JP2002098818A - Reflecting mirror member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflecting mirror member coated with a high-quality silicon carbide film having excellent surface smoothness which can be stably manufactured with good reproducibility. SOLUTION: In the reflecting mirror member manufactured by applying a silicon carbide film consisting of silicon carbide on the surface of a specified substrate, the silicon carbide film consists of a crystalline oriented film based on X-ray diffraction and the maximum inclination angle of the growing direction of the crystal from the perpendicular direction to the substrate surface is <=30 deg..

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reflecting mirror member requiring surface smoothness.

[0002]

2. Description of the Related Art Various applications of ceramics have been promoted due to their excellent properties such as high strength and wear resistance. Among them, ceramics are synthesized by a vapor phase synthesis method such as a chemical vapor deposition method or a physical vapor deposition method. 2. Description of the Related Art A reflecting mirror member which is coated on a predetermined substrate by a phase growth method or the like and has a ceramic surface characteristic is known.

For example, a silicon carbide film formed by a chemical vapor deposition method has a dense, void-free and ultra-smooth surface having high smoothness. Although the surface roughness depends on the surface shape, it has been reported that a smooth surface can be obtained in the order of an aspheric surface, a spherical surface, and a plane, and an aspheric surface can have a surface roughness of 100 ° or less and a plane can have a surface roughness of 10 ° or less. I have. For example, JP-A-1-46454 reports that a silicon carbide film oriented in (111) has a surface roughness of 30 °.
Further, Japanese Patent Application Laid-Open No. 3-126667 discloses that a film oriented at (220) can have a smaller surface roughness than a non-oriented film.

[0004]

However, when various experiments were conducted based on the above-mentioned prior art, it was found that even if the film was oriented, the surface roughness of the film finally formed by polishing would vary. , There was a film in which high surface smoothness could not be obtained, and the reproducibility was poor. This means that the orientation of the film does not necessarily contribute to the surface smoothness. Therefore, in the conventional method, it is difficult to stably obtain a reflecting mirror member having excellent surface smoothness, and there have been problems such as a low yield in manufacturing.

Accordingly, an object of the present invention is to provide a reflecting mirror member coated with a high-quality silicon carbide film having excellent surface smoothness, which can be produced stably with good reproducibility.

[0006]

Means for Solving the Problems The present inventors investigated the relationship between the structure of the film and the surface roughness of those having the same orientation but different surface roughness in order to solve the above problems. As a result, we obtained a new finding that the surface roughness of the film greatly depends on the crystal structure, and based on this, repeated examinations on the optimal crystal structure, the crystal growth direction was perpendicular to the substrate surface. The inventors have found that the closer the film is to the direction, the higher the surface smoothness can be achieved when the film is polished, and have reached the present invention.

Namely, the reflecting mirror member of the present invention is made by coating a silicon carbide film on a predetermined substrate surface, in a coating member made of a crystal orientation film silicon carbide film is based on X-ray diffraction, the growth of the crystal The maximum inclination of the silicon carbide film with respect to the direction perpendicular to the surface of the base is 30 degrees or less, and the surface of the silicon carbide film is polished by plane polishing , and the surface roughness Rmax is 10 °.
It is characterized by the following .

Moreover, it covers the silicon carbide film on a predetermined substrate surface, in a coating member made of a crystal orientation film silicon carbide film is based on X-ray diffraction, perpendicular to the substrate surface of the growth direction of the crystal The maximum inclination with respect to the direction is 30 degrees or less, and the surface of the silicon carbide film is subjected to a curved surface polishing process ,
The surface roughness Rmax is 100 ° or less .

Hereinafter, the present invention will be described in detail. In the present invention, the silicon carbide film formed on the surface of the substrate is formed of a so-called crystal orientation film in which a specific crystal plane is observed in X-ray diffraction measurement. There may be more than one. For example, according to the CVD method, in the case of a silicon carbide film, (111), (220),
(311) and the like are detected.

In the film in which the crystal orientation is observed in such X-ray diffraction measurement, as is apparent from Examples 1 and 2 described later, only the (111) diffraction line was observed in the SiC film. Even a so-called (111) 100% SiC alignment film may have a large inclination with respect to a direction perpendicular to the substrate surface, and a film having such a large inclination cannot result in high smoothness.

According to the present invention, in the silicon carbide film, it is important that the crystal growth direction is parallel to the direction perpendicular to the substrate surface, and that the crystal growth direction is not more than 30 degrees even if inclined. According to the experiments of the present inventors, the larger the inclination, the larger the surface roughness when the film surface is polished, and particularly the larger the inclination exceeds 30 degrees. all right. This inclination is desirably 20 degrees or less, particularly preferably 10 degrees or less.

[0012] Based on this, the silicon carbide film of the present invention has a surface roughness (Rmax) of 100 by a curved surface polishing process.
Excellent surface smoothness of Å or less can be obtained. For example, even with a curved surface having a radius of 20 mm, a surface roughness of 100 ° or less, and in some cases, 50 ° or less can be achieved, and in plane polishing, 10 ° or less, particularly 5 ° or less can be achieved.

The silicon carbide film formed in the present invention can easily handle the raw material, has a high film forming rate, has high hardness, has a high yank rate, and has a high yank rate of 100%.
It is good for obtaining the following super smooth surface.

On the other hand, the substrate can be appropriately selected and is preferably similar in terms of thermal expansion, such as a sintered body of the same kind as the silicon carbide film and other ceramic materials or metals having thermal expansion characteristics similar to those of the silicon carbide film. Can be adopted.

As a method for manufacturing the reflecting mirror member of the present invention, a plasma CVD, a photo CVD, a thermal CVD, an MO (Metal-Or) can be used even by a PVD method such as ion plating.
g.) CVD method such as CVD. However,
According to the present invention, it is necessary that the silicon carbide film to be formed is a specific alignment film and the crystal growth method is perpendicular to the substrate. Since the orientation film may be formed at a level at which the growth rate of the film is relatively slow and does not become amorphous in a general manufacturing method, it can be appropriately adjusted depending on the concentration of the source gas and the like.

In the formation of a silicon carbide film by vapor phase epitaxy (CVD), ceramic crystals grow from the substrate surface toward the space. Then, a part of the crystal grows with a large inclination with respect to the direction perpendicular to the substrate surface. On the other hand, when the nucleus density is high, the crystals grow in a direction perpendicular to the substrate surface, and the growth directions are uniform. Therefore, the growth direction of the crystal may be controlled by controlling the growth direction of the primary crystal particles during the film formation process. Specifically, the nucleation density can be increased by introducing a large amount of a gas containing atoms serving as a reactive species of a gas phase reaction at an early stage of film formation and activating the gas at a higher temperature.

Further, according to the present invention, the film formed as described above can be polished and a super smooth surface can be stably manufactured with good reproducibility. As a specific polishing method, polishing may be performed on a surface plate using abrasive grains such as diamond.

The reflecting mirror member having an ultra-smooth surface obtained as described above is applied to various uses of a reflecting mirror requiring an ultra-smooth surface. For example, anti-reflective
It can be used for a mirror .

[0019]

As a result of examining the crystal orientation and the crystal growth direction of the silicon carbide film formed by the vapor phase epitaxy by X-ray diffraction, the direct relationship between the film orientation and the crystal growth direction is clear as will be apparent from the examples described later. In addition, it cannot be said that the surface roughness obtained by X-ray diffraction measurement even with a highly oriented film becomes small. In other words, in the film formation process, if the growth directions of the primary crystal grains are not aligned at the initial stage, a large difference appears in the growth direction between the central part and the peripheral part of the secondary particles. When this is polished, the crystal planes to be polished at the center and the periphery are different, and the hardness differs depending on the direction of the plane. The surface roughness becomes worse.

According to the present invention, the polishing direction can be made uniform by controlling the growth direction of the film as a whole in a direction perpendicular to the surface of the substrate, so that an ultra-smooth surface can be finally obtained. It is. In particular, when the inclination during growth exceeds 30 degrees at the maximum, the surface roughness sharply increases. Therefore, the growth direction is set to 30 degrees or less at the maximum.

[0021] Based on this, the reflecting mirror member of the present invention, coal
The surface roughness Rmax of the silicon nitride film is obtained by planar polishing.
Excellent surface smoothness of 10 ° or less can be obtained.
In addition, the surface roughness of the silicon carbide film is reduced by the polishing.
Excellent surface smoothness with an Rmax of 100 ° or less can be obtained.

[0022]

Example 1 A silicon carbide film was formed by thermal CVD using a silicon carbide sintered body as a substrate. Methyltrichlorosilane and hydrogen were used as the reaction gas, and these were supplied at a flow rate of 15 SLM and a substrate temperature of 1.
A film having a thickness of about 0.3 mm was formed at 300 to 1500 ° C. under a reduced pressure of 10 to 300 torr. In the initial stage of the film formation, the gas ratio of methyltrichlorosilane: hydrogen was set to 1: 4.
行 い 4:10 for 10 minutes, then 2: 1
The film was formed by fixing to 0, and several kinds of films having different maximum inclinations in the growth direction were obtained. The sample No. 4 is 2:10
To form a film.

With respect to the obtained film, the maximum inclination of the crystalline film was the one having the largest inclination in the structure observed by a micrograph from the fracture surface of the film. The crystal orientation was measured by X-ray diffraction, the film was polished with diamond abrasive grains, and the surface was polished and the surface was polished with a radius of curvature of 20 mm. Then, the surface roughness Rmax of the polished film surface was measured. The results are shown in Table 1. In the table, sample No. 1 (the present invention) and Sample No. 1 For No. 4 (outside the scope of the present invention), a micrograph of a crystal structure as shown in a micrograph was shown.

[0024]

[Table 1]

According to the results shown in Table 1, when the orientation was examined by X-ray diffraction, it was confirmed that Sample No. In Sample Nos. 1 to 4, diffraction rays of only (111) were obtained. In Nos. 5 and 6, only the diffraction line of (220) was obtained. Regarding the inclination of crystal growth, methyltrichlorosilane:
When the gas ratio of hydrogen was set to 1: 4 to 4:10, the inclination was 30 degrees or less. Further, Sample No. having a maximum inclination exceeding 30 degrees. 4 and 6, it is understood that the surface roughness of the polished surface is larger than those of the other products of the present invention. Example 2 Using a silicon carbide sintered body as a base, a silicon carbide film was formed while changing the gas ratio in the same manner as in Example 1 to obtain a reflector member, and the characteristics were evaluated. The results are shown in Table 2.

[0026]

[Table 2]

The orientation by X-ray diffraction was determined for Sample No. Since peaks of (111) and (220) were observed in 9 to 12, peak ratios are shown in the table. Sample No. In Sample No. 14, the diffraction line of (311) was also observed. 1
Nos. 1 and 13 had a large maximum crystal growth slope and large surface roughness. From this result, it was found that the crystal growth direction affected the surface roughness of the polished surface rather than the orientation.

[0028]

As described in detail above, the reflecting mirror member of the present invention can be manufactured stably with a reproducible and ultra-smooth surface as compared with the conventional reflecting mirror member, and is highly practical. A member can be provided.

[Brief description of the drawings]

FIG. 1 shows a sample of Example 1; FIG. 1 is a micrograph of a crystal structure of a micrograph of Example 1 (product of the present invention).

FIG. FIG. 4 is a micrograph of a crystal structure based on a micrograph of Comparative Example 4 (comparative product).

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C23C 16/42 C23C 16/42 G02B 1/02 G02B 1/02 G21K 1/06 G21K 1/06 B

Claims (2)

[Claims] 1. A result by coating a silicon carbide film on a predetermined substrate surface, in a coating member made of a crystal orientation film silicon carbide film is based on X-ray diffraction, perpendicular to the substrate surface of the growth direction of the crystal The maximum inclination with respect to the direction is 30 degrees or less,
And the surface of the silicon carbide film is flat polished, the table
A reflecting mirror member having a surface roughness Rmax of 10 ° or less . 2. A coating member comprising a predetermined substrate surface coated with a silicon carbide film , said silicon carbide film comprising a crystal orientation film based on X-ray diffraction, wherein said silicon carbide film is perpendicular to said substrate surface in a direction of growth of said crystal. The maximum inclination with respect to the direction is 30 degrees or less,
And the surface of the silicon carbide film is curved polished, the table
A reflecting mirror member having a surface roughness Rmax of 100 ° or less .