JPH10244144A - Pressure partition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a pressure partition wall superior in light transmission characteristics in a high yield and at a low cost by using diamond obtained by a gas phase synthetic method as a pressure partition wall raw material for partitioning two spaces different from pressures, and arranging the partition wall raw material such that a low pressure side is projectedly. SOLUTION: In the pressure partition wall used to a pressurizing device, etc., especially a window for ultra high vacuum device, etc., having light transmission property in a broad range and also having >= one atm pressure resistance, the diamond obtained by the gas phase synthetic method is used as the partition wall raw material 11. A thin diamond plate obtained by the gas phase synthetic method causes frequently to warp by stress induced at a time of the synthesis. The thin diamond plate is normally set such that the low pressure side is projectedly. At this time, a warp value |ΔH|between the peripheral part of the partition wall raw material 11 and the central part is made into 5μm<=|ΔH|<=100μm, especially 15μm<=|ΔH|<=80μm, thus the leakage is reduced and the yield is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure partition used for a vacuum device or a pressurizing device, and more specifically, has a wide range of light transmittance, such as a window for an ultra-high vacuum device, and has a pressure of 1 atm. The present invention relates to a pressure bulkhead having a higher pressure resistance. In this specification, “pressure barrier” is different from
Means for stably holding the isolating material to separate the two spaces.

[0002]

2. Description of the Related Art In an apparatus in which the inside is in an ultrahigh vacuum or pressurized state, a pressure partition for separating the inside of the apparatus from the outside or dividing the inside of the apparatus is an essential part. In particular, there is a strong demand for a pressure barrier made of a material that efficiently transmits light in a wide range of wavelengths for observation or measurement. The performance required for these pressure bulkheads is
Even if the desired pressure difference is set on both sides of the partition, it functions stably without pressure leakage, and of course, has good light transmittance in vacuum ultraviolet to visible light, infrared light, or a wider wavelength range. It is necessary to be. For such applications, especially for windows to be attached to vacuum equipment, CaF ₂ , LiF, BaF ₂ , N
aCl and the like have been used. However, these materials have a large difference in the coefficient of thermal expansion from the flange used for mounting the device, and have a low mechanical strength.
There is a problem that cracking is apt to occur when baking for vacuum gas release.

In order to avoid such a problem, the following method has been developed. That is, this is a method of joining the flange and the partition wall material via a joining frame and a joining material.
In this method, in particular, in this method, a force acts on the light transmitting window plate when the inside of the container is in a vacuum state, and light is applied when an external force is applied to the outside of the container without the inside of the container being in a vacuum state. Even if the transmission window plate is pressed in the direction from the upper opening side to the lower opening side of the frame member under pressure,
Since the force is received by the flange on the lower opening side of the frame member, stress is less likely to be generated in the seal portion, so that the sealability can be maintained.

Further, by using diamond as the partition wall material, light in a wide wavelength range can be efficiently transmitted, and the mechanical strength is strong, so that the partition wall material is hardly damaged. In particular, plate-shaped diamonds having a large area can be produced relatively inexpensively by using diamond produced by a vapor phase synthesis method (hereinafter referred to as vapor phase synthetic diamond), whose production technology has been remarkably advanced in recent years. By using this as a partition wall material, it has become possible to obtain a pressure partition wall having a wide opening diameter and capable of efficiently transmitting light of a wide wavelength. In this structure, breakage is also prevented by the joining material serving as a pressure seal and the joining frame playing a role of absorbing stress (Japanese Patent Laid-Open No. 9-3).
No. 3704). There is a demand for a pressure partition wall used in these devices, which further efficiently transmits light having a large area and a wide range of wavelengths.

[0005]

By using such a known joining frame and joining material, it is possible to obtain a pressure partition wall which can withstand a high vacuum and can be baked at a high temperature. However, there are the following problems in using a pressure partition using vapor-phase synthetic diamond as a material for the partition. When a vacuum or pressure test is performed, leakage (leakage) frequently occurs and the yield is not good. High production cost of CVD diamond for partition wall material. In addition, there is some light loss due to absorption and scattering inside the material,
A material with a small thickness is required. However, if it is too thin, cracking or peeling of brazing occurs. When far-infrared light (wavelength of 50 μm or more) is transmitted, the order of the transmission wavelength and the film thickness becomes close, interference on both sides of the window material increases, and the light cannot be transmitted uniformly. The present invention has been made in order to solve the above problems, and has been devised in shape, structure and arrangement of a material for a partition made of diamond by a vapor phase synthesis method, devised a supporting method, has excellent mechanical strength, and has a light It is an object of the present invention to provide a pressure partition having excellent transmission characteristics with good yield and low cost.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the inventors have conducted intensive studies and completed the present invention. That is, the present invention provides (1) a pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a gas phase synthesis method, and the material of the partition mainly has a low pressure. A pressure bulkhead which is arranged so as to be convex toward the side, (2) when the magnitude | ΔH | of the warpage of the peripheral part and the central part of the bulkhead material is 5 μm ≦ | ΔH | ≦ 100 μm The pressure bulkhead according to claim 1, wherein (3) a pressure bulkhead for separating two spaces having different pressures, wherein at least the bulkhead material is made of diamond obtained by a gas phase synthesis method, A pressure bulkhead, which is mainly arranged on the low pressure side so as to be the substrate surface,

(4) A pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a vapor phase synthesis method, and the material of the partition is mainly formed on the lower pressure side. A pressure bulkhead, wherein the warpage is arranged to be convex, and the low-pressure side is arranged so as to be the substrate surface, (5) a pressure bulkhead for separating two spaces having different pressures, at least The partition wall material is made of diamond obtained by a gas phase synthesis method,
(6) The thickness of the thin part is 20 μm or more and 150 μm or less, and the ratio of the thin part to the thick part in the peripheral part is 5 μm.
% To 80% or less, the pressure bulkhead according to the above (5),

(7) A pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a vapor phase synthesis method, and the cross-sectional shape passing through the center thereof is trapezoidal. (8) The pressure bulkhead according to the above (7), wherein the trapezoidal taper angle (1) is 5 ° or more and 25 ° or less.
(9) A pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a gas phase synthesis method, and the material of the partition is mainly warped toward a lower pressure side. Is disposed so that the low pressure side is the substrate surface, the partition wall material is characterized by the presence of a thin portion in the center of the pressure partition wall,

(10) A pressure partition for separating two spaces having different pressures, wherein the material of the partition is made of diamond obtained by a vapor phase synthesis method, and the material of the partition is warped mainly toward the low pressure side. Are provided so that the bottom surface is convex and the low-pressure side is the substrate surface, and the cross-sectional shape passing through the center is trapezoidal.

In the pressure partition of the above (1), a diamond thin plate as a partition material is set so that the low pressure side is convex. Normally, the direction in which pressure is applied when a pressure partition is used is constant. Therefore, the direction in which the pressure increases when viewed from the partition during use is defined as the high pressure side, and the direction in which the pressure decreases as the low pressure side. On the other hand, in general, a thin diamond plate obtained by a gas phase synthesis method often causes warpage due to stress introduced during synthesis. At this time, a diamond thin plate made of a partition wall material is set so that the lower pressure side is normally convex. The amount of warpage is defined as shown in FIG. 1 (FIG. 1). Then, as shown in (2), the warpage magnitude | ΔH | of the peripheral part and the central part of the partition wall material 11 is 5 μm ≦ | ΔH | ≦ 100 μm, especially 15 μm.
It is preferable that m ≦ ΔH ≦ 80 μm. As a result, the leakage is reduced and the yield is improved, leading to a reduction in cost.

In the pressure partition of the above (3), a diamond thin plate of a partition material is set so that the substrate surface side is on the low pressure side. Generally, a diamond thin plate 22 obtained by a gas phase synthesis method is a substrate 21 made of silicon, molybdenum or the like.
It is obtained by growing on the substrate and then removing the substrate 21. The surface that was in contact with the substrate during the growth of the diamond thin plate was defined as the substrate surface 23, and the growth surface was defined as the growth surface 24 (FIG. 2), and the diamond thin plate was set so that the substrate surface side was on the low pressure side. According to the present invention, breakage of the partition walls is reduced, and the plate thickness can be reduced, so that high transmittance can be obtained. The pressure partition of the above (4) has the features of the above (1) and (3). That is, reduction in cost and achievement of high transmittance can be realized.

In the pressure bulkhead of (5), a diamond thin plate in which the thickness of the central part 33 is smaller than that of the outer peripheral part 32 is set as the bulkhead material 31 (FIG. 3). As described in (6) above, the thickness of the thin portion is 20 μm or more and 150 μm or less, preferably 50 to 120 μm, and the ratio to the thin portion of the peripheral portion is 5% or more and 80% or less (particularly 10 to 60%). ) Is preferable. Thereby, high transmittance is realized and the yield is improved. In the pressure bulkheads of the above (7) and (8), a diamond thin plate having a wedge-shaped taper angle θ is set as the bulkhead material 41 (FIG. 4). In particular, the taper angle is 5 ° or more and 25 ° or less. Is preferred. Thereby, high transmittance can be realized at a long wavelength.

The above (9) and (10) have the features of (1), (3) and (5) and the features of (1), (3) and (7), respectively, and (9) is The high transmittance realizes the improvement of the yield, and the above (10) can realize the high transmittance at a long wavelength to improve the yield.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Normally, a vapor-phase synthetic diamond thin plate is warped due to residual stress at the time of synthesis. The present inventors have studied in detail the leak generation mechanism of a pressure bulkhead using a vapor-phase synthetic diamond as a bulkhead material, and focused on the warpage of the material. By controlling this, the leak generation is greatly reduced. I found something.

When a diamond thin plate is attached by brazing or the like, both sides of the thin plate have the same pressure, and the diamond thin plate is not subjected to an external force. However, when used, the diamond sheet receives stress from the high pressure side to the low pressure side. If the high pressure side is mounted so as to be convex at the time of mounting, when a pressure is applied during use, the warp is reversed and a stress is applied so that the low pressure side becomes convex. This means that an excessive stress is generated in the diamond thin plate and the brazed portion, and is a main factor of the leak. Conversely, if the low-pressure side is set so as to be convex from the time of attachment, no stress that reverses the warp is applied. When compared under the same conditions (diamond plate thickness, pressure difference, etc.), it was found that the stress applied to the diamond thin plate and the brazing portion was smaller when the low pressure side was convex. As a result, it is possible to reduce the leakage due to breakage of the brazing portion and the diamond plate.

[0018] Vapor-phase synthetic diamond is synthesized in a film form on a substrate such as silicon or molybdenum. The diamond is grown to a thickness of several tens to several hundreds of micrometers, and then the substrate is removed to obtain a thin diamond plate. In this diamond synthesis, many diamond nuclei are generated on the substrate,
It gradually grows into a large column. Therefore, the obtained diamond has small particles near the substrate and gradually increases in size. If the surface that was in contact with the substrate at the time of growth is the substrate surface and the surface that was the growth surface is the growth surface,
The substrate surface has fine particles and the growth surface is large. Since the diamond thin plate often has such a structure, it has been found that a difference occurs in the strength. That is, it was found that the strength of the thin plate was about twice as large when the substrate surface was on the high pressure side and when the growth surface was on the high pressure side. As a result, the plate thickness required for the partition wall material can be reduced by about 30%, which is effective for reducing costs and also for improving light transmission characteristics. Furthermore, by manufacturing a diamond thin plate so that the substrate surface side is convex, and mounting it so that the substrate surface side is at a low pressure, it is possible to prevent leakage due to brazing parts, breakage of the diamond plate, and reduce the required plate thickness. It is also possible to achieve a reduction in light transmission characteristics.

The required properties of the pressure partition include mechanical strength capable of withstanding a pressure difference and a leaktight structure.
In addition, the light transmission characteristics are also important characteristics. Diamond exhibits excellent transmission characteristics from vacuum ultraviolet to far-infrared. From this viewpoint, diamond is also an ideal material for a partition wall material, but partially has an absorption band. In addition, the vapor-phase synthetic diamond has been able to have a transmittance close to that of a single crystal diamond due to the development of synthetic technology in recent years, but a slight decrease in transmittance may occur due to impurities and scattering at grain boundaries. . Along with the above-mentioned absorption band, if the plate thickness is large, its transmittance will decrease, so it is better to make the plate thickness as thin as possible, but if it is made too thin, cracks and increased stress on the brazed part This causes a problem such as leakage.

Therefore, the inventors of the present invention have proposed a plate thickness and transmission characteristics,
The relationship between mechanical properties was studied in detail. And
It has been found that by reducing the thickness of the plate only at the center and increasing the thickness of the periphery, it is possible to achieve both mechanical strength and transmission characteristics. Since there is a thick diamond around, the stress applied to the brazed portion hardly changes. In addition, the radius of the thin portion can be reduced, and the diamond material is less likely to crack. The thickness depends on the size of the region of the thin portion, the ratio with the thickness of the peripheral portion, and the pressure applied to the partition wall.
20 μm or more and 150 μm or less, especially 50 μm or more and 120 μm
m or less and the ratio of the peripheral portion with a small thickness to 5% or more 8
It is preferably 0% or less, particularly preferably 10% or more and 60% or less.

As a method of forming a thin region at the center of the vapor phase synthetic diamond partition in this manner, there are a method by laser processing, a method by selective etching, and the like. Further, a diamond thin plate is manufactured so that the substrate surface side is convex, the film thickness in the central portion is thinned, and the diamond thin plate is attached using the thin film so that the substrate surface side has a low pressure. It is possible to prevent the plate from being damaged, reduce the required plate thickness, and further improve the light transmission characteristics. Diamond is transparent to light in the far infrared region (wavelength of 10 μm or more). However, diamond has a high refractive index, and the reflectance at the air / diamond interface is as large as about 10%. The thickness of the diamond material when used as a pressure bulkhead is 10 to several hundred μm, but when the thickness is uniform over the entire surface,
Interference occurs due to reflection on the surface, and uniform transmittance cannot be secured over a wide range of wavelengths.

Therefore, the diamond partition wall is formed in a wedge shape so that the plate thickness is uniformly changed throughout (FIG. 4). By doing so, the interference condition is not satisfied by the entire partition, and the original transmission characteristics of the material can be secured uniformly over a wide wavelength range. At this time, if the taper angle θ is defined as shown in FIG. 4, the angle is preferably 5 ° to 25 °. Furthermore, by manufacturing a diamond thin plate so that the substrate surface side is convex, performing the above-mentioned taper processing, and mounting the thin plate using the substrate so that the substrate surface side is at a low pressure, the leakage due to the brazing portion, breakage of the diamond plate is reduced. In addition, the required thickness can be reduced and the light transmission characteristics of a wide range of wavelengths can be improved. The pressure bulkhead of the present invention is, for example, a diamond bulk material of Ag,
Ti, Si, Ni, Au, A in a metal frame of Au, Cu, etc.
g, AgCl, Au-Si, Au-Sn, Ag brazing or the like as a bonding material, and can be manufactured. In this case, the surface of the region to be bonded with diamond may be subjected to a metallization treatment using, for example, Au / Mo / Ti or Au / Pt / Ti layers. Hereinafter, the present invention will be described in more detail with reference to Examples, but is not intended to limit the scope of the present invention.

[0021]

【Example】

(Example 1) Si was formed by microwave plasma CVD.
Diamond was synthesized on the substrate. After polishing the growth surface, the Si substrate was dissolved and removed, and 15 mmφ × 0.2 mmt
Were obtained (Samples A to D). The warpage was as shown in Table 1 below.

[0022]

[Table 1]

This was brazed to a φ70 ICF flange (ICF: flange standard) by the method disclosed in JP-A-9-33704. Ag was used as the metal frame, and AgCl was used as the brazing material. Metallization is Au / Pt / T
i. All were brazed so that the substrate surface was on the low pressure side. This was attached to an ultra-high vacuum device and subjected to a vacuum pressure test.
As a result, the samples A and B had a leak rate of 10 ^-4 Torr.
・ It was more than liter / s, but both C and D were 10 ^-9
It was less than Torr · liter / s (measurement limit).

(Example 2) As in Example 1, samples E to
K was obtained and brazed to a φ70 ICF flange. However,
The thickness of the diamond is different. As a result of the same test as in Example 1, the sample G was broken during the evacuation, but the sample K having a smaller film thickness was not broken because the pressure on the substrate surface side was low. The results are summarized in Table 2.

[0025]

[Table 2]

(Embodiment 3) As in Embodiment 1, a 20 mm
φ × 250 μmt vapor-phase synthetic diamond sheet sample L,
M and N were obtained. The center of the sample L was 4 mm in diameter using an excimer laser beam.
μm, and for sample M, 120
μm was deleted. As shown in FIG. 3, diamond thin plates L and M having a central portion of φ4 mm and thin portions (L: film thickness of 50 μm, M: film thickness of 10 μm) were obtained. After the acid treatment, samples L, M, and N were brazed to a φ70 ICF flange in the same manner as in Example 1. The brazing direction was such that the low-pressure side was convex on the substrate surface side. A vacuum test was performed in the same manner as in Example 1. As a result, samples L and N showed good characteristics with a leak rate of 1 × 10 ⁻⁹ Torr · liter / s or less, but M showed a diamond partition wall during evacuation. Cracked. Further, infrared light having a wavelength of 3 μm was transmitted through the central portion φ3 mm, and the transmittance thereof was measured. As a result, the sample L was 55%, but the sample M was 68%.
Improved.

(Embodiment 4) As in Embodiment 1, a 20 mm
Φ × 200μmt vapor-phase synthetic diamond sheet sample O,
P was obtained. The sample P was further tapered by 9.5 ° by mechanical polishing as shown in FIG. Wavelength 50-500 μm
When the transmittance in the (far-infrared region) was measured, the sample O would transmit only a specific wavelength due to intense interference, but the sample P could maintain a transmittance of 65% or more over the entire wavelength region. Was. Both samples O and P were brazed to a φ70 ICF flange as in Example 1. The brazing directions were all convex on the low pressure side and on the substrate surface side. When a vacuum test was carried out in the same manner as in Example 1, both of them showed good characteristics with a leak rate of 10 ⁻⁹ Torr · liter / s or less.

[0028]

According to the pressure barrier of the present invention, the production yield is greatly improved. Moreover, the manufacturing cost can be further reduced by reducing the thickness of the diamond material. Further, the transmittance in a wide range can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing the definition of warpage of a partition wall material according to the present invention.

FIG. 2 is a schematic explanatory view showing the definition of the surface direction of the partition wall material in the present invention in the order of steps.

FIG. 3 is a view showing one embodiment in which the central portion of the partition wall material in the present invention is thinned.

FIG. 4 is a view showing one embodiment in which a partition wall material in the present invention is tapered.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Partition material 21 Substrate 22 Vapor-phase synthetic diamond 23 Substrate surface 24 Growth surface 31 Partition material (central part thinned) 32 Peripheral part 33 Central part 41 Partition material (having a taper)

Continuation of front page (72) Inventor Yoshiaki Kumazawa 1-1-1, Koyokita, Itami-shi, Hyogo Sumitomo Electric Industries, Ltd. Itami Works

Claims (10)

[Claims] 1. A pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a gas phase synthesis method, and the material of the partition is mainly warped on a low pressure side. A pressure bulkhead, wherein the pressure bulkhead is arranged so as to be convex. 2. The pressure bulkhead according to claim 1, wherein the warpage magnitude | ΔH | of the peripheral part and the center part of the bulkhead material is 5 μm ≦ | ΔH | ≦ 100 μm. 3. A pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a gas phase synthesis method, and a substrate surface is mainly on a low pressure side. A pressure bulkhead, which is arranged. 4. A pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a gas phase synthesis method, and the material of the partition is warped mainly toward a low pressure side. Are arranged so as to be convex, and are arranged such that the low-pressure side is the substrate surface. 5. A pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a gas phase synthesis method, and a portion having a thin film is present at the center thereof. A pressure bulkhead. 6. The thickness of the thin portion is 20 μm or more and 1
5% or less of 50 μm or less and the peripheral part where the film thickness is large
The pressure partition according to claim 5, wherein the pressure partition is at least 80%. 7. A pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a vapor phase synthesis method, and a cross-sectional shape passing through the center thereof is trapezoidal. A pressure bulkhead. 8. The trapezoidal taper angle (1) is not less than 5 ° and 2
The pressure bulkhead according to claim 7, wherein the angle is 5 ° or less. 9. A pressure partition for separating two spaces having different pressures, wherein at least the material of the partition is made of diamond obtained by a gas phase synthesis method, and the material of the partition is warped mainly toward the low pressure side. A pressure bulkhead, which is arranged so as to be convex and is arranged so that the low-pressure side is the substrate surface, and wherein the bulkhead material has a thin portion at the center. 10. A pressure partition for separating two spaces having different pressures, wherein the material of the partition is made of diamond obtained by a gas phase synthesis method, and the material of the partition is warped mainly toward the low pressure side. A pressure bulkhead, which is arranged so as to be convex, is arranged so that the low-pressure side is the substrate surface, and has a trapezoidal cross section passing through the center thereof.