JPH04331800A - Method of smoothing diamond surface, device therefor and diamond product taking advantage of the same method - Google Patents

Abstract

PURPOSE:To smooth the surface of diamond by irradiating the side of protruded part on the surface of diamond with ion beam and relatively displacing the diamond from the ion beam. CONSTITUTION:Diamond 2 formed by CVD method is fixed to a holding base 3 and an incidence angle theta is adjusted to 60-85 deg. by an incidence angle regulating means so that the side of a protruded part 20a is irradiated with an ion beam 4 while irradiation of a dented part 20b on the surface 20 of the diamond 2 with the ion beam is being avoided. Then the diamond 2 is rotated through the holding base 3, the surface of the diamond is irradiated with the iron beam 4 and the protruded part 20a on the surface of the diamond is removed by sputtering.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for smoothing the surface of diamond used in precision tools, optical parts, etc.

0002

[Prior art] Diamond has excellent hardness, thermal conductivity,
Because it has electrical insulation properties, it is used in cutting tools, scalpels, heat sinks, electronic board materials, etc. Furthermore, since it has excellent light transmittance, it is also used as an optical component. Conventional diamond cutting tools include sintered body cutting tools, single-stone diamond cutting tools, and diamond-coated cutting tools produced by the CVD method.

However, the various tools described above have the following problems. Since the sintered cutting tool uses a bonding material, it has lower wear resistance and thermal conductivity than diamond itself, and is inferior in durability. Furthermore, single-stone diamond cutting tools require large stones, whether natural or artificial, and are therefore expensive. Furthermore, diamond-coated cutting tools made by CVD have a weak adhesion to the cemented carbide substrate, so they may peel off during cutting.

[0004] Therefore, a method of cutting a diamond film formed by vapor phase synthesis into a predetermined shape and fixing it to a cutting tool, and forming a bonding layer, for example, a layer having a component gradient function, between the substrate and the diamond on the surface have been proposed. However, methods of increasing adhesion can be considered. However, diamonds formed by vapor phase synthesis, such as arc discharge plasma jet C
The surface roughness of diamond formed by the VD method is, for example, 50 μmRmax in the maximum height of the convex portion, and for example, 3 μmRmax in the microwave plasma CVD method. Therefore, processing to smoothen the surface, that is, polishing is required. As this polishing method, the so-called "tomo-suri method" using diamond particles is used.

[0005]

Problems to be Solved by the Invention In the conventional diamond polishing method, the polishing rate is 0.1 μm/min. ~0.
Since it is slow at 1 μm/H, it takes a long time to polish small diamonds. Therefore, polishing costs increase and diamond products using this diamond become expensive.

As one means for solving this problem, the present inventor has already invented a diamond polishing method using a laser beam. (Refer to Japanese Patent Application No. 58702 of 1990) According to this method, using a YAG laser, synthetic diamond with a maximum surface convex height Rmax of 50 μm can be made to Rmax of 3 μm in a short time, and can be applied to cutting tools. is possible. However, in order to perform more precise cutting, it is desirable to set the surface roughness of the cutting tool to about 0.6 μmRmax, and an additional step of smoothing the diamond surface is required.

[0007] In view of the above-mentioned circumstances, an object of the present invention is to enable efficient and smooth polishing of diamond. Another object is to obtain a diamond product with high smoothness and low cost.

[0008]

[Means for Solving the Problems] The present invention is characterized in that the diamond and the ion beam are relatively displaced while the ion beam is irradiated toward the side surfaces of the convex portions of the diamond while avoiding the concave portions on the surface of the diamond. After primary polishing is performed by a diamond surface smoothing method, or by bringing the side surface of the laser beam into contact with the diamond surface and moving the side surface relatively along the designed smoothed surface. The above object is achieved by a method for smoothing the surface of a diamond, which comprises displacing the diamond and the ion beam relative to each other while irradiating the ion beam toward the side surfaces of the protrusions while avoiding the concave portions of the surface of the diamond. This is what we are trying to achieve.

[0009]

[Operation] After placing a diamond film synthesized by the CVD method on a diamond support, the ion beam generating means is activated to generate an ion beam. When the ion beam is adjusted to irradiate the sides of the convex portions on the surface of the diamond film using the incident angle adjusting means, the momentum and kinetic energy of the ions reaching the surface of the diamond film cause the surface of the diamond film to irradiate. The protrusions are sputtered, removed and smoothed. Furthermore, by irradiating the diamond surface with this ion beam while relatively shifting the direction of irradiation, the various shaped convex portions on the surface are smoothed out on average, and smoothing progresses effectively. .

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described with reference to the accompanying drawings, in which the same reference numerals have the same names and functions. An ion beam generator is installed on top of the diamond smoothing device A.
For example, ECR (Electron Cyclotron
A resonance (resonance) type ion gun 1 is provided, and a support 3 for a diamond 2 is provided below it. As is well known, the ECR type ion gun 1 utilizes cyclone resonance of electrons in a magnetic field and is an electrodeless discharge. A support stand 3 for the diamond 2 is fixed to a motor 5 in an inclined manner. The motor 5 is provided with an incident angle adjusting means 6. By adjusting this adjusting means 6, the inclination angle of the support base 3 changes, and the intersection angle between the central axis C of the motor 5 and the ion beam 4, that is, the incident angle θ changes. This angle of incidence θ is selected within the range of 60° to 85°, for example. 8 is a vacuum gauge, and 9 is a vacuum pump.

Next, the operation of the embodiment will be explained. CVD
A diamond 2 formed by the method is fixed to a diamond support 2. As shown in FIG. 2, this diamond 2 has an uneven surface 20, that is, a surface to be polished. The incident angle θ is adjusted by the incident angle adjusting means 6 so that the ion beam 4 is irradiated toward the side surface of the convex portion 20a while avoiding the concave portion 20b of the surface 20 of the diamond 2. Then, when the motor 5 is rotated while irradiating the ion beam 4, the support base 3 rotates and the diamond 2 rotates, and the ion beam 4 causes a sputtering phenomenon, and the convex portion 20a on the surface 20 of the diamond is removed. , smoothed.

Next, an experimental example will be explained. Experimental Example 1 A diamond film 2 synthesized by arc discharge plasma jet CVD method was used. This surface is 50μmRmax
It has a roughness of YAG on this surface as shown in Figure 3.
When the side surface 31 of the laser beam of the laser 30 was brought into contact and polished, a roughness of 3 μmRmax was obtained, and this was used as a diamond sample. This diamond sample was fixed to a support base 3 using a silver-based paste, and the diamond surface 20 was irradiated with an ion beam 4 under the following conditions.

[Table 1] Under these conditions, the edges of the crystal grains were slightly rounded, and there was almost no change in surface roughness.

Experimental Example 2 A diamond film 2 synthesized by arc discharge plasma jet CVD method was used as a diamond sample. Therefore, the surface roughness is 50 μmRmax as described above. This diamond sample was fixed to a plate-shaped ceramic heater using a silver-based paste, and this was fixed to a support stand.

[Table 2] In order to create an oxygen atmosphere, oxygen was introduced at a rate of 1 cm3 per minute (standard state). The reason for the oxygen atmosphere is that the smoothing of the diamond surface is accelerated. In addition, the surface of the diamond sample was heated at 40°C using a ceramic heater.
The reason for heating to 0°C is also to speed up smoothing. The reason why smoothing is promoted by creating an oxygen atmosphere or heating the diamond surface is thought to be due to the contribution of chemical reactions to smoothing, but the details have not been confirmed. After 24 hours of ion irradiation, the surface roughness of the diamond sample was 15μmRmax.
smoothed to.

Experimental Examples 3 and 4 A diamond sample was a diamond film 2 with a thickness of about 20 μm synthesized on a silicon substrate (base material) with a thickness of 1 mm by the microwave plasma CVD method. Its surface roughness is 3μ
mRmax. A silicon substrate with a diamond sample synthesized on its surface was fixed to a support using silver-based paste. Note that the same diamond sample and fixing method are used in Example 5, which will be described below.

[Table 3] The difference between Experimental Examples 3 and 4 is that the incident angle is 60° in Experimental Example 3 and 80° in Experimental Example 4. It was found that the diamond surface was smoothed by ion irradiation under these conditions for 3 hours, and in particular, the smoothing progressed more when the incident angle was 80° than when it was 60°. On the diamond surface after irradiation in Experimental Example 4, wrinkle-like lines were formed along the irradiation direction of the ion beam, and the unevenness of the irradiated surface was mainly due to these lines.

Experimental Example 5 Ion irradiation was carried out under the following conditions for the purpose of erasing wrinkle-like lines on the surface of diamond.

[Table 4] When ion irradiation was performed on the surface of the diamond sample for 8 hours under these conditions, the surface roughness increased from 3 μmRmax before irradiation to 0.2 to 0.5 μmRmax, and a smooth surface was obtained. This surface roughness exceeds the value of 0.6 μmRmax required for the precision cutting tool described above. FIG. 4 is a photograph of the diamond surface before irradiation, and FIG. 5 is a photograph after irradiation. The latter has been smoothed, and the wrinkle-like streaks that occurred in the experimental example have disappeared. This is because by rotating the diamond sample for the purpose of changing the irradiation direction of the ion beam, wrinkle-like streaks no longer occur.

In the experimental example, the surface on which diamond smoothing is to be performed, that is, the designed smoothing surface, is entirely covered by the ion beam, but if the designed smoothing surface is wide and the ion beam irradiation misses, the following will occur. It is better to make it . That is, as shown in FIG. 6, the motor 5 is fixed to the support arm 41 via the irradiation angle adjustment means 6, and the arm 41 is attached to the support 40 in the direction indicated by the arrow A40.
The column 40 is provided so as to be movable in the direction indicated by the arrow 4.
Installed so that it can slide in two directions. By reciprocating and rotating the diamond support 3, it is possible to change the irradiation direction of the ion beam 4 with respect to the designed smoothed surface. Further, the irradiation angle adjusting means 6 is controlled by a motor 5.
Instead of providing the ion gun, the ion gun may be rotatably arranged and the irradiation angle of the ion beam may be adjusted. The ion beam generator is not limited to the ECR ion gun, but other devices such as a Kauffman ion gun may be used.

[0017]

As the present invention is constructed as described above, the ion beam collides with the side surface of the convex portion of the diamond, causing a sputtering phenomenon. Therefore, since the protrusions are removed, the surface of the diamond is smoother than in the conventional example. Further, when the surface is polished by a laser beam and then polished by an ion beam, the processing time is shortened and a smoother polished surface can be obtained compared to the conventional example.

[Brief explanation of drawings]

FIG. 1 is a partially sectional front view showing a diamond surface smoothing device according to an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of the main part of FIG. 1;

FIG. 3 is a front view showing laser beam processing.

FIG. 4 is a photograph substituted for a drawing showing the diamond surface before polishing.

FIG. 5 is a photograph substituted for a drawing showing the diamond surface after polishing.

FIG. 6 is a front view of main parts showing another embodiment.

[Explanation of symbols]

1 Ion beam generation means 2 Diamond 3 Diamond support stand 4 Ion beam 5 Motor 6 Incident angle adjustment means θ Incident angle

Claims (10)

[Claims] 1. Smoothing of the surface of a diamond, characterized by displacing the diamond and the ion beam relative to each other while irradiating the ion beam toward the side surfaces of the convex portions while avoiding the concave portions of the surface of the diamond. Method. [Claim 2] After primary polishing is performed by bringing the side surface of the laser beam into contact with the diamond surface and moving the side surface relatively along the designed smoothed surface, the diamond surface is polished while avoiding the concavities. A method for smoothing the surface of a diamond, which comprises displacing the diamond and the ion beam relative to each other while irradiating the ion beam toward the side surfaces of the convex portions. 3. The method for smoothing a diamond surface according to claim 1, wherein the ion beam generating means is an ECR ion gun. 4. The method for smoothing a diamond surface according to claim 1, wherein the ion beam irradiation is performed in an oxygen atmosphere. 5. The method for smoothing a diamond surface according to claim 1, wherein the diamond is heated. [Claim 6] The irradiation angle of the ion beam is 60 to 85°.
The method for smoothing the surface of a diamond according to claim 1, characterized in that: 7. An ion beam generating means; a diamond support having a driving means; an incident angle adjusting means for directing the ion beam to a side surface of a convex portion while avoiding a concave portion on the surface of the diamond on the support; A diamond surface smoothing device comprising: 8. The diamond surface smoothing device according to claim 7, wherein the driving means is a rotating means. 9. The diamond surface smoothing device according to claim 7, wherein the driving means is a reciprocating means. 10. A diamond product, characterized in that the surface of the diamond film formed by a vapor phase synthesis method is smoothed by irradiating an ion beam toward the side surfaces of the convex parts while avoiding the recesses on the surface of the diamond film. .