JPS63114865A - Ultra-precise polishing abrasive material - Google Patents

Abstract

PURPOSE:To make it possible to rapidly obtain a polished surface with no scratches, by forming an ultra-precise polishing abrasive material from spherical ultramicro particle-like beta type polycrystal silicon carbide having an averaged particle size of 0.01 to 1 mum, which is the aggregate of heat-treated beta type silicon carbide. CONSTITUTION:An ultra-precise polishing abrasive material is formed of spherical ultramicro particle-like beta type polycrystal silicon carbide having an averaged particle size of 0.01 to 1 mum, which is the aggregate of heat-treated beta type silicon carbide. In this case, it is preferable that the crystallite normally has greater than about 50 angstroms. Such ultramicro particle-like beta type silicon carbide is obtained from organic silicon carbide in which at least one identicalsSiH bond exists in one molecule but no SiX (X is halogen atoms or oxygen atom) bond exists, such as a methyl hydrogen silane compound, which is subjected to a vapor phase cracking process at a temperature of about 750 deg. C, and is then heat-treated at the temperature of 1,000 to 2,000 deg. C. Thus, it is possible to rapidly obtain an excellent polished surface with no scratches.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an abrasive material for ultra-precision polishing made of spherical ultrafine silicon carbide particles. The present invention relates to an abrasive material for ultra-precision polishing that provides high polishing speed and high polishing speed.

In general, in order to obtain a polished product with high processing quality during polishing, it is necessary to find processing conditions that have excellent surface accuracy and have no damaged layer. This requires optimizing conditions such as the abrasive material, polisher, polishing liquid, polisher movement speed, pressure, etc. in order to reduce the mechanical action of the abrasive material. For example, in order to obtain a precision-machined surface, it is effective to use a soft material such as polyurethane artificial leather for the polisher to elastically hold the abrasive material, but precision machining with excellent machining quality is effective. The selection of abrasive material is most important in terms of obtaining good quality.

Conventionally, optical glass, semiconductor substrates such as silicon wafers,
When performing ultra-precision polishing of metal materials and plastics such as magnetic disk substrates, magnetic heads, and molds, fine powders such as silicon carbide, aluminum oxide, zirconium oxide, cerium oxide, and silicon dioxide are usually used as the polishing material. These fine powders are manufactured by, for example, pulverizing silicon carbide, fused alumina, calcined alumina, etc. by the Acheson method.

However, silicon carbide of the Acheson method as described above,
Pulverized products such as fused alumina and calcined alumina have non-uniform shapes such as acute angles, needles, and plates, and when ultra-precision polishing is performed using particles with such shapes as an abrasive, Scratches are generated on the surface of the object to be polished, making it impossible to obtain a good polished surface, resulting in a problem of poor precision.

For this reason, as an abrasive for ultra-precision polishing that provides an excellent polishing surface with no scratches, it is preferable to use one with a spherical particle shape, especially one with a fine particle diameter and a spherical shape.
There is a need for something that also has sufficient hardness.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an abrasive material for ultra-precision polishing that has a high polishing rate and can provide an excellent polished surface without scratches.

As a result of various studies to achieve the above object, the inventors of the present invention have developed an aggregate of heat-treated β-type silicon carbide with an average particle size of 0.01 to 1. Ultrafine particle β with spherical shape of voice
When polycrystalline silicon carbide is used as an abrasive for ultra-precision polishing, it provides an excellent polishing surface without creating scratches on the surface of the object being polished, and its spherical shape allows the polishing pressure to be applied uniformly to the object being polished. It has been found that the polishing effect increases significantly, the polishing rate becomes extremely high, the ultrafine particles become finer during the polishing process, and a high-quality workpiece is obtained.

That is, the present inventors have studied various ways to obtain spherical and highly pure silicon carbide in the form of fine powder without going through a pulverization process, and first, the molecule contains at least one SiH bond, However, 75
It has been discovered that by carrying out gas phase pyrolysis at temperatures above 0"C, it is possible to obtain spherical, highly pure fine silicon carbide powder in good yield without any post-treatment such as a pulverization process (Japanese Patent Publication No. 61-56
No. 46, JP-A-60-46911, JP-A-60-'4
No. 6912) conducted further research on the properties of the fine powder obtained by this method and its manufacturing conditions, and when observing and measuring this fine powder silicon carbide with an electron microscope, it was found that it was different from commercially available products made by conventional manufacturing methods. It has a different, almost perfectly spherical shape, and the dark-field image obtained by β-31C (1,1,1) diffraction shows that it is an aggregate of β-type silicon carbide crystallites with individual particles of less than 50 Å. , whose average particle size is 0.01
It was confirmed that it was ~1p. Furthermore, this ultrafine particulate silicon carbide is treated with, for example, Ar.

In an inert gas atmosphere such as He, Ne, Xe, etc. and/or H
2, 1000-20 in a non-oxidizing gas atmosphere such as N2
By processing at a temperature of 00°C, it is possible to increase the crystallite size to 50 Å or more while keeping the particle shape spherical, and even after this heat treatment, the average particle size of this aggregate remains the same as that of the heat treatment. In addition to confirming that it is approximately the same as before, 0.01 to 1 p, we also found that when this spherical ultrafine particle silicon carbide powder bed is used as an abrasive, the polishing speed is significantly higher than that of conventional abrasives. It has been found that the average particle diameter is 0.00000000000000000000000000000000000000000000000000000000000000000 is large.
The inventors have discovered that spherical ultrafine particle β-type polycrystalline silicon carbide, which has a pitch of 01 to 1, is very effective as an abrasive for ultraprecision polishing, and has thus arrived at the present invention.

The present invention will be explained in more detail below.

The abrasive material for ultra-precision polishing of the present invention is an aggregate of heat-treated β-type silicon carbide, and has an average particle size of 0.01 to 1 μm and a spherical shape. It is made of crystalline silicon carbide, and those with a crystallite size larger than 50 are usually preferably used.

The ultrafine particulate β-type silicon carbide of the present invention is, for example, an organosilicon compound having at least one ioSiH bond in the molecule and containing no 5iX (X represents a halogen atom or an oxygen atom) bond. It can be obtained by heat-treating the product subjected to gas-phase pyrolysis at temperatures above °C.

In this case, the organic silicon compound has the general formula (CH,)a 5ibHe (where b=an integer of 1 to 3, 2b+1≧a, a≧b, 2b+1≧C2C≧1.a+
Methylhydrodiene silane compounds represented by c=2b+2) are preferably used, and at least one of these methylhydrodiene silane compounds is heated for 30 min in the presence of a carrier gas such as hydrogen, nitrogen, helium, or argon.
Preferably, the gas phase pyrolysis is carried out in a reaction zone at 750-1600° C. at a concentration of less than vol. %.

In addition, when heat-treating silicon carbide obtained by vapor phase pyrolysis in this way, the heat treatment temperature is 1000-2000
The temperature is preferably 00°C.

At temperatures lower than 1000° C., there is almost no growth in the crystallite size of the silicon carbide, and at temperatures higher than 2000° C., changes in shape may occur as the particles grow.

Note that since the methylhydrodienesilane compound as the starting material can be easily purified in advance by rectification, the resulting ultrafine particulate β-type silicon carbide can also be obtained with extremely high purity. In addition, the thickness and spherical shape of the silicon carbide crystallites obtained, the average particle size of the aggregate powder, the concentration of the methylhydrodienesilane compound in the reaction zone, the residence time, the gas linear velocity, the reaction temperature, These conditions can be freely adjusted by selecting the reaction conditions such as the type of carrier gas and the heat treatment conditions such as the treatment temperature, treatment time, and type of atmospheric gas in the heat treatment. Just set it.

The abrasive of the present invention is an aggregate of β-type silicon carbide that has been heat-treated as described above, and has an average particle size of 0.01 to IIi.
! n and whose shape is spherical, ultrafine particle β-type polycrystalline silicon carbide, especially one with a crystallite size larger than 50, more preferably the general formula (CH,)aSibH
c (here, b=1~3゜2b+1≧a, a>
b p 2 b + l≧c)4. a+c=2b+2) is vapor-phase pyrolyzed in a reaction zone at 750 to 1600°C, and the resulting amorphous silicon carbide fine powder is pyrolyzed at 1000 to 2000°C. Silicon carbide obtained by heat treatment at a temperature with an average particle size of 0
．． The abrasive material of the present invention can be used for optical glass, semiconductor substrates such as silicon wafers, magnetic disk substrates, magnetic heads, gold, etc. Suitable for ultra-precision polishing of metal materials such as molds and plastics. In addition, the polishing conditions when using the abrasive material of the present invention can be the precision polishing conditions commonly used in the past, and a known precision polishing machine can be used as the polishing machine, but the conditions of use are not particularly limited. It's not something you can do.

According to the abrasive material according to the present invention, when it is used for ultra-precision polishing of metals such as silicon wafers, stainless steel, mold steel, cast iron, steel, copper, aluminum, and brass, it does not cause scratches on the surface of the polished object. The spherical shape allows the polishing pressure to be applied uniformly to the object to be polished, significantly increasing the polishing effect, increasing the polishing speed, and eliminating ultrafine particles during the polishing process. This progresses in the miniaturization of the materials and allows for the production of high-quality workpieces.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples.

[Example 1] An alumina reaction tube with an inner diameter of 52 mm and a length of 1000 m+ was installed in a horizontal reactor, and the temperature at the center was set to 1450°C.
I kept it. Tetramethyldisilane (H(
CH-)2 SiS l (CHa)z H) 4
When hydrogen gas containing a concentration of 10% by volume was introduced at a rate of 1200mM/min for 4 hours to carry out vapor phase thermal decomposition of tetramethyldisilane, a brown silicon carbide fine powder of 27.
9 g (yield 82%) was obtained.

Furthermore, the obtained silicon carbide fine powder was transferred onto an alumina boat, and then placed in a box-type electric furnace with an internal volume of 6000 ci, the interior was sufficiently replaced with Ar gas, and the furnace was heated in an Ar gas atmosphere. Heat treatment was performed at a temperature of 16oO<0>C for a treatment time of 3 hours.

From the observation results of the obtained silicon carbide ultrafine particles using X-ray diffraction, electron beam diffraction, and transmission electron microscopy, it was found that this silicon carbide fine powder has β-type carbonization with more than 50 crystallites, as shown in Table 1. An aggregate of silicon with an average particle size of 0.0
It was confirmed that the particles were ultrafine silicon carbide particles with a spherical shape in the range of 1 to 1p.

Using the above ultrafine silicon carbide, silicon wafers, stainless steel (SUS 304), mold steel (18%
The polishing properties for Ni maraging steel (Ni maraging steel) were investigated.

The object to be polished was 5ic (GC: #600), AQ, O.

(WA# 1200), AM, 03 (WA# 4000)
(7) Preliminary polishing is performed in this order, and then a disc rotary polisher is used, and polyurethane artificial leather with an outer diameter of 180 nm is used as the polisher, rotation speed is 50 rpm, and pressure is 55 g/d.
Polishing was carried out for 3 hours under the following conditions, while a slurry prepared by suspending an abrasive material (the above-mentioned ultrafine particulate silicon carbide) at a concentration of 10% in water having a pH of 7 was fed at a rate of 5 d/min. Table 1 shows the results of the polishing properties for the objects to be polished.

Table 1 From the results shown in Table 1, silicon wafers, SUS 30
By polishing 4.18%Ni maraging steel, there are no scratches on the polished surfaces of these polished objects.
It was found that not only an excellent polished surface was obtained, but also a high polishing rate for each object to be polished.

[Examples 2 to 7] Various polished objects were prepared in the same manner as in Example 1 using ultrafine silicon carbide produced in the same manner as in Example 1 as the abrasive material except for the heat treatment conditions shown in Table 2. The object was polished and the results shown in Table 2 were obtained.

From the results shown in Table 2, the polishing materials of the present invention can provide an excellent polished surface without causing scratches on the surface of the object to be polished, and can polish the object with high precision no matter which one is used. It was also found that the polishing rate was also high.

[Comparative Example 1] Silicon carbide fine powder synthesized in the same manner as in Example 1 was used without heat treatment, and in the same manner as in Example 1, it was applied to silicon wafers, 5US304, 18% Ni maraging steel, etc. When the polished product was polished, the results shown in Table 3 were obtained.

Table 3 From the results shown in Table 3, it was found that ultrafine silicon carbide powder with a small crystallite size without heat treatment provides a good polished surface without scratches, but the polishing rate is slightly inferior. Ta.

[Comparative Examples 2 to 6] Silicon wafers and SUS 304.18% Ni multilayers were prepared in the same manner as in Example 1, except that the abrasives shown in Table 4 were used in place of the ultrafine silicon carbide shown in Example 1. Polished aged steel. The results are shown in Table 4.

From the results shown in Table 4, when an object to be polished is polished using an abrasive material other than the present invention, scratches occur on the surface of the object to be polished, a high-quality polished surface cannot be obtained, and the polishing speed is also slow. It was found that the efficiency was also poor.

Claims (1)

[Scope of Claims] 1. Ultrafine particle β-type polycrystalline silicon carbide which is an aggregate of heat-treated β-type silicon carbide and has an average particle size of 0.01 to 1 μm and a spherical shape. An abrasive material for ultra-precision polishing that is characterized by being made of raw material. 2. Claim 1, wherein the ultrafine β-type polycrystalline silicon carbide is obtained by heat-treating silicon carbide obtained by a gas phase thermal decomposition reaction of a methylhydrodiene silane compound at a temperature of 1000 to 2000°C. Abrasive material for ultra-precision polishing as described.