JPH0316998A - Optical part and production thereof - Google Patents

Abstract

PURPOSE:To obtain a molded article of three-dimensional shape having variable film thickness of diamond by making position correlation between a base substrate and a plasma zone relatively variable during formation of diamond film by vapor-phase synthesis. CONSTITUTION:Diamond of any shape is obtained by changing position correlation between a base substrate and a plasma zone by horizontal movement, rotation, vertical movement, inclination, etc., of substrate during formation of diamond film by vapor-phase synthesis such as thermal filament CVD method, microwave plasma CVD method.

Description

DETAILED DESCRIPTION OF THE INVENTION (2) [Field of Industrial Application] The present invention relates to an optical component made of vapor-phase synthetic diamond and a method for manufacturing the same.

[Conventional technology]

The conventional three-dimensional redundant diamond film is published by Nikkei Mechanical, Engineering 988.4. ．． 4. As discussed on pages 50 to 55 of , the hot filament CVD method is used for molding, the base substrate is made of single-piece silicon molded into the required part shape, and the substrate is slowly rotated. At the same time, he was conducting diamond synthesis. Furthermore, heat treatment was performed to remove thermal stress in order to prevent cracks in the diamond film.

[i′1 that the invention attempts to solve! ! [Problem] There is a hot filament CVD method as a conventional technique. However, in order to uniformly shape a complex shaped object, a base substrate must be prepared in advance, and in order to obtain a curved surface like a lens, a difficult-to-cut material such as silicon must be used all the time. Since it must be processed with high precision, it is time consuming and has a high manufacturing cost (3), making it unsuitable for mass production. Furthermore, when attempting to obtain a substrate having a complex shape such as an axisymmetric aspherical surface from one having an axially symmetric uneven surface, the manufacturing cost becomes extremely high.

In addition, as the base substrate becomes more complex, such as a three-dimensional shape, the surface area of the base substrate increases, and after forming the base substrate to a predetermined thickness, the gap between the substrate and the diamond film deposited on the surface of the base substrate by vapor phase deposition increases. thermal stress tends to remain. As a result, the diamond film was cracked or distorted, resulting in a decrease in product yield. Therefore, when the diamond film is elongated to a predetermined thickness, it is necessary to perform heat treatment several times to completely remove the thermal stress, which takes a lot of time and reduces work efficiency. There was a problem.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a diamond manufacturing method that can form a single three-dimensional diamond in any diamond vapor phase synthesis method and improves the yield of the product.

(4) [Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides a method for achieving the above object by relatively controlling the positional relationship between the base substrate and the plasma region during the formation of a diamond film. In this method, the thickness of the diamond film formed on the surface of the substrate can be varied to obtain a three-dimensional shaped body.

[Effect]

The shape or state of a diamond film obtained by hot filament CVD changes depending on the relative position between the base substrate and the plasma region. In other words, on the surface of the substrate placed in the center of the plasma region, the diamond film is more likely to form.
The time required to form a diamond shape increases as the substrate moves away from the center of the plasma region.

In this way, the present invention focuses on the phenomenon of statistical distribution of plasma, and during the formation of a diamond film, the relative position between the base substrate and the plasma region is arbitrarily changed, and the thickness of the diamond film is varied. This is an attempt to obtain a prescriptive form of shape.

When using the above method, the plasma shape or distribution (5) is focused on, so hot filament CVD is
It is also possible to use other vapor phase synthesis methods such as microwave plasma CVD and laser CVD.

Furthermore, a three-dimensional shaped body made of vapor phase synthesized diamond can be obtained at a high yield without performing any molding process on the base substrate, resulting in a significant cost reduction effect.

[Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 2 is a schematic diagram of the diamond manufacturing apparatus of the present invention, and FIG. 2 is an explanatory diagram of the diamond manufacturing method of the present invention.

As shown in FIG.
Methane (CH4) gas and hydrogen (
H2) Flow a gas mixture. After that, when the pressure inside the reaction tube 2 can be set to 5.3 kPa, the magnet 1-
Microwaves oscillated from Ron 3 are introduced, and the thickness of
(6) Plasma 5 is generated around lffI1, silicon-based temporary 4 with a diameter of 25 mm. Then, the mixed gas of methane gas and hydrogen gas is decomposed and diamonds 6 are generated on the surface of the substrate 4.

The substrate 4 was placed on a 30 mm diameter quartz plate 8 supported by an alumina (AQxOs) tube 7 and positioned at the center where the waveguide 9 and the reaction tube 2 intersect. The substrate 4 can be moved in the horizontal direction by a linear motor 10, and can also be rotated by a vacuum step motor.

As shown in the left diagram of FIG. 2A, the center of the substrate 4 is located in the middle of the plasma region 5, and the vacuum step motor
．． When diamond synthesis is performed while rotating at a rotation speed of 2 ppm, a diamond 6 film can be formed on the surface of the center of the substrate 4 as shown in the right figure of Figure A. Next, Figure 2B
As shown in the left figure, the linear motor 10 handles the base 4
Move to the right on the page. Then, rotation diagram B
Diamond 6 glands having the shape shown in the figure on the right can be formed. Further, as shown in the left diagram of FIG. 2C, the substrate is moved to the right, and diamond synthesis is performed in a state where the end of the substrate 4 is located at the center of the plasma region 5. As a result, a diamond 6 film having a concave center can be formed as shown in the right diagram of FIG.

However, the surface of the diamond 6 film thus obtained is uneven. Therefore, in order to put it into practical use as a lens, the surface of the diamond 6 film was smoothed. The smoothing method involves polishing the diamond 6 film until it becomes a mirror surface by sliding it on a pure iron polishing plate heated to 850°C in a hydrogen gas plasma atmosphere. It is coaxial with the axis and has a convex shape.

Finally, by dissolving and removing the substrate 4 with hydrofluoric acid, a lens having a concave surface made of vapor-phase synthetic diamond 6 is completed.

Furthermore, by polishing the back and side surfaces of the diamond 6 film using the above-mentioned smoothing method, the shape accuracy of the lens is improved and it can be easily incorporated into equipment.

As described above, by moving the rotating substrate 4 in the horizontal direction, the positional relationship between the substrate 4 and the plasma region 5 (8) is changed, and the plasma region 4:. Since the film thickness of the diamond 6 is changed, a three-dimensional shaped body can be obtained. Note that these can be put to practical use as optical components such as optical lenses, optical mirrors, and optical windows.

Fig. 3 is a schematic diagram of the diamond manufacturing apparatus of the present invention;
The figure shows an explanatory diagram of the diamond manufacturing method of the present invention.

As shown in FIG. 3, the substrate 4 can be moved up and down by a linear motor 10, and can also be rotated by a normal step motor 12.

As shown in the left diagram of FIG. 4A, the substrate 4 is located within the plasma 5 area.
is located, 0.1ppm by step motor l2
Perform diamond synthesis while rotating at a rotation speed of . As shown in the right figure of Figure A, a diamond 6 film can be formed over the entire surface of the substrate 4. Next, as shown in the left diagram in Figure 4B, when the substrate 4 is moved downward by the linear motor 10, the center becomes convex as shown in the right diagram in Figure 4B (9).The diamond 6 film is shaped. It can be powerful.

Next, mirror polishing is performed using the smoothing method described above.

The rotation axes of the polishing plate and the substrate 4 are arranged coaxially,
The polishing plate has a concave shape.

After polishing, the substrate 4 is dissolved and removed with hydrofluoric acid, and a lens having a convex surface made of vapor-phase synthetic diamond 6 is completed.

FIG. 5 is an explanatory diagram of the diamond manufacturing method of the present invention, and FIG.
The figure shows a cross-sectional view of the diamond 6 film formed on the surface of the substrate 4 by the above method.

As shown in FIG. 5, when the substrate 4 is tilted,
When diamond synthesis is performed by rotating at a rotational speed of p m , a diamond 6 film with a convex center as shown in FIG. 6 can be formed.

FIG. 7 shows a schematic diagram of the diamond manufacturing apparatus of the present invention.

As shown in the figure, the board 4 is moved by the step motor 12.
can be rotated. In addition, a plasma generator consisting of a magnetron 3, a waveguide 9, etc. is connected to a linear motor 10.
By moving the plasma 5 in the vertical direction by (lO), the plasma region 5 can be moved in the vertical direction. That is, in the diamond manufacturing apparatus shown in FIG. 3 mentioned above, the plasma region 5 is fixed and the substrate 4 can move in the vertical direction, whereas here, the plasma region 5 can move in the vertical direction, but the substrate 4 There is a structural difference in that the vertical position of is fixed. but,
The operation is the same, and a diamond 6 film of any shape can be obtained using the diamond manufacturing apparatus shown in FIG.

Naturally, by moving or tilting the plasma generator consisting of the magnetron 3 and waveguide 9 shown in FIG. 7 in the horizontal direction, the plasma region 5 can also be moved in the horizontal direction. It can be tilted.

In this way, by changing the positions of either the substrate 4 or the plasma 5 region, or both the substrate 4 and the plasma 5 region in the diamond 6 shape, it is possible to create a three-dimensional diamond 6 made of gas-phase agai diamond 6. You can obtain the precept form of the shape.

(11) According to this embodiment, a three-dimensional diamond film can be formed using any vapor phase synthesis method.

Further, a base substrate having a complicated shape is not required. Furthermore, since the diamond film does not crack or become distorted, the yield of products can be significantly improved.

〔Effect of the invention〕

As described above, the present invention can greatly contribute to reducing the manufacturing cost and improving the yield of optical products made of vapor phase diamond.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a diamond manufacturing device according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a diamond manufacturing method, and FIG. 3 is a schematic diagram of a diamond manufacturing device according to an embodiment of the present invention.
FIG. 4 is an explanatory diagram of a diamond manufacturing method, FIG. 5 is an explanatory diagram of a diamond manufacturing method according to an embodiment of the present invention, FIG. 6 is a cross-sectional view of a diamond film, and FIG. 7 is an explanatory diagram of a diamond manufacturing method according to an embodiment of the present invention. FIG. 1 is a schematic diagram of a diamond manufacturing device. 4...Substrate, 5...Plasma, 6...Diamond, (12) 10...Linear motor, 1l...Step motor for vacuum, 12...Step motor. Toki 1 Diagram (13) 2nd Kuni Habe 4 2nd Diagram B q 葆2 口〔κ 4th 口Δ 4th Ward 8 Hana Te Kuni No. B Shou No. q Kun

Claims (1)

[Claims] 1. In a method for synthesizing diamond on the surface of a base substrate by flowing a mixed gas of hydrocarbon and hydrogen into an evacuated container and turning it into plasma, the base during diamond formation. 1. A method for manufacturing diamond, which comprises changing the positional relationship between a substrate and a plasma region to obtain a diamond film having an arbitrary shape and polishing the diamond film. 2. A means for synthesizing diamond on the surface of a base substrate by flowing a mixed gas of hydrocarbon and hydrogen into an evacuated container and turning it into plasma, and a method for connecting the base substrate and the plasma region during diamond formation. A diamond manufacturing apparatus comprising means for obtaining a diamond film of an arbitrary shape by varying the positional relationship, and means for polishing the diamond film. 3. The diamond manufacturing method according to claim 1, wherein the substrate is moved in a horizontal direction. 4. The diamond manufacturing method according to claim 1, wherein the substrate is rotated. 5. The diamond manufacturing method according to claim 1, wherein the substrate is moved in a vertical direction. 6. The diamond manufacturing method according to claim 1, wherein the substrate is tilted. 7. A diamond manufacturing method according to claim 1, characterized in that there is relative movement between the plasma region and the substrate. 8. An optical lens manufactured by the diamond manufacturing method according to claim 1. 9. An optical mirror manufactured by the diamond manufacturing method according to claim 1. 10. An optical window manufactured by the diamond manufacturing method according to claim 1.