JPH0559351A - Composition for abrading metallic material - Google Patents

Abstract

PURPOSE:The subject composition containing water, an alumina abrading material, an abrasion-accelerating agent and further a fluorine-based surfactant, useful for precisely abrading magnetic disk substrate materials such as aluminum and nickel alloys, and giving substrates each having excellent surface smoothness, etc. CONSTITUTION:The objective composition containing water, 1-30wt.% of an alumina abrading material (e.g. alpha-alumina), 0.3-10wt.% of a water-soluble metal salt (preferably aluminum nitrate), and 0.05-10wt.% of a fluorine-based surfactant [e.g. a fluoroalkyl (2-20C) carboxylic acid].

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). The present inventors have previously filed a patent application (Japanese Patent Application No. 2-227264) for a composition for polishing a metal material, which comprises water, an alumina abrasive and a polishing accelerator such as chromium nitrate.

However, these polishing compositions are
Although it has the effect of improving the surface smoothness of the polished surface,
The required level is becoming higher and higher, and there is a strong demand for a polishing composition capable of obtaining a polished surface having excellent surface smoothness.

[0007]

In view of the above circumstances, the inventors of the present invention have earnestly studied to obtain a polishing composition for a metal material, which has a small surface roughness and is capable of obtaining a polished surface without surface defects. It was found that a polishing composition satisfying all of the above objects can be obtained when a fluorine-containing surfactant is contained in a polishing composition comprising a conventional water / alumina abrasive / polishing accelerator, The present invention has been completed.

[0008]

The present invention provides a polishing composition for a metal material comprising water, an alumina abrasive and a polishing accelerator, wherein the composition contains a fluorosurfactant. Another object of the present invention is to provide a polishing composition for a metal material.

The present invention will be described in more detail below. The polishing accelerator used in the present invention is a salt of a metal such as aluminum, nickel, cerium, chromium, iron, lanthanum, or neodymium with nitric acid, an inorganic acid such as sulfuric acid, or a partial organic acid, a so-called water-soluble metal salt. ..

Specifically, aluminum nitrate, aluminum sulfate, aluminum chloride, nickel nitrate, nickel sulfate, nickel formate, nickel acetate, cerium nitrate, cerium chloride, iron nitrate, iron sulfate, iron chloride, iron perchlorate, nitric acid Examples include chromium, lanthanum nitrate, neodymium nitrate, ammonium cerium nitrate, formic acid, acetic acid, lactic acid and the like. Among these, aluminum nitrate, nickel sulfate, chromium nitrate, cerium nitrate, ammonium nitrate, in that the composition exerts a mechanochemical polishing action on the polishing surface, that is, the dispersion and aggregation state of the alumina polishing material and polishing debris act favorably. Cerium and lanthanum nitrate are preferred.

The content of the polishing accelerator in the polishing composition is about 0.3 to about 10% by weight, preferably about 0.5 to about 5% by weight. When the content of the polishing accelerator is less than about 0.3% by weight, the polishing rate is lowered and defects such as pits and nodules are likely to occur. On the other hand, even if the content of the polishing accelerator exceeds about 10% by weight, the polishing promoting effect is not improved and the burden of wastewater treatment is increased.

Fluorine-based surface active agent used in the present invention
The agent is a hydrophobic group in the hydrocarbon chain.
, Fully fluorinated fluorocarbon chains
Any surfactant having
Le (C₂~ C₂₀) Carboxylic acid, perfluoroalkyl carbonate
Rubonic acid (C₇~ C₁₃), Perfluoroalkyl (C _Four
~ C₁₂) Carboxylate (Li, K, Na, NH_Four),
-Fluoroalkyl (C_Four~ C₁₂) Sulfonate (L
i, K, Na, NH_Four), Perfluorooctane sulfo
Acid diethanolamide, perfluoroalkyl polio
Xyethylene ethanol, 3- [ω-fluoroalkyl
(C₆~ C₁₁) Oxy] -1-alkyl (C₃~ C_Four)
Sodium sulfonate, 3- [ω-fluoroalkanoy
Le (C₆~ C₈) -N-Ethylamino] -1-propane
Sodium sulfonate, N-propyl-N- (2-hydr
Roxyethyl) perfluorooctane sulfonate
De perfluoroalkyl (C₆~ C_Ten) Sulfonami
Dopropyl trimethyl ammonium salt, perfluoroa
Rukiru (C₆~ C_Ten) -N-Ethylsulfonylglycine
Salt (K) etc. are mentioned.

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

As is well known, 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 0.05% by weight to about 10% by weight, preferably about 0.1% by weight to about 5% by weight. When the content of the fluorosurfactant is less than about 0.05% by weight,
Almost no effect of improving surface smoothness is seen. On the other hand, even if the content of the fluorosurfactant exceeds about 10% by weight, no improvement in the polishing promoting effect due to the increased content is seen, and the cost of the fluorosurfactant is high because it is expensive. And other inconveniences occur.

The alumina abrasive used in the present invention is α-alumina, which is obtained by calcining alumina hydrate such as boehmite at 1100 ° C. to 1400 ° C. for 2 to 3 hours, and then using a dry or wet vibration mill. A ball mill, an attritor, a bead mill, etc., or a known high-speed rotary mill or a known fine pulverizer such as a gas stream 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 will be low, and fine particles will easily aggregate to cause defects such as orange peel, and if it exceeds about 5 μm, the surface smoothness of the polished surface will deteriorate. It 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, in the conventional polishing composition, the mechanochemical polishing action of the polishing accelerator, that is, the action by controlling the dispersion and aggregation state of the alumina abrasive and polishing debris. Although it was only, by the presence of a fluorine-based surfactant in the composition, to improve the wettability of the composition to the polishing surface, it acts uniformly on the polishing surface by the synergistic effect of it and the above action, It is presumed that a polished surface having a surface smoothness superior to the conventional one can be obtained.

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

[0021]

The polishing composition of the present invention described in detail above is
A magnetic disk substrate or a semiconductor substrate having a surface smoothness superior to conventional ones by adding a fluorine-containing surfactant to a conventional polishing composition comprising water, an alumina abrasive and a water-soluble metal salt polishing accelerator. It is possible to perform precision polishing processing to obtain metal materials such as, and its industrial value is enormous.

[Examples] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 4-way double-side polishing machine for polishing (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.

The polishing composition has a mean particle size of 0.6 in pure water.
alumina abrasive 8.6 wt% of [mu] m, as a polishing accelerator, aluminum nitrate _{[Al (NO 3) 3 · 9H} 2 O ]
1.0% by weight, nonionic as a fluorosurfactant, "surflon S-141" sold by Asahi Glass Co., Ltd., was added and suspended at a ratio of 1.0% by weight to prepare a polishing composition slurry, Slurry supply rate: 40 ml / min
Polishing was carried out for 5 minutes while being supplied between the disc and the polishing pad.

After polishing, the polishing rate was calculated from the weight reduction of the work piece, and the surface roughness was measured using a surfcoder ET-30HK (0.5 μmR stylus stylus manufactured by Kosaka Laboratory Ltd.) to measure a length of 0.8 mm. , Cutoff 80 μm). Further, the surface was observed with a differential interference microscope to observe the presence of surface defects such as scratches, pits and nodules. The results are shown in Table 1.

Examples 2 to 5 Electroless Ni-P plating was performed in the same manner as in Example 1 except that the polishing composition in which the polishing accelerator was changed to the type shown below was used in the method of Example 1. The 3.5 inch aluminum magnetic disk substrate was polished. The results are shown in Table 1.

Example 6 In the same manner as in Example 1, except that the amount of the fluorine-based surfactant added was changed to the following, the same electroless Ni-P plated 3.5 inch aluminum was used. The magnetic disk substrate was polished. The results are shown in Table 1.

Comparative Examples 1 to 5 In the same manner as in Example 1, except that the fluorine-type surfactant was not added and only the polishing accelerator was used instead of the types shown below in the method of Example 1. 3.5 with electrolytic Ni-P plating
An inch aluminum magnetic disk substrate was polished. The results are shown in Table 1.

Comparative Example 6 In the same manner as in Example 1, except that the polishing accelerator was not added and only the fluorine-based surfactant was used in the method of Example 1.
A 3.5-inch aluminum magnetic disk substrate plated with electroless Ni-P was polished. The results are shown in Table 1.
Shown in.

[Types and Addition Amounts (% by Weight) of Polishing Accelerator and Fluorine Surfactant Used in Each Example and Comparative Example] Example 2; NiSO ₄ .6H ₂ O 1.0 nonionic fluorine type 1.0 example _{3; Cr (NO 3) 3} · 9H 2 O 1.0 nonionic fluorine-based 1.0 example _{4; Ce (NO 3) 3} · 6H 2 O 1.0 nonionic fluorine-based 1.0 example _{5; La (NO 3) 3} · 6H 2 O 1.0 nonionic fluorine-based 1.0 example _{6; Al (NO 3) 3} · 9H 2 O 1.0 nonionic fluorine-based 0.1 Comparative example _{1; Al (NO 3) 3} · 9H 2 O 1.0 nonionic fluorine-based 0 Comparative example _{2; NiSO 4 · 6H 2 O} 1.0 nonionic fluorine-based 0 Comparative example 3 Cr ( _{NO 3) 3 · 9H 2 O} 1.0 nonionic fluorine-based 0 Comparative example _{4; Ce (NO 3) 3} · 6H 2 O 1.0 nonionic fluorine-based 0 Comparative example 5; La (NO _{3) 3} 6H ₂ O 1.0 Nonionic Fluorine-based 0 Comparative Example 6; None Nonionic Fluorine-based 0 .1

[0031]

[Table 1] * The unit of surface roughness is angstrom, Ra is the center line average roughness, and Rmax is the maximum height. In addition, the expression "no defect" in the surface observation column in the table means that "there is no defect on the polished surface,"
It is judged that the smoothness is inferior to that described as “good”.

Claims (4)

[Claims] 1. A polishing composition for a metal material containing water, an alumina abrasive, and a water-soluble metal salt as a polishing accelerator, wherein the composition contains a fluorine-based surfactant. A polishing composition for a metal material. 2. The content of the fluorosurfactant is 0.05.
The composition for polishing a metal material according to claim 1, which is 10% by weight to 10% by weight. 3. The polishing composition for a metal material according to claim 1, wherein the content of the water-soluble metal salt as a polishing accelerator is 0.3% by weight to 10% by weight. 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.