JPH10195655A - Silicon carbide-coating material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a silicon carbide-coating material capable of easily obtaining a super smooth surface and high precisely working a fine recessed groove similar to a grating groove in a diffraction grating. SOLUTION: The silicon carbide-coating material 1a is formed by coating the surface of a base body 2 with a silicon carbide film 3 by chemical vapor deposition. The crystal plane of the silicon carbide film 3 is strongly oriented on (222) plane in the Miller index designation and the X-ray diffraction strength of the (222) plane is >=10 times that of any plane except the (222) plane. The crystal size of the silicon carbide film 3 is <=20μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various products and parts (for example, a sealing ring of a non-contact type mechanical seal, a dynamic pressure bearing) which require a high degree of surface processing accuracy (surface roughness, surface shape accuracy, etc.). Shaft in equipment, chuck parts of vacuum chuck board, floating element, optical element such as diffraction grating, etc. for moving heavy objects such as workpiece smoothly by jet air from the board surface, wafer processing support in semiconductor manufacturing equipment, laser The present invention relates to a silicon carbide coating material suitably used as a constituent material of a molding die for one-mold molding of a glass optical element such as an instrument lens, and more specifically, to a chemical vapor deposition on a surface of a substrate. The present invention relates to a silicon carbide coating material formed by coating a silicon carbide film with a silicon carbide film.

[0002]

2. Description of the Related Art A silicon carbide coating material in which a silicon carbide film is formed on a surface of a substrate by chemical vapor deposition has a high hardness, abrasion resistance, heat resistance, chemical resistance, conductivity, and the like. Because of its superiority, especially physical
Various products requiring chemical, electrical and electronic durability,
It is expected that it can be suitably used as a component material, and is used in many fields.

For example, recently, as a spectroscopic optical element in the soft X-ray region, the surface of the silicon carbide coating material is polished to an ultra-smooth surface by an appropriate mechanical working method,
A diffraction grating manufactured by forming grating grooves on the polished surface by a chemical processing method such as etching has been proposed. Thus, due to the above-described characteristics of the silicon carbide film, such a diffraction grating is more thermally strained even for a high-intensity X-ray such as SR light than a conventional diffraction grating made of silicon or quartz. It can exhibit an excellent function such as not causing a problem. Therefore, it is indispensable for such a diffraction grating that its surface be an ultra-smooth surface and that the grating grooves be smooth and have high shape accuracy without variation in depth. , High surface processing accuracy is required.

[0004] Such a high degree of surface processing accuracy (surface roughness, surface shape accuracy, etc.) can be suitably used not only for the diffraction grating mentioned above as an example but also for a silicon carbide coating material. Most products and parts, such as sealing rings for non-contact mechanical seals, shafts in dynamic pressure bearings, chuck parts for vacuum chuck boards,
Optical elements such as a levitation stage, X-ray reflector, etc., for moving heavy objects such as workpieces smoothly by air blasting from the panel surface,
It is indispensable in a molding die or the like for one-mold molding of glass optical elements such as a wafer processing support base and a lens for a laser device in a semiconductor manufacturing apparatus.

[0005]

However, the characteristics of the silicon carbide film in the silicon carbide coating material are double-edged swords. Due to the characteristics, the surface processing accuracy (surface roughness, surface It has been pointed out that it is difficult to obtain shape accuracy, etc.), and this is a major problem for suitably using the silicon carbide coating material as a constituent material of a practical product as exemplified above.

That is, since the silicon carbide film is extremely high in hardness and excellent in abrasion resistance, it requires a long time for polishing, requires a large amount of polishing energy, and performs surface polishing on a super smooth surface. It was extremely difficult. Also, since the silicon carbide film has high hardness, it is extremely brittle, so it is necessary to form fine grooves such as a grating groove in a diffraction grating and a dynamic pressure generating groove in a sealing ring of a non-contact type mechanical seal. Even in some cases, it has been extremely difficult to machine the depth and shape with high precision. Therefore, the silicon carbide coating material is expected to be suitably used in various fields by making use of the characteristics of the silicon carbide film.
It is hardly practical in the field where a high degree of surface processing accuracy (surface roughness, surface shape accuracy, etc.) is required, and the solution is strongly demanded.

Therefore, the present inventor conducted various experiments and studies in order to determine the cause of difficulty in obtaining high surface processing accuracy in a silicon carbide film. As a result, it has been found that such a cause is mainly due to the crystal structure and crystal grain size of the silicon carbide film.

That is, in a silicon carbide film formed by chemical vapor deposition, the (111) plane of the crystal plane specified by the Miller index is higher in orientation, so that the crystal plane is usually non-oriented. In other words, the (111) plane tends to be weakly oriented, but when the surface of a silicon carbide film having such a non-oriented or weakly oriented crystal structure is polished, the polishing properties due to the difference in crystal orientation are not uniform. A high level of smooth surface cannot be obtained due to the occurrence of inter-crystal step cleavage. For example, (111)
The surface has an extremely high atomic density compared to other azimuth planes, and the chemical activity of the surface is extremely low.If the surface is polished as described above, the other azimuth plane portions are faster and It will be cut deep and many pits will be generated. Such pits cannot be eliminated no matter how carefully polished, and it becomes difficult to obtain a super smooth surface. Further, when the crystal plane of the silicon carbide film is non-oriented or shows a weak orientation to the (111) plane, when a concave groove is formed by etching, a crystal wall including a transition on the etched surface of the concave groove is formed. Appears, the crystal plane orientation differs with the transition as a boundary, and a difference occurs in the etching amount.
Inevitably, the surface of the groove serving as the etching surface becomes rough, and the groove depth varies.

Further, since the silicon carbide film is brittle, its corners are apt to be chipped at the time of processing a fine concave groove, and the depth becomes uneven or the shape accuracy is reduced. Is because the silicon carbide film is polycrystalline,
The grain boundary is generated as a starting point, and becomes more remarkable as the crystal grain becomes larger. This applies not only to the case where the grooves are formed by mechanical processing such as sand blasting but also to the case where they are formed by chemical processing such as alkali etching and plasma etching.

[0010] In order to eliminate such a disadvantage in processing, it is conceivable to make the silicon carbide film single crystal or amorphous, but it is not practical. That is, even if it is attempted to apply to a practical product as exemplified at the beginning, it is impossible with current technology to produce a product having a large size like such a practical product.

The present inventor further conducts experiments and studies on the basis of the findings to make the crystal plane strongly oriented to a specific crystal plane with a certain degree of orientation.
Unlike the case of non-orientation and weak orientation, the polishing property of the silicon carbide film is uniform, it can be polished to an ultra-smooth surface, and the orientation of the crystal plane is the strongest in the (111) plane. 220) that the surface follows this;
The (220) plane has a lower atomic density and a lower surface chemical inertness than the (111) plane.
When the silicon carbide film is strongly oriented to (0), the polishing energy of the surface of the silicon carbide film can be reduced as compared with the case where the (111) plane is strongly oriented or the case where the (111) plane is mixed and non-oriented and weakly oriented. The surface can be easily polished to an ultra-smooth surface, and by setting the crystal grains in the silicon carbide film to a certain size or less, it becomes easier to obtain an ultra-smooth surface by surface polishing, and a fine In the case of mechanically and chemically processing the groove, it has been clarified that damage or breakage originating from the crystal grain boundary can be prevented as much as possible, and a high-precision groove can be easily obtained. .

The present invention has been made on the basis of such findings, and can provide an ultra-smooth surface easily, and can process fine concave grooves such as grating grooves in a diffraction grating with high precision. It is an object of the present invention to provide a silicon carbide coating material that can be used.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a silicon carbide coating material comprising a substrate and a silicon carbide film formed by chemical vapor deposition on the surface of the substrate. (2)
20) plane, and the X-ray diffraction intensity thereof is (22).
The present invention proposes that the surface of the silicon carbide film be 10 times or more with respect to any surface other than the 0) surface, and that the crystal grain size of the silicon carbide film be 20 μm or less.

Here, "the X-ray diffraction intensity of the (220) plane becomes 10 times or more of any plane other than the (220) plane" is measured by an X-ray diffractometer (22).
0) plane peak intensity (powder X based on US ASTM standard)
(Hereinafter referred to as “X-ray diffraction peak intensity”), which was measured in the same manner (11).
1) It means that the intensity is 10 times or more of the X-ray diffraction peak intensity of a plane or the like. By the way, as described above, since the orientation of the (111) plane is the highest, when the X-ray diffraction peak intensity of the (220) plane is 10 times or more the X-ray diffraction peak intensity of the (111) plane, it is inevitable. Thus, the intensity of the X-ray diffraction peak of another crystal plane is 10 times or more. Therefore, (220)
Whether the X-ray diffraction intensity of the plane is 10 times or more with respect to any plane other than the (220) plane depends on the X-ray diffraction of the (111) plane.
Only the line diffraction peak intensity may be used as a reference.

Incidentally, the degree of orientation to the (220) plane and the size of crystal grains in a silicon carbide film formed by chemical vapor deposition are as follows:
It can be arbitrarily controlled by changing deposition conditions (deposition rate, deposition temperature, etc.), and the control method is well known. Therefore, the work of setting and selecting the vapor deposition conditions for setting the X-ray diffraction peak intensity of the (220) plane to be 10 times or more the X-ray diffraction peak intensity of the (111) plane and setting the crystal grain size to 20 μm or less is as follows. It does not involve any particular difficulty for those having ordinary knowledge in the technical field, and can be appropriately and easily performed as needed. For example, it is preferable to perform chemical vapor deposition at a vapor deposition temperature of 1350 ° C. to 1400 ° C. and a vapor deposition rate of 50 μm / h to several hundred μm / h.

The material and shape of the substrate are arbitrarily set according to products and parts such as a diffraction grating having the silicon carbide coating material as a constituent material. For example, as a constituent material of the base, C / C composite, sintered graphite, pyrolytic graphite, reaction sintered silicon carbide, normal pressure sintered silicon carbide, hot pressed sintered silicon carbide, and the like are generally used. Both β-type and α-type can be used as silicon carbide. Of course, it is also possible to use a heat-resistant hard material such as tungsten, tungsten carbide, or silicon nitride.

[0017]

FIG. 1 is a block diagram showing an embodiment of the present invention.
Or, it will be specifically described based on FIG.

FIG. 1 shows a first embodiment.
The present invention relates to an example in which the present invention is applied to a laminar type diffraction grating 1.

As shown in FIG. 1E, the diffraction grating 1 is formed by forming linear grating grooves 4 on the surface of a silicon carbide film 3 formed on a substrate 2 at equal intervals. It was produced as follows.

First, a pure β-type silicon carbide is chemically deposited in a non-oxidizing atmosphere on the surface of a substrate 2 made of sintered silicon carbide to coat and form a silicon carbide film 3. Obtain a coating material 1a (FIG. 1)
(A)). The shape of base 2 is in accordance with the final shape (shape of diffraction grating 1) obtained by coating silicon carbide film 3. Also,
The thickness of silicon carbide film 3 is appropriately set in consideration of the polishing allowance, the depth of lattice groove 4, and the like.

At this time, the crystal plane of silicon carbide deposition layer 3 is
Control of deposition temperature and deposition rate (for example, deposition temperature 135
0 ° C. to 1400 ° C., deposition rate 50 μm / h to several hundreds μ
(m / h) so that the X-ray diffraction peak intensity on the (220) plane is 10 times or more the X-ray diffraction peak intensity on the (111) plane and the crystal grains are 20 μm or less in size. ) Plane.

Next, the surface of the silicon carbide film 3 of the silicon carbide coating material 1a is polished by an appropriate mechanical working method so that the surface thereof becomes a desired ultra-smooth surface (for example, surface roughness: RMS 5 ° or less) 3a. (For example, precision polishing with diamond abrasive grains). At this time, silicon carbide film 3 is strongly oriented to the (220) plane as described above, and
Since the size is 0 μm or less, the ultra-smooth surface 3 a free from polishing scratches and pits can be obtained in a short time with a small polishing energy. The easiness and accuracy of such surface polishing is more as the degree of orientation to the (220) plane is higher (the magnification of the X-ray diffraction peak intensity with respect to the (111) plane is higher) or the crystal grain size is smaller. Will improve.

On the surface 3a of the silicon carbide film 3 thus polished to an ultra-smooth surface, linear lattice grooves 4 parallel to each other at a constant groove interval (lattice constant) are marked by ion beam etching. I do.

That is, first, a resist 5 is fixed on the polished surface 3a of the silicon carbide film 3 on the film 3 (for example, a positive resist OFPR50005 is spin-coated at 3000 ° C., and fresh air is applied at 90 ° C. for 30 minutes). Oven is performed) (FIG. 1 (B)). Then, after performing an appropriate exposure method (for example, a holographic exposure method using two-beam interference of a He-Cd laser (wavelength λ = 4416 °)), development using a dedicated developer is performed, and a resist pattern (for example, 1200 / Mm resist pattern) 5a
Is formed (FIG. 1C). At this time, by appropriately controlling the exposure and development time, the resist is dissolved in the developing solution, and the ratio (L & S ratio) between the portion where the SiC surface is exposed and the portion covered with the remaining resist is set to a predetermined value. can do. This L & S ratio is an important factor that ultimately determines the ratio of the width between the lattice groove and the lattice bank of the laminar diffraction grating. Next, this photoresist pattern 5
Using a as an etching mask, a mixed gas of Ar + CHF ₃ (mixing ratio is Ar: CHF ₃₎ from a direction perpendicular to the surface of the film 3.
₃ = 67: 33) with the ion beam 6 (FIG. 1D). Thereby, silicon carbide film 3
The exposed portion is selectively and strongly etched, and most of the resist remains without being etched because the etching rate is slower. At this time, if the crystal plane of silicon carbide film 3 is oriented strongly to the (220) plane, the etching rate is higher for the (220) plane than for the other planes. Since the retardation does not occur, the extremely smooth and highly accurate lattice grooves 4 are formed in combination with the crystal grains of the silicon carbide film 3 having a small size of 20 μm or less. When the etching depth on the surface of the silicon carbide film 3, that is, the lattice groove depth reaches a predetermined value (for example, 75 °), the irradiation of the ion beam is stopped, and then the remaining resist is ashed by O ₂ plasma. By removing and washing, FIG.
A predetermined shape shown in (E) (for example, groove interval: 1/1200)
mm, groove width / groove period: 0.5, groove depth: 75 °).

In the diffraction grating 1 thus obtained, the surface of the silicon carbide film 3 does not have a variation in depth and has a very high accuracy in the form of a grating groove 4 having no defects such as missing corners.
Are formed, and excellent functions such as exhibiting extremely high diffraction efficiency with almost no scattered light can be exhibited.

FIG. 2 shows a second embodiment, and relates to an example in which the present invention is applied to a molding die 11 for one-mold molding of various glass optical elements such as lenses.

As shown in FIG. 2, the molding die 11 is obtained by molding the molding body 12 into a predetermined shape (FIG. 2A), and forming a silicon carbide film 13 on the surface of the molding portion 12a of the molding body 12. To obtain a silicon carbide coating material 11a according to the present invention (FIG. (B)), the surface of the silicon carbide film 13 of the silicon carbide coating material 11a is polished (FIG. (C)), and the polished surface 13a is formed. This is manufactured by forming a release film 14 in FIG.

That is, the silicon carbide coating material 11a
As shown in FIG. 2A, a mold body 12 serving as a base is a sintered body of β-type silicon carbide obtained by a technique such as pressureless sintering, hot press sintering, or hot isostatic pressing. , Bulk density of 3.0 or more) into a predetermined shape. Note that the shape of mold portion 12a is in accordance with the final shape obtained by coating silicon carbide film 13 and release film 14.

The silicon carbide coating material 11a is made of silicon carbide having an appropriate thickness (for example, 200 μm) by chemically depositing pure β-type silicon carbide in a non-oxidizing atmosphere on the surface of the mold portion 12a of the mold body 12. The film 13 is formed by coating (FIG. 2B). In the silicon carbide film 13, as in the first embodiment, the crystal plane is strongly oriented to the (220) plane by controlling the evaporation conditions (e.g., evaporation temperature and evaporation rate). The X-ray diffraction peak intensity is 10 times the X-ray diffraction peak intensity of the (111) plane.
Twice or more, and the size of crystal grains is 20 μm
It is as follows.

The surface of silicon carbide film 13 has a desired ultra-smooth surface (for example, surface roughness: RMS) by an appropriate mechanical working method.
The surface is polished to 13a (shape accuracy: λ / 4 or less) 13a (FIG. 2C). Such surface polishing is performed, for example, by forming the surface of the silicon carbide film 13 in a rough shape using diamond abrasive grains and then performing precision polishing using diamond abrasive grains, as described in the first embodiment. For the same reason, the ultra-smooth surface 13a free of polishing scratches and pits can be obtained very easily with less polishing energy.

The formed surface 13a, which is a film surface finished to an ultra-smooth surface in this way, is coated with, for example, boron nitride by magnetron sputtering.
A release film 14 having a thickness of 0.5 μm or less is formed.
(D)).

According to the molding die 11 thus obtained, since the molding surface 13a is formed as an ultra-smooth surface, a high-precision optical element having an extremely smooth surface can be favorably formed by one-mold molding. Moreover, since the crystal plane of silicon carbide film 13 forming forming surface 13a is strongly oriented to the (220) plane, the thermal conductivity on forming surface 13a becomes uniform, and the thermal strain generated during forming is extremely small. Become. That is, by increasing the degree of crystal orientation in silicon carbide film 13, it is possible to significantly improve the uniformity of thermal characteristics on molding surface 13 a, to minimize the occurrence of thermal strain, and to reduce the durability of molding die 11. Performance can be greatly improved. Moreover, even when the molding surface 13a is deteriorated due to the reaction with the glass at the time of molding, the deterioration is uniform. Therefore, there is almost no variation in the precision of the molded product, and quality control becomes extremely easy.

The silicon carbide coating material according to the present invention is used not only as a constituent material of the diffraction grating and the mold described in the above embodiment, but also has a physical, chemical, electrical and electronic durability on its surface. Products that require high surface processing accuracy (surface roughness, surface shape accuracy, etc.)
Parts, for example, a sealing ring of a non-contact type mechanical seal, a shaft in a dynamic pressure type bearing device, chuck parts of a vacuum chuck board, a floating stage for smoothly moving a heavy work such as a workpiece by air blown from the board surface, a laser. It is suitably used as a constituent material such as an optical element such as a reflecting mirror and a wafer processing support base in a semiconductor manufacturing apparatus, and its use is extremely wide.

[0034]

EXAMPLE 1 As Example 1, a silicon carbide film according to the present invention in which a silicon carbide film having a thickness of 200 μm was formed by chemical vapor deposition of β-type silicon carbide on the surface of a base made of a sintered body of β-type silicon carbide. Coating material (hereinafter “coating material”)
No.). 1 was obtained. This coating material N
o. In obtaining 1, the crystal plane of the silicon carbide film is (2
20) The deposition conditions were controlled so that the crystal was strongly oriented on the plane, the degree of orientation was 10 times, and the crystal grain size was 20 μm. The degree of orientation means that the X-ray diffraction peak intensity of the strongly oriented (220) plane is the X-ray diffraction intensity of the (111) plane.
When the intensity is x times the line diffraction peak intensity, it means the magnification x, and the crystal grain size means the average size of the crystal grains in the silicon carbide film (hereinafter the same). ).

As Comparative Example 1, a coating material No. 1 having a 200 μm thick silicon carbide film (β-type silicon carbide) formed on its surface by chemical vapor deposition using a substrate having the same shape and the same material as described above. 4 and No. 4. 5 was obtained. At this time, the coating material No. In obtaining Coating Material No. 4, the crystal particle size Same as 1, but
The deposition conditions were controlled such that the degree of orientation on the (220) plane was five times. In addition, the coating material No. In obtaining 5, the deposition conditions were controlled so that the crystal plane of the silicon carbide film was strongly oriented to the (111) plane.

Each coating material No. 1, N
o. 4, No. For No. 5, the surface of the silicon carbide film was pitch-polished (polished) for 10 hours with a 1/4 μm polycrystalline diamond (medium hard pitch), and the roughness of the polished surface (R
MS). The results were as shown in Table 1. The coating material No. For No. 4, a clear step (grain boundary moat) was generated on the polished surface. Also, (11
1) Coating material No. As for 5, the surface was hardly polished after 10 hours,
A polished surface could not be obtained.

Further, each coating material No. 1,
No. 4, No. Regarding No. 5, a groove was formed on the surface of the silicon carbide film while the abrasive jet nozzle was moved in parallel along the surface of the silicon carbide film by blasting using # 800 silicon carbide abrasive grains, and formed by blasting for 5 minutes. The groove depth of the concave groove was measured. The blast was performed at a distance of 20 cm between the nozzle and the film surface, and a pressure at which abrasive particles were ejected from the nozzle: 2 kg /
cm ^2, abrasive consumption (recycled): was performed in 1l~2l conditions. The results were as shown in Table 1.

As is clear from Table 1, the crystal plane of the silicon carbide film is oriented at a certain degree or more (10 times or more) with the (220) plane.
It can be understood that the surface polishing or the surface processing can be performed with less energy and time by making the strong orientation as described above.

[0039]

[Table 1]

In Example 2, the coating material N
o. Coating No. 1 according to the present invention in which a 200 μm-thick silicon carbide film was formed by chemical vapor deposition of β-type silicon carbide on the surface of each substrate using two substrates having the same shape and material as that of No. 1. 2 and No. 3 was obtained. At this time, the coating material No. In obtaining 2, the deposition conditions were controlled so that the crystal plane of the silicon carbide film was strongly oriented to the (220) plane, the degree of orientation was 10 times, and the crystal grain size was 10 μm. . In addition, the coating material No. In obtaining Coating No. 3, the degree of orientation to the (220) plane was determined by coating material No. 3. 2, but the vapor deposition conditions were controlled so that the crystal grain size was 20 μm.

Further, as Comparative Example 2, a silicon carbide film (β-type silicon carbide) having a thickness of 200 μm was formed on the surface of each substrate by chemical vapor deposition using two substrates having the same shape and the same material as described above. Coating material No. 6 and no. 7
I got At this time, the coating material No. To obtain No. 6, the degree of orientation to the (220) plane is determined by the coating material N
o. 2 is the same as that of Coating Material No. 2 except that the crystal particle size is 25 μm. In obtaining Coating Material No. 7, the coating material No.
2, but the deposition conditions were each controlled so that the crystal grain size was 30 μm.

Each coating material No. 2, N
o. 3, No. 6, No. For No. 7, the surface of the silicon carbide film was pitch-polished (polished) with a 1/4 μm polycrystalline diamond (medium hard pitch), and the roughness of the polished surface was measured every 5 hours, and the surface roughness was reduced to RMS 10 °. The polishing time to reach was measured. The results were as shown in Table 2.

As is clear from Table 2, even when the degree of orientation to the (220) plane is the same, the polishing time required until the surface roughness becomes constant decreases as the crystal grain size decreases, In particular, it is understood that when the crystal grain size is 20 μm or less, the polishing time is drastically reduced as compared with the case where the crystal particle size exceeds 20 μm.

[0044]

[Table 2]

Further, each coating material No. 2, N
o. 3, No. 6, No. For No. 7, a groove was formed on the surface of the silicon carbide film by blasting using a No. 800 silicon carbide abrasive grain while the abrasive jet nozzle was moved in parallel along the surface of the silicon carbide film, and formed by blasting for 5 minutes. The shape accuracy of the groove was inspected. In this blast, the distance between the nozzle and the film surface: 20 cm, the abrasive jet pressure from the nozzle: 2 kg / cm ² , the amount of abrasive (circulation): 1 l
This was performed under 2 l conditions.

As a result, the coating material No. 2 and N
o. In No. 3, a concave groove with a high surface precision was obtained with a smooth surface and no chipped corners. 6 and N
o. In the case of coating material No. 7, defects such as partial chipping of corners were observed. 2 and No. It was confirmed that the shape accuracy of the groove was clearly lower than that of the groove No. 3. In particular, no. 3 was remarkable. From this, it is understood that the crystal grain size greatly affects the shape accuracy in forming the concave groove, and it is essential to keep the crystal particle size to 20 μm or less in order to secure high shape accuracy. It is understood that

Therefore, these points and Tables 1 and 2
As can be seen from FIG. 2, the degree of orientation to the (220) plane in the silicon carbide film is 10 times or more, and the crystal grain size is 20 times.
It is understood that the surface polishing or surface processing can be performed extremely easily and with high accuracy by setting the thickness to μm or less.

[0048]

As can be easily understood from the above description, according to the present invention, the crystal plane of a silicon carbide film formed by chemical vapor deposition is oriented strongly to the (220) plane (the X-ray diffraction intensity of the (220) plane). Is 1 for any plane other than the (220) plane
0 times or more) and the crystal grain size is 2
By setting the thickness to 0 μm or less, surface polishing or surface processing (including groove processing) of the silicon carbide film can be performed extremely easily and with high precision. Therefore, it is suitable for use as a component of various products and parts such as diffraction gratings that require a high degree of surface processing accuracy (surface roughness, surface shape accuracy, etc.) without causing the processing problems described at the beginning. A silicon carbide coating material that can be used.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment.

FIG. 2 is a sectional view showing a second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Diffraction grating, 1a, 11a ... Silicon carbide coating material, 2 ... Base, 3,13 ... Silicon carbide film, 3a, 13a ...
Polished surface (ultra-smooth surface), 4 ... Lattice groove, 11 ... Mold, 1
2. Mold main body (base).

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01L 21/68 H01L 21/68 N // F16C 3/02 F16C 3/02 F16J 15/34 F16J 15/34 F

Claims (1)

[Claims] 1. A silicon carbide coating material formed by coating a surface of a substrate with a silicon carbide film by chemical vapor deposition,
The crystal plane of the silicon carbide film is expressed as (22
0) plane, and its X-ray diffraction intensity is (220)
A silicon carbide coating material characterized in that the thickness is 10 times or more with respect to any surface other than the surface, and the crystal grain size of the silicon carbide film is 20 μm or less.