JPH11233417A - X-ray mask and manufacturing method thereof - Google Patents

Abstract

(57) Abstract: Provided is an X-ray mask capable of obtaining a pattern having no defect and having high dimensional accuracy, and a method of manufacturing the same. After a membrane is formed on a surface of a substrate, the substrate is immersed in a solution capable of dissolving the substrate. Thereafter, a process for correcting the pit 2a is performed, and film formation and patterning of each film are performed.
The line mask 10 is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray mask and a method for manufacturing the same.

[0002]

2. Description of the Related Art Hitherto, a lithography technique using an ultraviolet ray has been mainly used for transferring a pattern in a semiconductor memory device having a relatively low degree of integration. However, as the degree of integration of semiconductor memory devices increases, for example, DRAM (Dyna
In the case of a Gbit class such as 1 Gbit (gigabit) in a mic random access memory (Mbit), each pattern such as a wiring becomes extremely fine according to a device rule, so that a pattern with higher resolution must be transferred.

As a technique for transferring such a fine pattern, a lithography technique using X-rays is expected. In this X-ray lithography technology, since the wavelength of the X-rays (soft X-rays: λ = 5 to 20 nm) serving as exposure light is shorter than that of ultraviolet light, it is possible to transfer a pattern with higher resolution than lithography using ultraviolet light. Become.

A conventional method of manufacturing an X-ray mask used in such an X-ray lithography technique will be described below.

FIGS. 11 to 16 are schematic sectional views showing a conventional method of manufacturing an X-ray mask in the order of steps. Referring to FIG. 11, a membrane 2 made of SIC is formed on both surfaces of a silicon substrate 1.

Referring to FIG. 12, a normal RIE (Reacti
A part of the membrane 2 on the back surface of the silicon substrate 1 is removed by a ve ion etching method.

Referring to FIG. 13, in this state, substrate 1 is immersed in a liquid capable of dissolving the material of substrate 1. Thereby, the substrate 1 is removed (back-etched) from the back surface side, and the back surface of the membrane 2 is exposed.

Referring to FIG. 14, an antireflection film 4, an X-ray absorber 5, and an etching mask 6 are formed on the surface of membrane 2 by sputtering. Then, a resist 7 is applied on the etching mask 6.

Referring to FIG. 15, after that, resist 7 is patterned, and etching is performed on etching mask 6 and X-ray absorber 5 using patterned resist pattern 7 as a mask. Thereby, the X-ray absorber 5 is patterned. After that, the resist pattern 7
And the etching mask 6 are removed to complete the X-ray mask 110 shown in FIG.

[0010]

In the conventional method of manufacturing an X-ray mask, even if pits (through holes) are formed in the membrane 2, they cannot be found. However, there was a problem that it could not be formed. Hereinafter, this will be described.

Usually, at the time of film formation of the membrane 2, FIG.
As shown in (1), the foreign matter 100 in the film forming apparatus is taken into the membrane 2. If the surface of the membrane 2 has irregularities, the characteristics of the X-ray absorber 4 (FIG. 14) formed in a later step deteriorate. For this reason, it is necessary to flatten the surface of the membrane 2 by polishing or the like. However, during this flattening process, foreign matter 100 in the membrane 2 is detached, and pits 2a are generated in the membrane 2 as shown in FIG.

The membrane 2 is transparent to X-rays and transparent to visible light. For this reason, it was not possible to visually detect that pits 2a were formed in the membrane 2. FIG. 19 with the pit 2a generated
When the films 4, 5, and 6 are formed by the sputtering method as shown in (1), the films 4, 5, and 6 are not formed on the pit 2a. Therefore, when the X-ray absorber 5 is patterned using the resist pattern 7 and the etching mask 6 as shown in FIG. 20, the presence of the pits 2a as shown in FIG.
The X-ray absorber 5 no longer exists in the region R where the pattern of the X-ray absorber 5 should originally exist, resulting in a pattern defect. As a result, an area that should not be exposed on the wafer is exposed, so that the wafer cannot be patterned into a desired shape and transfer defects occur.

On the other hand, as shown in FIG. 22, there may be a case where the pit 2a is located in a region where the pattern of the X-ray absorber 5 is not originally formed. In this case, as shown in FIG. 23A, even in the same exposure area, the X-ray intensity of the transmitted light is different between the exposure area without the pit 2a and the exposure area with the pit 2a. That is, the intensity of the X-rays passing through the path of arrow A is different from the intensity of the X-rays passing through the path of arrow B.

In the X-rays passing through the path indicated by the arrow A, the intensity of the transmitted light of the X-rays is attenuated to about 50% with respect to the incident light as shown in FIG. On the other hand, the intensity of the transmitted light remains at 100% for the X-rays passing through the path indicated by arrow B. For this reason, the distribution range of the intensity that causes the photochemical reaction of the resist on the wafer is wider for the X-rays passing through the arrow B path than for the X-rays passing the arrow A path. Therefore, as shown in FIG. 23C, in the portion of the resist 52 on the wafer 51 where the X-ray has passed through the path of the arrow B, the pattern is wider than the set dimension L, and the dimensional accuracy of the pattern Deteriorates.

An X-ray mask that cannot form a desired pattern as described above is regarded as a defective product. For this reason, the occurrence of the pits 2a has been a major factor in lowering the yield of X-ray mask production.

Therefore, it is an object of the present invention to be free of defects,
An object of the present invention is to provide an X-ray mask capable of obtaining a pattern having a wide dimensional accuracy and a method of manufacturing the same.

[0017]

According to the present invention, there is provided an X-ray mask comprising:
It has a membrane, a buried layer, and an X-ray absorber.
The membrane is made of a material that transmits X-rays and has a through hole. The buried layer embeds the through-hole and has substantially the same transmittance as the membrane. The X-ray absorber is
It is made of a material that blocks transmission of X-rays, and is patterned on the membrane.

In the X-ray mask of the present invention, a buried layer having substantially the same transmittance as that of the membrane is buried in the through-hole.
Deterioration of the dimensional accuracy of the pattern can be prevented, and the yield can be improved.

Preferably, in the above-mentioned X-ray mask, an antireflection film made of a material for preventing reflection of alignment light is further provided between the membrane and the X-ray absorber.

Thus, the reflection of the alignment light can be prevented. The method for manufacturing an X-ray mask of the present invention is based on X
A method for manufacturing an X-ray mask having a patterned X-ray absorber made of a material that blocks transmission of X-rays on a membrane made of a material that transmits X-rays, comprising the following steps.

First, a membrane is formed on the main surface of the substrate. Then, a process for removing the material of the substrate is performed on the substrate on which the membrane is formed, and it is determined whether or not the membrane has a through hole.

In the method of manufacturing an X-ray mask according to the present invention, a process capable of removing the material of the substrate is performed. Thus, if the membrane has a through-hole, a predetermined amount of the main surface of the substrate exposed in the through-hole is removed by the above-described processing, and a groove is formed on the main surface of the substrate. This substrate does not need to be transparent to visible light because it does not need to be transparent to X-rays like a membrane. Therefore, when a groove is formed in the substrate, the groove can be found visually. By making the groove discoverable in this way, if the substrate has a groove, the membrane has a through hole, and if there is no groove, the membrane has no through hole. . That is, it is possible to determine whether or not the membrane has a through hole.

If it is known that the membrane has a through hole, the through hole can be corrected. If the through holes are corrected, it is possible to prevent the occurrence of pattern defects and the deterioration of the dimensional accuracy of the patterns due to the presence of the through holes. As described above, a product which should be a defective product by correcting the through-hole can be made a good product, so that the yield can be improved.

In the above method of manufacturing an X-ray mask, preferably, when it is determined that the membrane has a through hole, a polymer film is formed on the entire surface of the membrane so as to fill the through hole. Then, a part of the polymer film is removed so that the embedded layer having the polymer film remains in the through hole.

As a result, it is possible to bury the through-hole of the membrane, thereby preventing the occurrence of pattern defects and the deterioration of the dimensional accuracy of the pattern.

In the above method of manufacturing an X-ray mask, preferably, when it is determined that the membrane has a through-hole, the through-hole is irradiated with a focused ion beam to selectively bury the embedded layer in the through-hole. The step of embedding is further provided.

[0027] Thereby, the through-hole of the membrane can be buried, and the occurrence of pattern defects and the deterioration of the dimensional accuracy of the pattern can be prevented.

In the above method of manufacturing an X-ray mask, preferably, when it is determined that the membrane has a through-hole, a solution reservoir is brought into contact with the through-hole and liquid phase epitaxial growth is performed to allow the inside of the through-hole to be formed. Is embedded in the burying layer.

As a result, it is possible to bury the through-hole of the membrane, thereby preventing the occurrence of pattern defects and the deterioration of the dimensional accuracy of the pattern.

In the above-described method for manufacturing an X-ray mask, preferably, the buried layer in the through hole has substantially the same X-ray transmittance as that of the membrane.

As a result, it is possible to prevent the occurrence of pattern defects and the deterioration of the dimensional accuracy of the pattern.

Preferably, the above method of manufacturing an X-ray mask further comprises a step of polishing the surface of the membrane after forming the buried layer.

Thus, the surface of the membrane can be flattened.

[0034]

Embodiments of the present invention will be described below with reference to the drawings.

First Embodiment FIGS. 1 to 8 are schematic sectional views showing a method of manufacturing an X-ray mask according to a first embodiment of the present invention in the order of steps. Referring to FIG. 1, a membrane 2 made of, for example, SiC is formed on both surfaces of a front surface and a back surface of a substrate 1 made of, for example, silicon. At this point, pits 2a may be formed on the membrane 2 due to foreign substances or the like during the film formation of the membrane 2 described above.

Referring to FIG. 2, substrate 1 is immersed in a solution 11 capable of dissolving the material of substrate 1 (for example, a hydrofluoric nitric acid solution) with membrane 2 formed thereon. At this time, if there are pits 2a in the membrane 2, the surface of the substrate 1 exposed from the pits 2a is removed by the solution 11, and the grooves 1a are removed.
Is formed.

Referring to FIG. 3, since the membrane 2 is transparent to visible light, the pits 2
a cannot be found visually. However, since the silicon substrate 1 is not transparent to visible light, the grooves 1a formed in the silicon substrate 1 can be found visually. Therefore, when the groove 1a is visually found, the polymer film 3 is formed on the entire surface of the membrane 2 so as to fill the groove 1a and the pit 2a.

As the material of the polymer film 3, for example, novolak resin, epoxy resin, polyimide, polyethylene, polystyrene, acrylic resin, polyacetal,
Polyvinyl acetate, polyvinyl alcohol and the like are used. Thereafter, etch back or polishing is performed on the entire surface of the polymer film 3 until the surface of the membrane 2 is exposed.

Referring to FIG. 4, by this etch back and polishing, the polymer film 3 is left so as to fill only the pits 2 a and the grooves 1 a of the substrate 1, and becomes a buried layer 3.
Thereafter, R is placed on the center of the membrane 2 on the back surface of the substrate 1.
IE is performed, and the membrane 2 is selectively removed.

Referring to FIG. 5, in this state, substrate 1 is immersed in a liquid capable of dissolving the material of substrate 1 (for example, a hydrofluoric nitric acid solution). As a result, the substrate 1 is removed (back-etched) from the back side.

Referring to FIG. 6, after that, on the surface of the membrane 2, an antireflection film 4 made of, for example, indium / tin oxide, and an X made of, for example, a tantalum-based material are formed.
A line absorber 5 and an etch mask 6 made of, for example, tungsten are sequentially formed by sputtering.

Referring to FIG. 7, resist 7 is applied on etch mask 6 and baked. Then, after a pattern is drawn on the resist 7 by an electron beam writer (EB), it is developed to form a resist pattern 7. Etching is performed on etch mask 6 using resist pattern 7. Thereafter, the X-ray absorber 5 is etched using the patterned etch mask 6, and the X-ray absorber 5 is patterned. Finally, resist pattern 7
Then, the etch mask 6 is removed, and the X-ray mask 10 shown in FIG. 8 is completed.

In the present embodiment, the substrate 1 is immersed in a solution 11 capable of dissolving the material of the substrate 1 in the step shown in FIG. As a result, when the membrane 2 has the pits 2a, the main surface of the substrate 1 exposed through the pits 2a is removed by the solution 11 by a predetermined amount, and the grooves 1a are formed on the main surface of the substrate. Since the substrate 1 does not need to be transparent to X-rays, if the groove 1a is formed in the substrate 1, the presence of the groove 1a can be visually confirmed. By making the groove 1a discoverable in this way, it can be seen that when the substrate 1 has the groove 1a, the pit 2a is formed in the membrane 2 and when there is no groove 1a, the pit 2a is formed in the membrane 2. It can be seen that it has not occurred. That is, it is possible to determine whether or not the membrane 2 has the pit 2a.

If it is found that the membrane 2 has the pit 2a, the pit 2a can be corrected.
In the present embodiment, in the steps shown in FIGS. 3 and 4, after forming the polymer film 3 on the entire surface so as to bury the pits 2a, the entire surface of the polymer film 3 is etched back or polished. Thus, the polymer film 3 remains only in the pit 2a.

Since the pits 2a can be buried in the buried layer 3 such as a polymer film, when the films 4, 5, and 6 are formed on the membrane 2 as shown in FIG. Each of the films 4, 5, and 6 is well deposited on 2a. For this reason, the occurrence of pattern loss is prevented.

The pits 2a are formed in a buried layer 3 such as a polymer film.
Embedded by For this reason, when X-rays are transmitted through the completed X-ray mask 10 in FIG. 8, the buried layer 3 reduces the intensity of the X-rays transmitted through the pits 2a by the intensity of the X-rays transmitted through other exposure regions. And can be adjusted substantially the same. Therefore, it is also possible to prevent the dimensional accuracy of the pattern from deteriorating due to the high intensity of the transmitted light in the pit 2a.

In this embodiment, pit 2
The case where a polymer film is used as a method for correcting a has been described. In addition, FIB (Focused Ion Beam)
The correction may be performed by the LPE (Liquid Phase Epitaxy) method. Hereinafter, a correction method using the FIB method will be described in a second embodiment, and a correction method using the LPE method will be described in a third embodiment.

Embodiment 2 FIG. 9 is a schematic sectional view showing a method for manufacturing an X-ray mask according to Embodiment 2 of the present invention.

In this embodiment, the pits are corrected by the FIB method as described above. The manufacturing method of the present embodiment first includes the steps of Embodiment 1 shown in FIGS. Thereafter, as shown in FIG. 9, the buried layer 3 is selectively formed in the pit 2a by irradiating the focused ion beam to the pit 2a.

The material and thickness of the buried layer 3 are determined so that the X-ray transmittance of the buried layer 3 formed by the FIB method is equal to the X-ray transmittance of the membrane 2 at the uncorrected portion. . Here, if the X-ray transmittance of the material of the buried layer 3 is Uf, the film thickness is T, and the X-ray transmittance of the material of the membrane 2 is Um, and the film thickness is t, Uf × T = Um × t. The material and thickness of the buried layer 3 and the membrane 2 are determined as described above. As a material of the buried layer 3, for example, C (carbon), Ga (gallium), In (indium),
Sn (tin), B (boron), As (arsenic) and the like are used.

Thereafter, through the same steps as in the first embodiment shown in FIGS. 5 to 8, the X-ray mask 10 is completed.

Third Embodiment FIG. 10 is a schematic sectional view showing a method for manufacturing an X-ray mask according to a third embodiment of the present invention.

In this embodiment, the pits are corrected by the LPE method as described above. The manufacturing method of the present embodiment goes through the same steps as those of the first embodiment shown in FIGS. After that, as shown in FIG. 10, the buried layer 3 is formed in the pit 2a by dissolving the metal solution 12 stored in the molten pool of the graphite boat 13 into the pit 2a and cooling it.

According to this method, the buried layer 3 can be selectively formed in the pit 2a and the graphite boat 13
If you slide in the horizontal direction as shown by the arrow, pit 2
A film can be formed on the entire surface of the membrane 2 as well as in the area a. When a film is formed on the entire surface of the membrane 2, similarly to the first embodiment shown in FIGS. 3 and 4, the entire surface of the film is etched back or polished so as to be embedded only in the pit 2a. Layer 3 can be left.

The material of the buried layer 3 manufactured by the LPE method includes, for example, Zn (zinc), Al (aluminum), Ge (germanium), Mg (magnesium), Ga (gallium), In (indium), Sn
(Tin) or the like is used.

Thereafter, through the same steps as in the first embodiment shown in FIGS. 5 to 8, the X-ray mask 10 is completed.

In the second and third embodiments, even when buried layer 3 is selectively formed only in pit 2a,
Preferably, the surface of the membrane 2 is subjected to a surface flattening treatment such as polishing. Thereby, the characteristics of the X-ray absorber 5 formed on the upper layer are improved.

In the first to third embodiments, the grooves 1a are formed in the substrate 1 by immersing the substrate 1 in the solution 11, as shown in FIG. However, the method of forming the groove 1a is not limited to this method, and another method such as dry etching may be used.

The embodiments disclosed this time are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[0060]

According to the X-ray mask of the present invention, a buried layer having substantially the same transmittance as that of the membrane is buried in the through-hole. Deterioration of dimensional accuracy can be prevented, and yield can be improved.

Preferably, in the above-mentioned X-ray mask, an antireflection film made of a material for preventing reflection of alignment light is further provided between the membrane and the X-ray absorber.

Thus, the reflection of the alignment light can be prevented. In the method of manufacturing an X-ray mask according to the present invention, a process capable of removing the material of the substrate is performed. Thus, if the membrane has a through-hole, a predetermined amount of the main surface of the substrate exposed in the through-hole is removed by the above-described processing, and a groove is formed on the main surface of the substrate. This substrate does not need to be transparent to visible light because it does not need to be transparent to X-rays like a membrane. Therefore, when a groove is formed in the substrate, the groove can be found visually. By making the groove discoverable in this way, if the substrate has a groove, the membrane has a through hole, and if there is no groove, the membrane has no through hole. . That is, it is possible to determine whether or not the membrane has a through hole.

If it is found that the membrane has a through-hole, the through-hole can be corrected. If the through holes are corrected, it is possible to prevent the occurrence of pattern defects and the deterioration of the dimensional accuracy of the patterns due to the presence of the through holes. As described above, a product which should be a defective product by correcting the through-hole can be made a good product, so that the yield can be improved.

In the above method of manufacturing an X-ray mask, preferably, when it is determined that the membrane has a through hole, a polymer film is formed on the entire surface of the membrane so as to fill the through hole. Then, a part of the polymer film is removed so that the embedded layer having the polymer film remains in the through hole.

As a result, it is possible to bury the through-holes of the membrane, and it is possible to prevent occurrence of pattern defects and deterioration of dimensional accuracy of the pattern.

In the above method of manufacturing an X-ray mask, preferably, when it is determined that the membrane has the through hole, the focused ion beam is irradiated to the through hole to selectively embed the hole in the through hole. There is further provided the step of embedding the layer.

As a result, it is possible to bury the through-hole of the membrane, and it is possible to prevent the occurrence of pattern defects and the deterioration of the dimensional accuracy of the pattern.

In the above method of manufacturing an X-ray mask, preferably, when it is determined that there is a through-hole in the membrane, a solution reservoir is brought into contact with the through-hole and liquid phase epitaxial growth is carried out to make the inside of the through-hole. Is embedded in the burying layer.

As a result, the through holes of the membrane can be buried, and the occurrence of pattern defects and the deterioration of the dimensional accuracy of the pattern can be prevented.

In the above method of manufacturing an X-ray mask, preferably, the buried layer in the through hole has substantially the same X-ray transmittance as that of the membrane.

As a result, it is possible to prevent the occurrence of pattern defects and the deterioration of pattern dimensional accuracy.

Preferably, the above method of manufacturing an X-ray mask further comprises a step of polishing the surface of the membrane after forming the buried layer.

As a result, the surface of the membrane can be flattened.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a first step of a method for manufacturing an X-ray mask according to Embodiment 1 of the present invention.

FIG. 2 is a schematic cross-sectional view showing a second step of the method for manufacturing an X-ray mask according to the first embodiment of the present invention.

FIG. 3 is a schematic sectional view showing a third step of the method for manufacturing an X-ray mask according to the first embodiment of the present invention.

FIG. 4 is a schematic sectional view showing a fourth step of the method of manufacturing the X-ray mask according to the first embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view showing a fifth step of the method for manufacturing an X-ray mask according to the first embodiment of the present invention.

FIG. 6 is a schematic cross-sectional view showing a sixth step of the method for manufacturing an X-ray mask according to the first embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view showing a seventh step of the method for manufacturing an X-ray mask according to the first embodiment of the present invention.

FIG. 8 is a schematic cross-sectional view showing an eighth step of the method for manufacturing an X-ray mask according to the first embodiment of the present invention.

FIG. 9 is a schematic sectional view illustrating a method for manufacturing an X-ray mask according to Embodiment 2 of the present invention.

FIG. 10 is a schematic sectional view illustrating a method for manufacturing an X-ray mask according to Embodiment 3 of the present invention.

FIG. 11 is a schematic sectional view showing a first step of a conventional method for manufacturing an X-ray mask.

FIG. 12 is a schematic cross-sectional view showing a second step of the conventional method for manufacturing an X-ray mask.

FIG. 13 is a schematic sectional view showing a third step of the conventional method for manufacturing an X-ray mask.

FIG. 14 is a schematic sectional view showing a fourth step of the conventional method for manufacturing an X-ray mask.

FIG. 15 is a schematic cross-sectional view showing a fifth step of the conventional method for manufacturing an X-ray mask.

FIG. 16 is a schematic cross-sectional view showing a sixth step of the conventional method for manufacturing an X-ray mask.

FIG. 17 is a first process diagram showing a state in which pits are formed on the membrane.

FIG. 18 is a second process diagram illustrating a state in which pits are formed on the membrane.

FIG. 19 is a first process diagram for describing a problem that occurs when a pit occurs in the membrane.

FIG. 20 is a second process diagram for describing a problem that occurs when a pit occurs in the membrane.

FIG. 21 is a third process diagram for describing a problem that occurs when a pit occurs in the membrane.

FIG. 22 is a schematic cross-sectional view for describing a problem that occurs when a pit occurs in the membrane.

FIG. 23 is a diagram for explaining that the dimensional accuracy of the pattern differs between a portion having pits and a portion having no pits in the transmission region.

[Explanation of symbols]

1 substrate, 2 membranes, 2a pits, 3 buried layer, 4 anti-reflection film, 5 X-ray absorber, 10 X-ray mask.

Claims (8)

[Claims] 1. A membrane made of a material that transmits X-rays and having a through-hole, an embedding layer embedded in the through-hole and having substantially the same transmittance as the membrane, and blocking transmission of X-rays. An X-ray mask comprising an X-ray absorber made of a material and patterned on the membrane. 2. The X-ray detector according to claim 1, further comprising an antireflection film made of a material for preventing reflection of alignment light, between the membrane and the X-ray absorber.
Line mask. 3. A method for manufacturing an X-ray mask having a patterned X-ray absorber made of a material that blocks transmission of X-rays on a membrane made of a material that transmits X-rays, comprising: a main surface of a substrate; A step of forming the membrane, and a step of subjecting the substrate on which the membrane is formed to a process capable of removing a material of the substrate, and determining whether or not the membrane has a through-hole. , X-ray mask manufacturing method. 4. When it is determined that the through hole is present in the membrane, a step of forming a polymer film on the entire surface of the membrane so as to fill the inside of the through hole; 4. The method of manufacturing an X-ray mask according to claim 3, further comprising: removing a part of the polymer film so that the buried layer having the polymer film remains. 5. A step of selectively embedding a buried layer in the through-hole by irradiating the through-hole with a focused ion beam when it is determined that the membrane has the through-hole. Equipped,
A method for manufacturing an X-ray mask according to claim 3. 6. When it is determined that the through hole is present in the membrane, a solution reservoir is brought into contact with the through hole to perform liquid phase epitaxial growth, so that the inside of the through hole is filled with a buried layer. The method for manufacturing an X-ray mask according to claim 3, further comprising a step of embedding. 7. The method of manufacturing an X-ray mask according to claim 4, wherein the buried layer in the through-hole has substantially the same X-ray transmittance as the membrane. Method. 8. The method according to claim 4, further comprising the step of polishing the surface of said membrane after forming said buried layer.
The method for manufacturing an X-ray mask according to any one of the above.