbon chains
As long as it is fluoroalkyl (C₂~ C₂₀)
Carboxylic acid, perfluoroalkylcarboxylic acid (C₇~
C₁₃), Perfluoroalkyl (C _Four~ C₁₂) Carvone
Acid salt (Li, K, Na, NH_Four), Perfluoroalkyl
Le (C_Four~ C₁₂) Sulfonate (Li, K, Na, NH
_Four), Perfluorooctane sulfonic acid diethanol
Mid, perfluoroalkyl polyoxyethylene ethano
, 3- [ω-fluoroalkyl (C₆~ C₁₁) Oki
Ci] -1-alkyl (C₃~ C_Four) Sodium sulfonate
3- [ω-fluoroalkanoyl (C₆~ C₈) −
N-Ethylamino] -1-propanesulfonic acid sodium salt
N-propyl-N- (2-hydroxyethyl) perm
Fluorooctane sulfonic acid amide, perfluoroal
Kill (C₆~ C_Ten) Sulfonamidopropyltrimethyl
Ammonium salt, perfluoroalkyl (C₆~ C_Ten)
—N-ethylsulfonylglycine salt (K) and the like can be mentioned.
It

As these easily available fluorochemical surfactants, Fluorard (trade name) sold by Sumitomo 3M Ltd., Surflon (trade name) sold by Asahi Glass Co., Ltd., and Dainippon Ink and Chemicals Co., Ltd. are sold. Various grades of Megafac (trade name), Unidyne (trade name) sold by Daikin Industries, Ltd., and Zonir (trade name) sold by DuPont Japan Co., Ltd. can be used.

It is well known that surfactants are classified into four types (anionic, cationic, zwitterionic, nonionic) according to the dissociation state of hydrophilic groups in water. A fluorinated surfactant having the above property can also be used. The content of the fluorosurfactant in the polishing composition is
About 0.01% to about 10% by weight, preferably about 0.
05% to about 5% by weight. If the content of the fluorosurfactant is less than about 0.01% by weight, pits,
Surface defects such as nodules are likely to occur. On the other hand, even if the content of the fluorosurfactant exceeds about 10% by weight,
There is no improvement in the polishing promoting effect due to the increase in the content, and there are disadvantages such as an increase in cost because the fluorosurfactant is expensive.

As the amino acid used in the present invention, either a natural or synthetic amino acid can be used, but preferably the solubility in water (pure water at 25 ° C. 10
An amino acid (hereinafter, referred to as water-soluble amino acid) having a solubility in 0 g of 5 or more. For example, alanine, arginine, glycine, oxyproline, proline, serine, valine and the like can be mentioned. The content of amino acid in the polishing composition is about 1.0% by weight to about 25.0% by weight, preferably about 1.0% by weight to about 15% by weight. When the content of amino acid is less than about 1.0% by weight, the polishing promoting effect of amino acid is not observed. On the other hand, even when the amino acid content exceeds about 25% by weight, no improvement in the polishing-promoting effect due to the increase in the content is observed, and for some amino acids,
It is not completely soluble in water due to its solubility. A polishing composition using these can be obtained with a surface smoothness superior to that of conventional strongly acidic and weakly acidic polishing compositions.

The alumina abrasive used in the present invention is α-alumina, which is obtained by calcining alumina hydrate such as boehmite at about 1100 ° C. to about 1400 ° C. for about 2 to 3 hours, and then dry or wet. The vibration mill, ball mill, attritor, bead mill or the like, or a dry high-speed rotary mill or a known fine pulverizer such as an air flow pulverizer is used for pulverization. If necessary, coarse particles may be classified by a device such as wet gravity settling, centrifugal settling, dry air classification, and the particles may be sized to a desired particle size before use.

The content of the alumina abrasive in the polishing composition is about 1% by weight to about 30% by weight, preferably about 2% by weight to about 25% by weight. The content of alumina abrasive is
When the amount is less than about 1% by weight, the polishing rate decreases, while when the amount exceeds about 30% by weight, the polishing rate is not improved.
There is an inconvenience that the viscosity increases and the workability deteriorates.

The average particle size of the alumina abrasive is about 0.2.
To about 5 μm, preferably about 0.3 to 3 μm. If the average particle size is less than about 0.2 μm, the polishing rate becomes low, and fine particles tend to aggregate to cause defects such as orange peel. If it exceeds about 5 μm, the surface smoothness of the polished surface deteriorates. Causes inconvenience.

If necessary, additives such as a dispersant, an anti-settling agent and an antifoaming agent can be added to the polishing composition of the present invention.

Although the mechanism of action of the present invention is not clear, the fluorine-based surfactant present in the polishing composition improves the wettability of the composition with respect to the polishing surface, so that the composition can be uniformly applied to the polishing surface. At the same time, the water-soluble amino acid present in the composition dissociates to act mechanochemically on the alumina abrasive and polishing debris, thereby improving the lubricity and the like. It is considered that a polishing surface having a higher polishing rate and excellent surface smoothness than the conventional one can be obtained by a synergistic effect with the action. further,
The presence of the water-soluble amino acid can reduce the content of the fluorosurfactant, which is advantageous in terms of cost.

The polishing composition of the present invention is used for precision polishing of metal materials, and is particularly suitable for precision polishing of magnetic disk substrates plated with nickel-based alloys.

[0020]

The polishing composition of the present invention described in detail above is
Among conventional polishing compositions comprising water, an alumina abrasive and a polishing accelerator of a water-soluble metal salt, a fluorine-based surfactant and a water-soluble amino acid are simultaneously added and present instead of the water-soluble metal salt. It has a polishing property equal to or higher than that of the polishing composition, and is capable of performing precision polishing processing to obtain a metal material such as a magnetic disk substrate, a semiconductor substrate, etc., which is particularly excellent in surface smoothness, and fluorine. Compared to the case where only a surfactant is used, the polishing rate can be improved without deteriorating the surface characteristics of the polished surface, and its industrial value is extremely large.

[0021]

EXAMPLES The present invention will be described more specifically below with reference to examples, but the present invention is not limited to these examples.

Embodiment 1 Polishing is a 4-way double-sided polishing machine (plate diameter φ
640 mm) was used for double-sided polishing. The polishing pad is a suede type pad (DOMITEX
25-3) and a 3.5-inch aluminum magnetic disk substrate plated with electroless Ni-P as a workpiece, processing pressure: 100 g / cm ² , lower platen rotation speed;
Polishing was performed under the condition of 40 rpm. As the polishing composition, 8.6% by weight of an alumina abrasive having an average particle diameter of 0.6 μm in pure water and 0.05% of “surflon S-141” sold by Asahi Glass Co., Ltd., which is nonionic as a fluorine-based surfactant. %, Glycine as a water-soluble amino acid was added and suspended at a ratio of 5.0% by weight to prepare a polishing composition slurry, and the slurry was supplied at a rate of 40 ml / min between the disc and the polishing pad. Polishing was performed for 5 minutes.
After polishing, the polishing rate is calculated from the weight reduction of the workpiece, and the surface roughness is determined by the surf coder ET-30H manufactured by Kosaka Laboratory Ltd.
K (measured with a 0.5 μm R stylus stylus, measuring length 0.8 mm, cutoff 80 μm). Moreover, the surface is observed with a differential interference microscope, and scratches, pits,
The presence or absence of surface defects such as nodules was observed. The results are shown in Table 1.

Examples 2 and 3 In the same manner as in Example 1, except that the polishing composition in which the amount of the fluorine-containing surfactant was changed to the following amount was used in the method of Example 1, electroless Ni- A P-plated 3.5 inch aluminum magnetic disk substrate was polished. The results are shown in Table 1.

Examples 4 and 5 In the same manner as in Example 1, except that the amounts of the fluorosurfactant and glycine were changed to those shown below, electroless N was similarly used.
An i-P plated 3.5 inch aluminum magnetic disk substrate was polished. The results are shown in Table 1.

Comparative Examples 1 and 2 In the same manner as in Example 1, except that in the method of Example 1, glycine was not added and only the fluorine-based surfactant was used instead of the amount shown below, 3.5 plated with Ni-P
An inch aluminum magnetic disk substrate was polished. The results are shown in Table 1.

Comparative Examples 3 and 4 In the method of Example 1, aluminum (III) nitrate (Comparative Example 4) and nickel (II) sulfate (Comparative Example 5) were used in place of the fluorosurfactant and the water-soluble amino acid. ) Was added in the same manner as in Example 1 except that the electroless Ni-P plated 3.5 inch aluminum magnetic disk substrate was polished in the same manner as in Example 1. The results are shown in Table 1.

[Types and Addition Amounts (% by Weight) of Polishing Accelerator and Fluorine Surfactant Used in Each Example and Comparative Example] Example 2; Nonionic Fluorine 0.01 Glycine 5.0 Example 3; Nonionic Fluorine-based 0.1 Glycine 5.0 Example 4; Nonionic Fluorine-based 0.1 Glycine 1.0 Example 5; Nonionic Fluorine-based 0.05 Glycine 10.0 Comparative Example 1; Nonionic Fluorine 0.1 Without Glycine Comparative Example 2; Nonionic Fluorine 0.01 Without Glycine Comparative Example 3; Al (NO ₃ ) ₃ 9H ₂ O 1.0 Comparative Example 4; NiSO ₄ 6H ₂ O 1.0

[0028]

[Table 1] * The unit of surface roughness is angstrom, and Ra represents the center line average roughness. In the surface observation column of the table, the expression "no defect" was judged to be inferior in smoothness, etc., to the surface observed by a differential interference microscope, although it had no defects on the polished surface, but was "good". It is something.

Claims (4)

[Claims] 1. A polishing composition for a metal material, which comprises water and an alumina abrasive, wherein the composition contains a fluorine-based surfactant and an amino acid. object. 2. The content of the fluorine-based surfactant is 0.01.
The composition for polishing a metal material according to claim 1, which is 10% by weight to 10% by weight. 3. The content of amino acid is 1.0% by weight to 25.
The composition for polishing a metal material according to claim 1, which is contained in a weight percentage. 4. The content of the alumina abrasive is from 1% by weight to.
The composition for polishing a metal material according to claim 1, which is 30% by weight.