JPH04354676A - Grinding wheel for precision machining - Google Patents

Abstract

PURPOSE:To provide a grindstone capable of finishing mainly a ceramic sintered body, a hard material such as glass or mono-crystal or a soft work material into a mirror surface with excellent surface roughness. CONSTITUTION:A resin bond grindstone for precision machining containing at least 30 vol.% of abrasive grains of a nonstoichiometric compound made of at least one of metal oxide, metal oxide/carbide, metal oxide/nitride and a mutual solid solution of them is provided. The surface roughness of a work material is improved by about 8.5-66 times as compared with a conventional grinding wheel containing abrasive grains of a stoichiometric compound.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention applies to ceramics and glass used in various industries such as semiconductor wafers and substrates, magnetic head substrates, laser reflectors, optical parts, precision mechanical parts, precision measuring instrument parts, and electronic parts. This invention relates to a precision machining grindstone that is ideal for mirror-finishing hard materials such as single crystals or soft processed materials.

0002

[Prior Art] Conventionally, in grinding processing or grinding processing, finishing processing for the purpose of mirror finishing such as lapping and polishing has been performed using ultra-hard materials such as diamond or cubic boron nitride, which are harder than the workpiece material. Abrasive grains or a whetstone containing them are used.

On the other hand, there is a finishing method that uses abrasive grains that are softer than the material to be processed, or a grindstone containing them, to produce a chemical reaction induced by mechanical action with the material to be processed, so-called mechanochemical. is proposed.

[0004] A typical example of this mechanochemical processing method is "Mechanoche" by Vora et al.
Mical Polishing of Sil
iconNitride” [J. Am. Cer. Soc.
, 65 (9) C-140 (1982)], Karaki et al.
``Processing speed acceleration mechanism in mechanochemical polishing of single crystals'' [Precision Machinery, 46, 3 (1980) 53-5
9], Ochiai et al., “Mechanochemical polishing of ferrite materials” [Journal of Japan Society for Precision Engineering, 54, 3 (1988) 146-
151] and Japanese Unexamined Patent Publication No. 64-64766.

[0005]

[Problem to be solved by the invention] “Mec” by Vora et al.
Hanochemical Polishing
ofSilicon Nitride” uses silicon nitride and ceramics such as CaCO3, MgO, SiO2,
It has been described that wet mechanochemical polishing was performed using soft abrasive grains such as Fe2O3 and Fe3O4, and Karaki et al. Mechanochemical polishing with ZrO2 abrasive grains in an alkaline solution is described. Ochiai et al.'s ``mechanochemical polishing of ferrite materials'' uses Mn-Zn.
It is described that single-crystal ferrite was mechanochemically polished with Al2O3 abrasive grains in distilled water, sodium hydroxide, and hydrochloric acid solutions.

Furthermore, Japanese Patent Application Laid-Open No. 64-64766 discloses abrasive grains of metals, oxides, nitrides, silicides, borides, and carbides that have excellent reactivity with the workpiece material, and abrasive grains of polyacetal, polyethylene, A grindstone material made of acrylonitrile, polyphenyl sulfide, phenol, and epoxy resin molded to be softer than the material to be processed is described.

Among the above, the former by Vora, Karaki, and Ochiai et al. performed mechanochemical polishing using oxide abrasive grains, and the latter, Japanese Patent Application Laid-Open No. 64-64766, uses oxides, especially A grindstone made of oxide abrasive grains of Cr2O3, Fe2O3, and CeO2 and a resin is described. The abrasive grains used in these products are commercially available and consist of chemically stable stoichiometric compounds, so the polishing effect is weak, and attempts are made to increase the polishing effect by intervening a solvent. When the surface of the material to be processed is made into a mirror surface, there is a problem in that it is necessary to process the material for a long time and that the mirror surface state after processing, that is, the surface roughness is not satisfactory.

The present invention solves the above-mentioned problems. Specifically, the abrasive grains of a chemically metastable non-stoichiometric compound are solidified with a resin to form a coating with a high polishing effect. The object of the present invention is to provide a grindstone for precision machining that can improve the surface roughness of processed materials.

[0009]

[Means for Solving the Problems] The present inventors have proposed a method for reducing the processing time and improving the surface accuracy of the workpiece by mirror-finishing the surface of the workpiece material such as a semiconductor Si wafer or a ceramic sintered body. We were considering that mirror polishing could be achieved by mechanochemical polishing using a grindstone made of metal oxide hardened with resin, which is softer than ultra-hard abrasive grains. By using a treated metal oxide consisting of a non-stoichiometric compound, a sufficient mechanochemical polishing effect can be achieved even in a dry method, instead of the conventional wet mechanochemical polishing using an acidic or alkaline solution. knowledge that the abrasive grains of non-stoichiometric compounds promote oxidation of the surface of the workpiece material through a catalytic action based on oxygen defects, and that this effect can significantly improve the surface precision of the workpiece material. I got it.

The present invention was completed based on the above findings.

That is, the precision machining grindstone of the present invention is a resin bonded grindstone, and the grindstone is coated with a non-chemical compound made of at least one of metal oxides, oxycarbides, oxynitrides, and mutual solid solutions thereof. At least 3 stoichiometric compound abrasive grains
It is characterized by containing 0% by volume.

[0012] In the present invention, the abrasive grains of non-stoichiometric compounds refer to particles 2a, 3a, 4a, 5a, 6a, and 7a of the periodic table.
, 8a, 3b, 4b, 5b, and particles of at least one non-stoichiometric compound among oxides, oxycarbides, oxynitrides and mutual solid solutions of these; If the metal element is represented by M and the non-metal element is represented by A, then
(M1A1-W), (M1A2-X), (M2A3-Y
), (M3A4-Z), (stoichiometric compounds are M1A1, M1A2, M2A3, M3A4
It becomes. ) To give a specific example, in the case of chromium oxide, C
rO2-X, C2O3-Y, in the case of iron oxide, FeO1-
In the case of W, Fe2O3-Y, Fe3O4-Z, and titanium oxide, TiO1-W, TiO2-X, and Ti2O3-Y can be mentioned. (However, M and A represent the atomic ratio.) Abrasive grains of non-stoichiometric compounds include rare earth elements, oxides, oxycarbides, oxynitrides of 4a, 6a, 8a of the periodic table, and their mutual It is preferable that it is made of at least one kind of solid solution, and among these, at least one kind of oxide, oxycarbide, oxynitride, and mutual solid solution of titanium, chromium, or iron, specifically, for example, CrO2-X
, TiO2-X (however, 0.77>x>0), Cr2
It is preferable to use O3-Y, Fe2O3-Y (0.6>y0) because the surface accuracy of the workpiece material is particularly improved.

Furthermore, it is preferable that 0.06>x>0
．． 03,0.6>y>0.11.

The finer the abrasive grains of a non-stoichiometric compound, the higher the activation, the more remarkable the improvement in the surface precision of the workpiece material, and the standard deviation of the particle size distribution when the average grain size is 1.0 μm or less. Abrasive grains consisting of uniform particles, particularly preferably an average particle size of 0.
The particles are 0.05 μm or less. If the content of the abrasive grains is less than 30% by volume, the effect of improving the surface accuracy of the workpiece material will be significantly reduced.

In particular, the precision machining grindstone of the present invention has 30 to 80 volumes of abrasive grains of the above-mentioned non-stoichiometric compound and 1 volume of resin.
From the viewpoint of the strength of the grindstone, it is preferable that the amount is 5 to 49% by volume and the remainder is other substances mainly composed of metal compounds.

The resin used in the present invention is not particularly limited, but when it is made of phenol, epoxy, polyimide, polystyrene, or polyethylene, the moldability and strength of the grindstone and the abrasive grains and other substances during molding of the grindstone may be affected. This is preferable because it has excellent dispersibility.

[0017] In the present invention, the other substances mainly composed of metal compounds are not particularly limited as long as they have been conventionally used in grindstones, and specifically include ultra-hard abrasive grains, chemical Examples include abrasive grains, glass, whiskers, fibers, carbon, and more specifically,
For example, Al2O3, SiO2, SiC, Fe2O3, Z
rO2, CeO2, CBN, WBN, (wurtzite BN
) and diamonds.

The precision machining whetstone of the present invention can be produced by a conventional grindstone forming method, specifically, by mixing abrasive grains and a starting material containing a resin or other substances as necessary, sieving, and then sieving. ,
It can be produced by hot pressing with a mold.

[0019]

[Function] When the precision machining grindstone of the present invention is used, the abrasive grains of the non-stoichiometric compound further increase activation due to the inherent activation force and the frictional heat on the surface of the workpiece material. This significantly promotes the chemical reaction between the grains and the material to be processed, the so-called mechanochemical action. In addition, the resin contained in the whetstone has the effect of holding the abrasive grains of the non-stoichiometric compound and other substances, increasing the strength of the whetstone, and when in use, the abrasive grains of the non-stoichiometric compound and the workpiece material. It has the effect of making it easier to come into contact with the surface.

[0020]

[Example 1] Starting raw materials made into non-stoichiometric compound abrasive grains by reducing various commercially available abrasive grains with an average particle size of 1 μm or less, and various metals or semimetals with an average particle size of 1 μm or less Each sample was obtained by blending the compound powder and various resins as shown in Table 1.

[0021] Each sample having the compounding composition shown in Table 1 was mixed and sieved using a grinder, and then grindstones were prepared under the sintering conditions shown in Table 2.

[0022]

[Table 1]

[0023]

[Table 2] Using products 1 to 15 of the present invention obtained from Table 2, comparative products 1 to 5, and a commercially available silica sol as comparative product 6, mirror polishing was attempted under the following conditions. Mirror polishing finishing conditions Work material: Ceramics, glass, and Si shown in Table 3
The surface of the wafer was polished with a 1 μm diamond grindstone, rotation speed: 90 rpm, processing pressure: 120 g/cm2, polishing method: dry evaluation: the surface roughness of the workpiece material at a given polishing time, the roughness of the workpiece material after 60 minutes of polishing. Observation of surface condition and damage condition of whetstone.

Table 3 shows the results of the mirror polishing test.

[0025]

[Table 3]

[0026]

Example 2 Commercially available Cr2O3 having an average particle diameter of 0.1 μm and a uniform standard deviation was subjected to reduction treatment under various conditions to obtain various types of Cr2O3-y abrasive grains.

After blending the Cr2O3-y abrasive grains and phenol resin as shown in Table 4, various types of grindstones were prepared in the same manner as in Example 1.

[0028]

[Table 4] Using the various grindstones shown in Table 4, a mirror polishing finish test similar to that in Example 1 was conducted, and the results are shown in Table 5.

Of the Cr2O3-y used here, Cr2
The hardness of O2.4 abrasive grains was measured and the results are shown in FIG.

[0030]

[Table 5]

[0031]

Effects of the Invention: The precision machining whetstone of the present invention uses the abrasive grains of a non-stoichiometric compound contained in the whetstone and the frictional heat generated on the surface of the workpiece material during use. This grindstone is highly effective in accelerating oxidation reactions by repeatedly oxidizing, forming an oxide film, and removing that film on the sub-nanometer order on the surface of the surface. The surface roughness of the workpiece material (
This has a remarkable effect of improving Rmax) by about 8.5 to 66 times.

[Brief explanation of the drawing]

[Figure 1] One of the abrasive grains used in the precision processing grindstone of the present invention
It is a graph showing the relationship between temperature and hardness of Cr2O2.4 which is a seed.

Claims (6)

[Claims] 1. A resin-bonded grindstone, the grindstone comprising at least 30 abrasive grains of a non-stoichiometric compound consisting of at least one of metal oxides, oxycarbides, oxynitrides, and mutual solid solutions thereof. A grindstone for precision machining characterized by containing % by volume. Claim 2: A claim characterized in that the abrasive grains of the non-stoichiometric compound are made of at least one of titanium, chromium, or iron oxides, oxycarbides, oxynitrides, and mutual solid solutions thereof. A grindstone for precision processing according to item 1. 3. The precision machining whetstone according to claim 1, wherein the abrasive grains of the non-stoichiometric compound are particles with an average grain size of 1.0 μm or less. 4. A resin-bonded grindstone, which contains 15 to 49% by volume of resin and at least one of metal oxides, oxycarbides, oxynitrides, and mutual solid solutions thereof.
Abrasive grains of non-stoichiometric compounds consisting of seeds are 30-80% by volume
A grindstone for precision machining, characterized in that the remainder is composed of other substances whose main component is a metal compound. 5. A claim characterized in that the resin is made of phenol, epoxy, polyimide, polystyrene or polyethylene, and the abrasive grains of the non-stoichiometric compound are made of titanium, chromium and/or iron oxide. 4. The precision processing grindstone described in 4. 6. The precision machining grindstone according to claim 4, wherein the abrasive grains of the non-stoichiometric compound are powders with an average particle size of 1.0 μm or less.