JPH06289145A - X-ray window member and manufacture thereof - Google Patents

Abstract

PURPOSE:To improve the transmission performance, durability, and pressureproofness and prolong life by selectively etching-treating the center part of a gas phase synthesized diamond farmed on a substrate, forming the left thin part to an X-ray transmission part, and forming the part which is not etching-treated to a back-up grid. CONSTITUTION:The upper part of a substrate 1 made of metal, ceramics, etc., is coated with a diamond film 2 having a thickness of 10-50mum through the gas phase synthesizing method. Then, a mask 3 is formed on the film 2, and the film 2 is selectively etching-processed to a thickness of 0.3-1mum, and a left thin part is formed to an X-ray transmission part, and the left thick part is formed to a back-up grid. The peripheral edge part of the reverse surface of the substrate 1 and the side surface are covered by each, resist 4, and etching is performed, and the center part is removed, leaving only the peripheral edge part as skelton. Through this manufacturing method, the close adhesiveness is improved, since the film 2 and the back-up grid are formed integrally, and the generation of stress difference between both is prevented, and also the strength for the pressure difference between the inside and outside is large, and an excellent window free from leak can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an X-ray window material. In recent years, analyzers using X-rays have come to be used in a very wide field of industrial technology. Its performance has also made great strides. Although there are various devices, the structure, composition, impurities, etc. of a substance can be quantitatively analyzed by utilizing its short wavelength and strong transmittance.

Above all, the energy-dispersive X-ray microanalyzer has an advantage that a two-dimensional element distribution can be easily analyzed with a relatively high resolution. Therefore, it is widely used in the analysis of various substances. The present invention relates to a method for manufacturing an X-ray window material used as a partition between an X-ray detector and a sample chamber in an energy-dispersive X-ray microanalyzer.

[0003]

2. Description of the Related Art The window material of an X-ray apparatus is used to close the window between the outside under atmospheric pressure and the inside of the apparatus in a vacuum state. The window is an opening for passing X-rays. The window material must therefore be able to withstand a pressure difference of 1 atmosphere and have a low x-ray loss.

Materials that are generally light and robust are considered suitable. This is because light elements absorb less X-rays. Metal foil is often used. Light metal is A
Although I can easily think of l, the Al foil does not have sufficient strength when it has a thickness that allows X-ray transmission.

Therefore, Be has been often used as the material of the X-ray window of the conventional energy dispersive X-ray microanalyzer. B
This is because e has a small atomic number and is light in weight and relatively well transmits X-rays. Moreover, it is mechanically strong and much stronger than Al foil. However, even a Be window, if it is thin enough to pass X-rays, still lacks mechanical strength.

In order to withstand the pressure difference of 1 atm, Be is several tens μ
A thickness of m or more is required. If it is thick like this, the transmission loss of X-rays increases. If the loss is large, the power of X-rays extracted to the outside is small and the detection sensitivity is lowered. It can also heat and damage the windows.

In recent years, it has become possible to synthesize diamond and diamond-like carbon films by the vapor phase synthesis method. Therefore, a window material mainly composed of a carbon film manufactured by a vapor phase synthesis method has been proposed.

Since diamond has a larger atomic number than Be, diamond has a greater ability to shield X-rays. If the thickness is the same, Be has better X-ray transmittance. However, since diamond is superior in mechanical strength to Be, the film thickness can be made thinner. For example, the diamond film can be used as an X-ray window material even if it is thinned to 0.3 μm to 1 μm. Be cannot be very thin like this, and a film thickness of 10 μm or more is required.

As described above, the thin diamond film X-ray window material can transmit X-rays from light elements such as nitrogen and oxygen, which cannot be achieved by conventional Be window materials.
Nitrogen and oxygen are elements that are present in abundance, so most of them are contained in many samples. Since the sample is analyzed, it is desirable to know the ratio of all elements. It is strongly desired that the analyzer can measure the amounts of oxygen and nitrogen. There are various methods of analysis using X-rays, and there is also a method of measuring the characteristic X-rays emitted by the substance to identify the substance.

Since the conventional Be window material has large absorption, it does not pass the characteristic X-rays from light elements such as oxygen and nitrogen, so that light elements cannot be measured. However, since quantitative measurement of oxygen and nitrogen is strongly desired, an X-ray window material capable of transmitting characteristic X-rays from these light elements is required. By thinning the diamond X-ray window material, X-rays from light elements can pass through. The use range of the X-ray measuring device can be expanded by using diamond. Diamond is also chemically stable. For this reason, diamond is generally superior to Be as an X-ray window material.

[0011]

The diamond film produced by the vapor phase synthesis method is very thin. Therefore, the mechanical strength is insufficient. To supplement the mechanical strength, it is necessary to attach a reinforcing material to the diamond surface. The reinforcing material is called a backup grid.

Conventionally, metals such as Si, Mo and Al have been used as a backup grid for reinforcing the diamond film. For example, JP-A-2-199099 proposes such a backup grid.
Diamond is grown on these metals and most of the metal is later removed to form a backup grid. Alternatively, diamond is grown on the substrate and a mask is used to partially deposit metal on the diamond. Alternatively, a metal is vapor-deposited uniformly on diamond and is etched by photolithography leaving a partial frame. There are several ways to make a metal backup grid.

However, metals such as Al, Si and Mo have weak adhesion strength to the diamond film. Therefore, the diamond film cannot be sufficiently reinforced. The diamond film and the backup grid gradually separate. Therefore, the life of the X-ray window material is short. Further, these metals receive X-rays and generate intrinsic fluorescent X-rays. The fluorescent X-rays from the backup grid are superimposed on the intrinsic X-rays from the sample as noise. This noise lowers the detection limit of X-rays from the sample.

Further, the coefficient of thermal expansion of the material of the backup grid and that of diamond are considerably different. The vapor phase synthesis method of diamond is performed in a considerably high temperature atmosphere. If the temperature is lowered to room temperature after forming the diamond thin film, strong thermal strain occurs between the diamond film and the backup grid. Therefore, the window material may be damaged or deformed.

Such problems of low adhesive strength, fluorescent X-rays and difference in coefficient of thermal expansion are unavoidable as long as the backup grid is made of a material different from diamond. Therefore, an X-ray window material having a backup grid formed of diamond itself has been proposed. JP-A-4-127100.

Diamond is grown on a substrate such as Si by a vapor phase synthesis method. A mask for suppressing the growth of diamond is formed on this. Further, diamond is grown by the vapor phase synthesis method. Diamond does not grow in the portion covered by the growth restraint mask. The part exposed from the mask is covered with diamond. This will be the backup grid. The central portion of the bottom of the Si substrate is removed by etching. Thus, a diamond thin film X-ray window material having a diamond backup grid is formed.

In this X-ray window material, the thin film and the backup grid are made of the same material, so that the bonding strength between them is large. Further, since the coefficient of thermal expansion does not differ, thermal strain does not occur even if the temperature is changed from a high temperature to room temperature. No fluorescent X-rays are generated either. Thus, the X-ray window material having the diamond backup grid formed on the diamond thin film has excellent characteristics.

Incidentally, in order for diamond to exhibit sufficient reinforcing performance as a backup grid,
A 100 μm thick diamond is required.

When diamond is formed by the vapor phase synthesis method,
Diamond grows isotropically. As the diamond grows thicker, it gradually grows beyond the lines of the mask. The diamond also grows so as to cover the mask-covered surface and lines. When the mask is etched away with a chemical, a diamond reinforcement frame remains. However, since the diamond grows so as to cover the groove and the opening, the aperture ratio that the mask is trying to define cannot be obtained.

[0020]

In the X-ray window material of the present invention, a thickly formed vapor phase synthetic diamond is selectively etched to leave a frame body, which serves as a backup grid. That is, thick diamond is first uniformly formed, and the diamond is etched to be thin, leaving a backup grid. The thin part becomes the X-ray transmission part, and the thick remaining part becomes the backup grid.

No material other than diamond is bonded to diamond like the conventional diamond X-ray window material. The integrally formed diamond itself is selectively etched to leave a part of it in a frame shape to form a backup grid for reinforcement. The material is uniform.

The manufacturing method of the X-ray window material of the present invention will be described below with reference to FIG. FIG. 1 (a) shows a substrate 1 on which diamond is deposited. As the material of the substrate, any diamond can be used as long as it can be uniformly formed on the diamond. Since high temperature is used in the vapor phase synthesis method, it is preferable that it can withstand high temperatures, be robust, and have a small difference in coefficient of thermal expansion from diamond. Si, M
Metals such as o, W and Ta, and ceramics such as SiC and SiN are desirable. The thickness of the substrate is preferably about 0.3 mm to 1 mm in consideration of handling in a later process and easiness of etching.

FIG. 1B shows a state in which the diamond film 2 is thickly coated on the substrate 1 by the vapor phase synthesis method. The thickness of the diamond film is preferably about 10 to 50 μm in order to obtain strength as a backup grid. As the vapor phase synthesis method, filament CVD, microwave plasma CVD, plasma jet method or the like can be used. Since this thick diamond is formed by forming diamond on a uniform flat surface, it has a uniform structure and excellent strength.

FIG. 1C shows a state in which the mask 3 is provided on the diamond film. A mask 3 that covers a portion to be a backup grid later is formed by a normal photolithography technique. The backup grid is a crosspiece for reinforcement. The shape distribution is arbitrary. It may be a crosspiece in which many pieces are arranged in parallel in the vertical and horizontal directions. It may be repeated like a turtle shell, or may be a regular triangle. It is also possible to simply provide a plurality of parallel reinforcing bars. The portion not covered with the mask 3 is a portion that will become a thin permeable film later. The material of the mask is Au, Ni, Al, Si
Etc. can be used.

Here, the size and shape of the backup grid must be determined. It is characterized by the width, height, length, distribution, etc. of the individual reinforcing bars. Generally, it can be defined by the aperture ratio. The opening ratio is the ratio of the opening area to the total area. The opening is a portion where a thin diamond permeable film exists.
The ratio of the area of the shielding part covered by the backup grid to the total area is called the shielding rate. The sum of the aperture ratio and the shielding ratio is 1.

A large aperture ratio has the advantage of high X-ray transmittance. However, it lacks strength. On the contrary, when the aperture ratio is small, the strength is high, but there is a drawback that the X-ray transmission becomes insufficient. Therefore, in the present invention, the aperture ratio is 70
It is desirable to be up to 90%. The remaining 30 to 10% is the shielding part where the backup grid can exist. The backup grid must be fairly thick in order to obtain sufficient reinforcement in a small area.

FIG. 1D is a sectional view of the substrate, film and mask after etching. For the etching, dry etching such as reactive ion etching is used. The diamond film in the portion not covered with the mask 3 is largely shaved, and an extremely thin diamond layer remains. This is the part that becomes the permeable membrane. The ratio of this part to the whole is the aperture ratio. The portion covered by the mask is not etched and remains as it is.

The thickness of the permeable membrane left as a thin membrane is an important parameter. If this is thick, the pressure resistance is excellent, but the X-ray transmission becomes poor. Especially, the transmittance of low energy X-rays from light elements having a low atomic number becomes low. On the contrary, if the permeable membrane is thin, X-rays pass through well, but the pressure resistance is insufficient. In order to satisfy both conditions, the thickness of the permeable membrane is preferably about 0.3 μm to 1 μm. The unetched portion remains on the permeable membrane. This will be the backup grid. The height of this is 10 to 50 μm as described above.

FIG. 1E is a sectional view showing a state in which the peripheral portion and the side surface of the back surface of the substrate 1 are covered with the resist 4. In this state, the substrate is etched. Then, the central portion of the substrate is removed, leaving only the peripheral portion. The peripheral portion of the substrate is a skeleton portion. This is the same size as the skeleton of the peripheral edge of the diamond film. Since the central part of the substrate is completely removed, the front and back surfaces of the diamond film are exposed. Most of the diamond in the center is a permeable membrane, but there are reinforcing backup grids in the vertical and horizontal directions.

FIG. 1F is a sectional view showing a state in which the mask 3 and the resist have been removed. The product thus created is an X-ray window material. The skeleton of the diamond and the skeleton of the substrate remain on the periphery. There is no substrate material in the center. There is only a permeable membrane of diamond and a backup grid. Then, the peripheral portion of the substrate is fixed to a metal mounting frame (not shown) to form an X-ray window material.

With this manufacturing method, the X-ray window material of the present invention can be manufactured well. However, this requires an operation of etching so as to uniformly leave a very thin film when forming a permeable film. This is a difficult operation in which the etching depth is kept the same over a fairly large area and the etching is stopped at 0.3 to 1 μm.

That is, this manufacturing method requires accurate control of the diamond etching rate. If it is difficult to accurately control the etching rate over a wide area, the following manufacturing method can be used.

In this method, a diamond film is first synthesized by the thickness of the permeable film, and a mask material is coated thereon,
In addition, a thick diamond film to serve as a backup grid is synthesized on it, and the second diamond film is selectively etched. This method will be described in detail with reference to FIG.

FIG. 2A shows a substrate 5 for forming a diamond film. As mentioned above, this is Si, M
o, W, SiC, SiN and the like. FIG. 2B shows a diamond thin film 6 to be a permeable film formed on the substrate 5 by a vapor phase synthesis method. Although it is a thin diamond film serving as a transmission film, it is possible to form a diamond thin film having a uniform thickness because the thin film is grown from 0 on the substrate instead of etching the thick film.

FIG. 2C shows a state in which the first mask 7 is coated on the diamond thin film 6. A mask metal is formed on the entire surface by vapor deposition and sputtering, and a necessary portion is left by photolithography and the other portions are removed. A mask 7 covers an opening, that is, a portion to be a transmission portion later. The part not covered with the mask 7 will later become a backup grid or the skeleton of the outer peripheral part.

Although the mask metal is selectively provided in this drawing, a mask metal layer may be formed on the entire diamond thin film 6 instead. In this case, the mask metal remains in the final product.

Any material can be used as the mask 7 as long as it can withstand etching and protect the diamond when the diamond is etched in a later step. Au, Ni, A
l, Si, Ti and the like are desirable as the mask material. If the mask 7 is too thin, a sufficient mask effect cannot be obtained. That is, the diamond directly below the mask cannot be protected during etching. On the other hand, if it is too thick, the adhesion between the upper and lower diamonds of the mask 7 becomes insufficient and the diamond film may be peeled off. If it is too thick, unnecessary fluorescent X-rays are generated from the mask, which lowers the detection limit. Therefore, the film thickness of the mask is preferably about 100 Å to 5000 Å.

FIG. 2D shows a state in which the diamond film 8 is vapor-phase synthesized on the mask 7 to a required thickness. This diamond film 8 will later become a backup grid. The diamond film 8 is formed to have the same thickness as the backup grid. A portion of the mask 7 is deposited on the mask 7. In the area without the mask 7, the first
It is formed directly on the diamond thin film 6 of the layer.

In FIG. 2 (e), a second mask 9 is formed on the diamond film 8 by a usual photolithography technique.
It shows a state in which is formed. The distribution of the mask 9 is determined reciprocally with respect to the mask 7 described above. That is, the mask 9 covers only the skeleton part of the outer peripheral part and the part which becomes the backup grid.

FIG. 2F shows a state where the diamond film 8 not covered with the mask 9 is selectively removed by etching from above the second mask 9. The portion that is not covered with the second mask 9 is a portion that should be a transparent portion. Since there is the first mask 7 below, the etching stops at this mask 7 and does not proceed further. The diamond thin film 6 to be the transmission part just below the mask 7 is not damaged, and the thickness is equal to the original thickness obtained by vapor phase synthesis in FIG. 2 (b). Since the first mask 7 protects the diamond film in the transparent portion, the etching speed and time can be controlled more easily. This is an advantage of the method of FIG.

After that, the second mask 9 and the first mask 7 exposed by the etching are removed. Furthermore, FIG.
By the same method as that shown in (e), the peripheral portions of the side and back surfaces of the substrate are covered with a resist, and the central portion of the substrate 1 is removed by etching.

FIG. 2 (g) shows this state. The diamond thin film 6 at the center is first formed in the process of FIG. Since this is not etched, the thickness does not change. It is easy to obtain the desired thickness. The diamond remaining in the center becomes the backup grid. The diamond remaining on the outer periphery becomes the outer skeleton. This method uses the same diamond, but since the diamond to be the transmission part and the diamond to be the backup grid or the skeleton are produced by different steps, it is easy to strictly control the thickness of the diamond in the transmission part.

There have been a number of X-ray window materials in which the transmission part and the backup grid are made of different materials. Since the thin transmission part and the backup grid have poor adhesion, they can be deformed or peeled off. I first mentioned that there is sex. In the present invention, the transmission part and the backup grid are formed in different steps, but since they are the same diamond, the adhesion is good and distortion due to the difference in the coefficient of thermal expansion does not occur.

If the X-ray window material is transparent, X
The photomultiplier tube of the line detector may pick up noise. This is because the disturbance visible light may enter the photomultiplier tube. In this case, it is better to coat the portion corresponding to the window with an extremely thin film of graphite, silicon, or other metal so that the light-transmitting property is lost. If the film thickness of the substance to be coated is too thin, a sufficient coloring effect to lose the light transmitting property cannot be obtained. If it is too thick, it will reduce the X-ray transmittance. Therefore, it is desirable that the thickness of the coating material for eliminating the translucency is about 30Å to 100Å.

The surface of the substrate on which the diamond is grown is mirror-polished due to the requirements of flatness and film thickness. To control the nucleation density when diamond grows on the substrate, 1
It is more preferable that the substrate surface is previously scratched with fine diamond abrasive grains of 0 μm or less and then mirror-polished. Since the nucleation of diamond is promoted by the scratch treatment, a uniform film can be formed.

The mask 7 shown in FIG. 2 also needs to have a uniform diamond film formed thereon. Therefore, after the mask 7 is coated, it is preferable to carry out a scratching treatment with diamond abrasive grains as in the case of the substrate.

[0047]

The X-ray window material produced by the method of the present invention is
A portion of the diamond thin film, which is an X-ray transmitting portion, which is thickly deposited on the diamond thin film is selectively etched and left as a backup grid. Therefore, it is easy to control the thickness of the backup grid, the thickness (width) of one crosspiece, the width of the opening, and the opening ratio.

In the manufacturing method of FIG. 1, the diamond thin film and the diamond backup grid are integrated. Therefore, there is no difference in stress between the thin film and the backup grid. Also, since diamond is formed as an integral unit from the beginning, the adhesion between the thin film and the backup grid is perfect.

In the manufacturing method of FIG. 2, metal is thinly sandwiched between the thin film and the backup grid. The inclusion of the metal layer relieves the stress difference between the thin film and the backup grid. The X-ray window material manufactured by any of the manufacturing methods has the same diamond to form the thin film and the backup grid, so that the adhesion is large and the thermal distortion is small. When used as an X-ray window material, it has a large strength against pressure difference between the inside and outside, and is an excellent window without leaks.

[0050]

EXAMPLE A mirror-polished surface of a 2-inch (100) single crystal silicon wafer having a thickness of 0.35 mm was scratched by using diamond abrasive grains. A 0.45 μm thick diamond thin film was formed on this by a known microwave plasma CVD method. The film was observed using a scanning microscope. A diamond film was formed on the entire wafer.
There was no part where the substrate was exposed. There was no pinhole either. It was a continuous film having a uniform film thickness.

Next, 0.1 μm of Ti was coated on this diamond thin film by a known vacuum deposition method.
The Ti film was scratched and treated by using diamond abrasive grains.
Further, a diamond having a thickness of 15 μm was formed thereon by a known filament CVD method.

After that, an Al mask was formed on this diamond film by ordinary photolithography. Al
The mask is shaped so as to cover the backup grid and the skeleton.

This was etched by a parallel plate type plasma etching device. The etching conditions are as follows.

Etching gas O ₂ + Ar mixed gas mixture ratio Ar / (O ₂ + Ar) = 1% Pressure 0.02 Torr High frequency power 100 W

As a result, the portion without the Al mask was removed by etching, and the lower Ti layer was exposed. The portion covered with the Al mask remains. This will be the backup grid. After this, the Ti exposed on the diamond thin film was replaced with C
Etching was performed by exposing to F ₄ plasma. This leaves only the diamond film on the upper surface.

The side surface and the peripheral portion of the lower surface of the substrate were covered with a resist, and the central portion of the substrate was removed by etching with a mixed solution of hydrofluoric acid and nitric acid. As a result, an X-ray window material having an aperture ratio of 82% for the X-ray transmitting portion was obtained.

[0057]

The method of the present invention is a method for producing an X-ray window material in which a diamond thin film is reinforced with a diamond backup grid. The transparent portion is diamond, and the reinforcing portion is also diamond. Since the transparent portion is diamond, it has excellent low-energy X-ray transmission characteristics.
Since the reinforcing portion is also made of diamond, there is no strain due to stress or stress due to temperature change. It is possible to provide an X-ray window material for an energy-dispersive X-ray microanalyzer, which has excellent transparency, durability, and pressure resistance and has a long life.

[Brief description of drawings]

FIG. 1 is a process diagram showing changes in the state of a substrate, a diamond film, a mask, etc. for explaining a method for manufacturing an X-ray window material of the present invention.

FIG. 2 is a process drawing showing changes in the state of a substrate, a diamond film, a mask, etc. for explaining a second method for manufacturing an X-ray window material of the present invention.

[Explanation of symbols]

 1 Substrate 2 Diamond Film 3 Mask 4 Resist 5 Substrate 6 Diamond Thin Film 7 Mask 8 Diamond Film 9 Mask

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[Procedure amendment]

[Submission date] June 17, 1994

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Title: X-ray window material and method for manufacturing the same

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[Document name to be amended] Statement

[Name of item to be amended] Claims

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[Correction content]

[Claims]

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

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[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray window material and a method for manufacturing the same. In recent years, analyzers using X-rays have come to be used in a very wide field of industrial technology. Its performance has also made great strides. There are various devices,
Utilizing its short wavelength and strong transparency, it is possible to quantitatively analyze the structure, composition, impurities, etc. of a substance.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

Among them, the energy dispersive X-ray microanalyzer has an advantage that a two-dimensional element distribution can be easily analyzed with a relatively high resolution. Therefore, it is widely used in the analysis of various substances. The present invention relates to an X-ray window material used as a partition between an X-ray detector and a sample chamber in an energy dispersive X-ray microanalyzer and a method for manufacturing the same.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] 0057

[Correction method] Change

[Correction content]

[0057]

The present invention provides an X-ray window material in which a diamond thin film is reinforced with a diamond backup grid. The transparent portion is diamond, and the reinforcing portion is also diamond. Since the transparent portion is diamond, it has excellent transmission characteristics for low-energy X-rays. Since the reinforcing portion is also made of diamond, there is no strain due to stress or stress due to temperature change. It is possible to provide an X-ray window material for an energy dispersive X-ray microanalyzer having excellent transparency, durability and pressure resistance and having a long life.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG. 1 is a process diagram showing changes in the state of a substrate, a diamond film, a mask, etc. for explaining the structure and manufacturing method of an X-ray window material of the present invention.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

FIG. 2 is a process diagram showing changes in the state of a substrate, a diamond film, a mask, etc. for explaining the structure and manufacturing method of a second X-ray window material of the present invention.

Claims (2)

[Claims] 1. A diamond thin film which remains thin after etching by selectively etching a diamond film synthesized by a vapor phase synthesis method on a substrate to a required thickness, removing a central portion of the substrate through which X-rays can pass. X-ray transmission part,
A method of manufacturing an X-ray window material, wherein a diamond portion left unetched is used as a backup grid. 2. A step of synthesizing a diamond thin film on a substrate by a vapor phase synthesis method, a step of coating a first mask such as a metal on the diamond thin film, and a vapor phase synthesis method on the mask. A step of synthesizing a diamond film by the above method, a step of forming a second mask on the diamond film so as to cover only a portion to be a backup grid, and a portion of the diamond film not covered by the second mask Of the first mask and the second mask exposed after the diamond etching
2. A method of manufacturing an X-ray window material, comprising: a step of etching the mask of 2);