Silicon-based bender monochromator based on concave glass press bending and anodic bonding and preparation method thereof

Abstract

This invention discloses a method for fabricating silicon-based bent crystal monochromators based on concave glass bending and anodic bonding, belonging to the field of X-ray optical device fabrication technology. This invention achieves silicon wafer shaping through precise surface constraint of the concave glass, and then achieves atomic-level permanent bonding through anodic bonding, fundamentally eliminating the stress relaxation problem of traditional mechanical bending methods. The surface accuracy of the device can remain stable for more than 10 years, and its high-temperature resistance is significantly improved compared to traditional epoxy resin bonding methods. The process flow of this invention is simple and controllable, compatible with existing semiconductor wafer processing technologies, and can fabricate large-size bent crystal devices with high yield, suitable for mass production. This invention has extremely high flexibility; by simply adjusting the radius of curvature of the concave glass and the crystal orientation of the silicon wafer, bent crystal monochromators with different focal lengths and diffraction properties can be fabricated, making it fully adaptable to various application scenarios from laboratory X-ray equipment to synchrotron radiation sources.

Description

Technical Field

[0001] This invention belongs to the field of X-ray optical device fabrication technology, specifically relating to a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding and its fabrication method, applicable to the large-scale fabrication of silicon-based bent crystal monochromators in fields such as synchrotron radiation sources, laboratory X-ray diffractometers, X-ray fluorescence spectrometers, and X-ray imaging equipment. Background Technology

[0002] Curved crystal monochromators are core functional devices in X-ray spectroscopy analysis, diffraction imaging, and materials characterization. Their core function is to separate and monochromate incident multicolor X-rays, while also having a focusing function, which greatly improves the utilization efficiency and spectral resolution of X-rays.

[0003] Currently, the mainstream fabrication technologies for silicon-based bent monochromators fall into two main categories: the first is the mechanical bending method, which involves bending a planar single-crystal silicon wafer to the target curvature using a specialized fixture, and then fixing it with a mechanical structure. This method is simple, but it has fatal flaws: first, the mechanical clamping only involves point / line contact fixation, and the internal stress of the silicon wafer is prone to relaxation over time, temperature, and vibration, leading to a significant decrease in the device's shape accuracy and optical performance degradation after long-term use; second, there is a gap between the bent silicon wafer and the supporting structure, causing X-ray scattering and loss, reducing the spectral efficiency; and third, the device has poor resistance to vibration and temperature shock, making it unsuitable for high-precision, high-stability applications such as synchrotron radiation sources.

[0004] The second type is the curved surface epitaxial growth method, which grows single-crystal Si thin films on a pre-formed curved substrate using processes such as molecular beam epitaxy and chemical vapor deposition. This method can produce high-quality curved single crystals, but it suffers from drawbacks such as extremely high process costs, large equipment investment, difficulty in controlling the thickness and crystal orientation of the single-crystal film, and difficulty in producing large-size curved crystals, thus making it impossible to achieve large-scale mass production.

[0005] Anodizing is a process that enables atomic-level permanent bonding between silicon and glass, widely used in MEMS devices and semiconductor packaging. However, in current technologies, anodic bonding is mostly applied to bonding planar structures between planar silicon and glass, rarely combined with the elastic bending process of silicon wafers. This is because the prerequisite for planar silicon-glass anodic bonding is that the two materials have already achieved large-area, uniform, and close contact before heating and applying electricity; curved bonding naturally disrupts this prerequisite. Comparing planar glass and curved glass, they have at least the following differences: First, the initial contact conditions between curved glass and non-planar glass are completely different from those of curved silicon wafers: curved silicon wafers cannot naturally adhere to curved glass. In contrast, when bonding planar silicon wafers to planar glass, as long as the surfaces are sufficiently flat and clean, almost full contact can be easily formed under external force. The anodic bonding process proceeds smoothly, and the bonding interface gradually expands from a local area to the entire surface. This is a crucial characteristic of planar anodic bonding: the bonding front propagates spontaneously. However, silicon wafers are rigid and initially planar. If the glass is non-planar, without bending the silicon wafer, only a local area (usually the center or edge) will be in contact, with significant air gaps in the remaining areas. These gaps prevent the electric field from being uniformly established, directly causing anodic bonding to fail to expand spontaneously like on a planar surface. This results in bonding occurring only in the initial contact area and failing to extend to the entire curved surface.

[0006] Secondly, silicon is a typical brittle material. Forcibly bending a flat silicon wafer into a curved silicon wafer will generate significant bending stress. If planar processes are used directly, problems such as wafer cracking, local warping, high residual stress after bonding, and cracking or debonding after cooling may occur.

[0007] Finally, during planar bonding, air at the interface is easily expelled from the edges, while the problem of gas retention between curved surfaces is more serious. When the bonding is not tight, air will form a closed cavity at the interface, which will cause the gas to expand after heating, further hindering the contact and forming more local unbonded areas.

[0008] Therefore, the key to curved surface bonding is to first achieve reliable curved surface bonding before performing anodic bonding. Furthermore, the temperature, voltage, and other parameters used for planar and curved anodic bonding cannot be the same. Curved surface bonding involves an additional mechanical process of "elastic bending and bonding of the silicon wafer" compared to planar bonding. Therefore, the electric field and temperature not only drive chemical bonding but also help maintain the bent contact state. Thus, curved surface bonding, in addition to completing the interfacial chemical reaction, must also overcome the springback force of the silicon wafer, which means the process window will change, requiring further parameter optimization.

[0009] Therefore, it is not feasible to directly use planar processes to fabricate curved crystals. Thus, developing a simple, high-precision, structurally stable, and cost-effective method for fabricating silicon-based curved crystal monochromators has become a pressing technical problem to be solved in this field. Summary of the Invention

[0010] To address the aforementioned deficiencies and shortcomings of existing technologies, the present invention aims to provide a silicon-based bent monochromator based on concave glass bending and anodic bonding, and its fabrication method. This method integrates the elastic bending of the silicon wafer with permanent anodic bonding, completely solving the problems of stress relaxation, poor surface accuracy, and poor interface bonding in traditional mechanical bending methods. At the same time, it significantly reduces the fabrication cost, improves device yield and optical performance, and meets the needs of large-scale production.

[0011] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of this invention is to provide a method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding, comprising the following steps: Provide open containers; According to the curvature requirements of the target bent crystal, a concave glass substrate with a preset curvature radius is prepared. The concave surface is then subjected to ultra-precision polishing to achieve the target surface shape accuracy and surface roughness. Subsequently, a rigorous cleaning process is performed to remove surface impurities and contaminants. The concave glass substrate with the preset curvature radius is then placed in an open container. Select a monocrystalline silicon wafer that matches the size of the concave glass substrate, and perform precision polishing on the bonding surface of the monocrystalline silicon wafer. Then, perform cleaning and surface activation treatments in sequence to remove the surface oxide layer and organic contaminants, thereby improving the bonding force of the bonding interface. The bonding surface of the pre-treated single-crystal silicon wafer is aligned with the concave surface of the concave glass substrate to complete coaxial alignment and bonding. A plastic film is placed on top of an open container, forming a sealed cavity with the container. A container lid is placed above the plastic film, with an inflation port in the center. The side wall of the open container is provided with an air extraction hole for evacuating the sealed cavity. The sealed cavity is evacuated through the air extraction hole, and gas is injected into the space formed by the container lid and the plastic film through the inflation port, so that the pressure in the space reaches the preset bonding pressure. Under the action of the pressure difference on both sides of the plastic film, the plastic film bends downward and transmits the pressure to the surface of the monocrystalline silicon wafer, causing the monocrystalline silicon wafer to undergo elastic deformation and completely conform to the concave curved surface contour of the concave glass substrate without interface gaps, thus obtaining a bonded assembly. A concave glass substrate and a single-crystal silicon wafer are connected to the negative and positive electrodes of an anodic bonding device, respectively. The bonding environment is preferably a vacuum environment to avoid interface oxidation. Anodic bonding is performed using the anodic bonding device at a preset bonding temperature, bonding voltage, and bonding pressure, forming a permanently integrated structure with atomic-level bonding. After post-processing, a silicon-based bent crystal monochromator is obtained. Further, the post-processing method involves laser cutting the integrated bent crystal substrate according to the size requirements of the target device, followed by edge grinding and chamfering. Finally, the diffraction surface of the silicon single crystal is subjected to ultra-precision polishing to achieve the target optical specifications, thus producing the silicon-based bent crystal monochromator.

[0012] As a preferred technical solution, the concave glass substrate is made of high borosilicate glass. This glass material has a high coefficient of thermal expansion matching with single-crystal silicon, effectively reducing thermal stress during the bonding process. The radius of curvature of the concave glass substrate can be flexibly adjusted according to the focal length and diffraction requirements of the target bent crystal, with a preferred range of 0.5 m to 2 m. The surface shape accuracy (PV value) of the concave surface is ≤1 μm, and the surface roughness (Ra) is ≤0.5 nm, ensuring the surface shape accuracy after the silicon wafer is bent. Before use, the concave glass substrate is ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water. After cleaning, it is dried with nitrogen and then vacuum-dried.

[0013] As a preferred technical solution, the single-crystal silicon wafer is an N-type or P-type wafer that is polished on one side. <100> , <111> or <110> The wafer is a crystal-oriented single-crystal silicon wafer with a thickness of 100 μm to 1000 μm and a surface roughness Ra ≤ 0.3 nm on the polished surface. The surface activation treatment is oxygen plasma treatment, argon ion sputtering treatment, or hydrofluoric acid wet etching treatment.

[0014] As a preferred technical solution, the bonding pressure is 0.1 MPa to 3 MPa, and the bonding holding time is 5 min to 10 min. The bonding pressure can be controlled by adjusting the volume of gas entering the inflation port; too low a pressure will result in incomplete bonding, while too high a pressure will cause edge cracking. The bonding holding time is 5 min to 10 min; too short a holding time will result in incomplete bonding, while too long a holding time will increase residual stress.

[0015] As a preferred technical solution, the bonding temperature is 360-410 °C. To facilitate heating, a heater is placed inside the open container, located at the bottom of the concave glass substrate. If the temperature is too low, ion migration is too slow; if the temperature is too high, the glass will soften, and residual stress will increase.

[0016] As a preferred technical solution, the bonding voltage is 800 V~1000 V. If the voltage is too low, the electric field is insufficient and the contact area cannot expand quickly. If the voltage is too high, it may break down the silicon wafer.

[0017] A second aspect of the present invention is to provide a silicon-based bent crystal monochromator, which is prepared by the fabrication method described in the first aspect above; the silicon-based bent crystal monochromator includes a concave glass substrate and a single-crystal silicon wafer permanently bonded to the concave surface of the concave glass substrate by anodic bonding. The surface shape accuracy PV value of the diffraction surface is ≤2 μm, and the surface roughness Ra is ≤0.5 nm.

[0018] Compared with the prior art, the present invention has the following significant advantages: 1. This invention is the first to integrate the elastic bending and shaping of silicon wafers with permanent anodic bonding. The silicon wafer is shaped by the precise curvature constraint of the concave glass, and atomic-level permanent bonding is achieved through anodic bonding. This fundamentally eliminates the stress relaxation problem of traditional mechanical bending methods. The surface accuracy of the device can be stable for more than 10 years. The high temperature resistance is improved from 100 ℃ to 400 ℃ compared with the traditional epoxy resin bonding method. The glass may soften above 400 ℃.

[0019] 2. This invention achieves a gapless, tight bond between silicon and glass by simultaneously performing elastic bending of silicon wafers and anodic bonding technology. Bending performance tests show that this bent monochromator successfully diffracts a monochromatic X-ray beam with concentrated energy and a clear outline. Its diffraction efficiency, focusing performance, and beam uniformity are all excellent, and the system exhibits a high signal-to-noise ratio and low background noise.

[0020] 3. The process of this invention is simple and controllable, does not require expensive epitaxial growth equipment, is compatible with existing semiconductor wafer processing technology, can fabricate large-size curved crystal devices, and has a fabrication cost of less than 1 / 10 of the traditional curved surface epitaxial method. It has a high yield and is suitable for mass production.

[0021] 4. This invention has extremely high flexibility. By simply adjusting the radius of curvature of the concave glass and the crystal orientation of the silicon wafer, curved crystal monochromators with different focal lengths and diffraction properties can be prepared, which can be fully adapted to various application scenarios from laboratory X-ray equipment to synchrotron radiation sources. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the apparatus used to fabricate the silicon-based bent crystal monochromator of the present invention. Figure 2 This is a schematic diagram illustrating the state changes between the concave glass substrate and the single-crystal silicon wafer in the preparation method of this invention; Figure 3 A photograph of the product prepared in Example 1; Figure 4 The performance test results are for the silicon-based bent crystal monochromator prepared in Example 1; Figure 5 This is a verification diagram showing the consistency between the benchtop X-ray absorption spectrum produced using the bent crystal monochromator prepared in this invention and the X-ray absorption test results of Zn elemental by a synchrotron radiation source. Figure 6 A photograph of the product prepared for Comparative Example 1; Figure 7 A photograph of the product prepared for Comparative Example 3.

[0023] Figure reference numerals: 1-Monocrystalline silicon wafer; 2-Concave glass substrate; 3-Lamination assembly; 4-Schematic diagram of anode bonding and positive and negative electrode directions; 5-Ejection hole; 6-Positive electrode; 7-Heater; 8-Inflation port; 9-Container lid; 10-Open container; 11-Plastic film; 12-Negative electrode; 13-Sealed cavity. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments are not intended to limit the present invention. In addition, unless otherwise specified, the preparation processes in the following embodiments are all conventional methods in the prior art, and therefore will not be described in detail.

[0025] The plastic film used in this invention is a flexible material that can withstand temperatures above 400°C. The polyimide film (PI film) used in the embodiments of this invention has high mechanical strength, high temperature resistance and high pressure resistance, and is also radiation resistant, aging resistant and can be used for a long time.

[0026] Figure 1 This is a schematic diagram of the apparatus used to fabricate the silicon-based bent crystal monochromator of the present invention. It comprises an open container 10, with a plastic film 11 placed on top of the container, forming a sealed cavity 13. A container lid 9 is placed above the plastic film, with an inflation port 8 in the center. The side wall of the open container 10 has an evacuation hole 5 for evacuating the sealed cavity 13. A heater 7 is placed inside the open container to facilitate heating. A concave glass substrate 2 is placed on the heater, and a single-crystal silicon wafer 1 is placed on top of the concave glass substrate 2. The concave glass substrate 2 is connected to the negative electrode 12 of the anode bonding device, and the single-crystal silicon wafer is connected to the positive electrode 6 of the anode bonding device.

[0027] Example 1 A method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding, comprising the following specific steps: S1. Preparation of concave glass substrate: High borosilicate glass was selected to prepare a circular concave glass substrate with a diameter of 100 mm and a thickness of 12 mm. The target radius of curvature of the concave surface was 1 m. The concave surface was subjected to ultra-precision polishing to achieve a surface shape accuracy PV value ≤ 0.3 μm and a surface roughness Ra ≤ 0.2 nm. The concave surface was ultrasonically cleaned for 10 min in sequence with acetone, anhydrous ethanol, and deionized water. After being dried with nitrogen, it was placed in a vacuum oven at 120 ℃ for 2 h for later use.

[0028] S2 Silicon Wafer Pretreatment: Select single-sided polished N-type wafers. <110> A crystal-oriented single-crystal silicon wafer with a diameter of 50 mm and a thickness of 200 μm, and a surface roughness Ra≤0.2 nm on the polished surface; the wafer is ultrasonically cleaned for 10 min in sequence with acetone, anhydrous ethanol and deionized water, then wet etched with 3% HF solution for 30 s to remove the natural oxide layer on the surface, rinsed with deionized water and dried with nitrogen to complete the surface activation treatment, and is ready for use.

[0029] S3 Lamination and Pre-compression Bending: The polished surface of the pre-treated monocrystalline silicon wafer is aligned with the concave surface of the concave glass substrate to achieve precise coaxial alignment and bonding. Then, it is transferred to an open container, the container is evacuated, and air is injected into the space enclosed by the container lid and plastic film through the air inlet. The pressure in this space is adjusted to 0.5 MPa and held for 10 minutes. The pressure on the plastic film is transmitted to the monocrystalline silicon wafer, causing the monocrystalline silicon wafer to undergo controllable elastic deformation, completely fitting the curved contour of the concave glass with no visible gaps at the interface, thus obtaining the bonded assembly. S4 Anodic Bonding Fixing: Connect the concave glass substrate to the negative electrode of the anodic bonding equipment, and connect the monocrystalline silicon wafer to the positive electrode of the anodic bonding equipment. Evacuate to a vacuum level ≤ 5 × 10⁻⁶. -4 The temperature was programmed to 400 °C, and after stabilization, a bonding voltage of 1000 V was applied while maintaining a bonding pressure of 0.3 MPa for 10 min to complete anodic bonding. Subsequently, the pressure was slowly reduced and the temperature was programmed to decrease to room temperature, yielding a permanently bonded integrated curved crystal substrate. A schematic diagram illustrating the state changes between the concave glass substrate and the single-crystal silicon wafer in the above method is shown below. Figure 2 See the actual product image below. Figure 3 .

[0030] S5 Post-processing: The integrated curved crystal substrate is cut into 10 mm × 10 mm target size curved crystal wafers using laser cutting. The cut edges are ground and chamfered, and then the diffraction surface of the silicon single crystal is ultra-precisely polished to make the surface shape accuracy PV value ≤ 0.8 μm and the surface roughness Ra ≤ 0.3 nm, finally producing a silicon-based curved crystal monochromator.

[0031] The product prepared in Example 1 was subjected to structural characterization and performance testing, and the results are as follows: The silicon-based bent crystal monochromator prepared in Example 1 was tested using MiniPIX. Figure 4The performance test results page shows that the detector collected a total of 680,133 X-ray photons. The maximum signal per pixel was 1022, reflecting the peak intensity of the diffracted beam. The detector effectively operated with 64,887 pixels, approximately 256 × 256 = 65,536. The two-dimensional images also show that the presence of bright bands proves the bent crystal successfully met the Bragg diffraction conditions, producing the target monochromatic beam. The narrow width of the bright bands indicates good focusing performance of the bent crystal (small beam size, high energy concentration). The color uniformity of the bright bands reflects the lattice integrity and curvature processing accuracy of the bent crystal; uniform bright bands indicate high crystal quality and small processing errors. The intensity of the blue background reflects the system's stray scattering and detector noise level; a low background indicates reasonable optical path shielding and threshold settings. These data and images together reflect the concentrated signal and stable intensity of the bent crystal diffracted beam, and the detector's good operating condition, verifying the excellent performance of the bent crystal prepared in this invention.

[0032] Figure 5 This diagram verifies the consistency between the benchtop X-ray absorption spectrum (XAFS) produced using the bent crystal monochromator prepared according to this invention and the X-ray absorption test results of Zn from a synchrotron radiation source. The solid line represents the benchtop XAFS test results, and the dashed line represents the synchrotron radiation source test results. The comparison shows that the two X-ray absorption curves almost overlap. This verifies that the benchtop XAFS performance of the bent crystal prepared using the method of this invention can reach the level of a synchrotron radiation source.

[0033] Comparative Example 1 The comparative example describes a method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding, which is basically the same as in Example 1, except that in step S4, the temperature is raised to 300 °C to begin anodic bonding.

[0034] Performance test results: Due to insufficient temperature, ion migration in the glass is slow, electrostatic adsorption in the contact area is weak, the curved bonding area is difficult to expand, and many local unbonded areas appear, such as... Figure 6 As shown.

[0035] Comparative Example 2 The comparative example describes a method for fabricating a silicon-based bent monochromator based on concave glass bending and anodic bonding, which is basically the same as in Example 1, except that in step S4, the bonding DC voltage is adjusted to 700V.

[0036] Performance test results Due to insufficient voltage and electric field, ions migrate slowly in the glass. Since the initial contact of the curved surface is often only in the center or part of the area, insufficient voltage causes the anodic bonding front to be unable to overcome the elastic recovery force of the silicon wafer.

[0037] Comparative Example 3 The comparative example describes a method for fabricating a silicon-based bent monochromator based on concave glass bending and anodic bonding, which is basically the same as in Example 1, except that in step S4, the bonding pressure is increased to 5 MPa.

[0038] Performance test results Excessive pressure applied to the silicon wafer caused the edges of the wafer to crack, such as... Figure 7 As shown.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0040] It should be noted that in other embodiments, the objective of this invention can be achieved when the experimental process meets the following conditions: The preferred bonding temperature is 360-410 °C, specifically 360 °C, 380 °C, 400 °C, or 410 °C. For the bonding voltage, 800 V to 1000 V is preferred, specifically 800 V, 900 V or 1000 V, etc. The bonding pressure is preferably 0.2 MPa to 3 MPa, specifically 0.2 MPa, 1 MPa, 2 MPa or 3 MPa, etc. For bonding holding time, it is preferred to be 5 min to 10 min, specifically 5 min, 7 min, 9 min or 10 min, etc.

[0041] Those skilled in the art can make appropriate selections of the above process parameters according to actual needs, and all of them can achieve the purpose of this invention.

[0042] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding, characterized in that, Includes the following steps: Provide open containers; A concave glass substrate with a preset radius of curvature is placed inside an open container, and a monocrystalline silicon wafer is placed on the top surface of the concave glass substrate. A plastic film is placed on top of an open container, forming a sealed cavity with the open container; a container lid is placed above the plastic film, with an air inlet in the middle of the container lid; and an air extraction hole is provided on the side wall of the open container. Vacuuming is performed on the sealed cavity through the air extraction hole, and gas is injected into the space formed by the container lid and the plastic film through the air filling port, so that the pressure in the space reaches the preset bonding pressure. Under the action of the pressure difference on both sides of the plastic film, the plastic film bends downward and transmits the pressure to the surface of the monocrystalline silicon wafer, causing the monocrystalline silicon wafer to undergo elastic deformation and completely fit the concave curved surface contour of the concave glass substrate, thus obtaining the bonded assembly. A concave glass substrate and a single-crystal silicon wafer are connected to the negative and positive electrodes of an anodic bonding device, respectively. Anodic bonding is performed under preset bonding temperature, bonding voltage, and bonding pressure. After post-processing, a silicon-based bent crystal monochromator is obtained.

2. The method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding according to claim 1, characterized in that, The concave glass substrate has a radius of curvature of 0.5 m to 2 m, a surface shape accuracy PV value of ≤1 μm, and a surface roughness Ra of ≤0.5 nm.

3. The method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding according to claim 2, characterized in that, Before use, the concave glass substrate is ultrasonically cleaned in sequence with acetone, anhydrous ethanol, and deionized water. After cleaning, it is dried with nitrogen and then vacuum dried.

4. The method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding according to claim 2, characterized in that, The concave glass substrate is made of borosilicate glass.

5. The method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding according to claim 1, characterized in that, The monocrystalline silicon wafer is a single-sided polished N-type or P-type wafer. <100> , <111> or <110> Crystal-oriented single-crystal silicon wafers with a thickness of 100 μm to 1000 μm and a surface roughness Ra≤0.3 nm on the polished surface.

6. The method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding according to claim 5, characterized in that, The single-crystal silicon wafer is polished, cleaned, and surface activated before use; the surface activation treatment is oxygen plasma treatment, argon ion sputtering treatment, or hydrofluoric acid wet etching treatment.

7. The method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding according to any one of claims 1 to 6, characterized in that, The bonding pressure is 0.1 MPa to 3 MPa, and the bonding holding time is 5 min to 10 min.

8. The method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding according to claim 7, characterized in that, The bonding temperature is 360-410 ℃.

9. The method for fabricating a silicon-based bent crystal monochromator based on concave glass bending and anodic bonding according to claim 7, characterized in that, The bonding voltage is 800 V to 1000 V.

10. A silicon-based bent crystal monochromator, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 9; the silicon-based bent crystal monochromator includes a concave glass substrate and a single crystal silicon wafer permanently bonded to the concave surface of the concave glass substrate by anodic bonding.

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