Filter disc for X-ray and soft X-ray wave bands and preparation method thereof
阅读说明：本技术 一种用于x射线与软x射线波段的滤片及其制备方法 (Filter disc for X-ray and soft X-ray wave bands and preparation method thereof ) 是由 陈溢祺 朱忆雪 张秀霞 金宇 朱东风 朱运平 金长利 于 2020-12-31 设计创作，主要内容包括：本发明提供了一种用于X射线与软X射线能段的滤片及其制备方法,属于光学元件技术领域。本发明中含有Sc层的滤片透射率在K吸收边0.276nm(E＝4500eV)和L吸收边2.48nm(E＝500eV)前后有非常明显的对比。由于B的吸收边在190eV,本发明提供的滤片在0.276nm～0.31nm(4000～4500eV)和2.48nm～6.53nm(190～500eV)范围内可以有效地对高次谐波进行抑制。本发明提供的滤片的制备方法,本发明先刻蚀硅片再镀膜,得到的滤片的品质高,无砂眼现象。实施例的数据表明,本发明制得的Sc/B-4C滤片或自支撑Sc/B-4C滤片(含有聚酰亚胺膜),均观察不到砂眼。(The invention provides a filter disc for an X-ray energy section and a soft X-ray energy section and a preparation method thereof, belonging to the technical field of optical elements. The transmittance of the filter containing the Sc layer according to the invention is very clearly compared between the K absorption edge of 0.276nm (E4500 eV) and the L absorption edge of 2.48nm (E500 eV). As the absorption edge of B is 190eV, the filter provided by the invention can effectively inhibit higher harmonics within the ranges of 0.276-0.31 nm (4000-4500 eV) and 2.48-6.53 nm (190-500 eV). Book (I)According to the preparation method of the filter disc, the silicon wafer is etched firstly and then the film is coated, so that the obtained filter disc is high in quality and free of a sand hole phenomenon. The data of the examples show that the Sc/B produced according to the invention 4 C filter disc or self-supporting Sc/B 4 No voids were observed in any of the C filters (containing polyimide film).)
1. One kind is usedThe filter disc in X-ray and soft X-ray wave bands is characterized by comprising a Sc layer and a B layer which are alternately stacked in sequence4And C, layer.
2. The filter element according to claim 1, wherein the number of the alternately stacked cycles is 10 to 30.
3. The filter sheet of claim 2, wherein each layer of Sc has a thickness of 200-300 nm and each layer of B has a thickness of 200-300 nm4The thickness of the C layer is 20-40 nm.
4. The filter of claim 1, further comprising a self-supporting membrane.
5. The filter element of claim 4, wherein the free-standing membrane is a polyimide membrane.
6. The filter disc according to claim 4 or 5, wherein the thickness of the self-supporting membrane is 1.7 ± 0.5 μm.
7. The method for preparing a filter disc as claimed in any one of claims 1 to 6, comprising the steps of:
depositing a polyimide film on a polished surface of a silicon wafer by adopting a thermal evaporation method, etching the non-polished surface of the silicon wafer to expose the polyimide film, and sequentially carrying out a Sc layer and a B layer on the surface of the exposed polyimide film by adopting a magnetron sputtering method4And performing magnetron sputtering coating on the layer C to obtain the filter disc.
8. The method for preparing a filter disc as claimed in any one of claims 1 to 6, comprising the steps of:
depositing a polyimide film on the polished surface of a silicon wafer by adopting a thermal evaporation method, and then sequentially carrying out a Sc layer and a B layer on the surface of the polyimide film by adopting a magnetron sputtering method4And performing magnetron sputtering coating on the layer C to obtain the filter disc.
9. The production method according to claim 7 or 8, wherein the magnetron sputtering coating uses a Sc target and B4C target, the sputtering power of the Sc target is 60W, and B4The sputtering power of the C target was 120W.
10. The method according to claim 7 or 8, wherein the sputtering pressure of the magnetron sputtering coating film is 0.1 to 0.5 Pa.
Technical Field
The invention relates to the technical field of optical elements, in particular to a filter disc for X-ray and soft X-ray wave bands and a preparation method thereof.
Background
The wave bands of the X-ray and the soft X-ray cover resonance lines of most elements, the wavelength is short, the penetrability is strong, and nondestructive measurement can be realized, so that the wave bands are important research tools in the research fields of biology, medicine, materials, physics, chemistry and the like. With the rapid development of high-brightness synchrotron radiation light sources, scientists in various countries have increasingly strong interest in the characterization and research of the optical properties of materials in the wave band. The continuous spectrum generated by the synchrotron radiation is always inevitably mixed with the higher harmonic lambda of the fundamental lambda after passing through the monochromatornλ/n, which affects the test results, and therefore filters are commonly used to eliminate higher harmonics. The basic principle of the filter is that the wavelength band is selected by utilizing the change of the transmissivity of the material before and after the absorption edge, so that the filtering effect is achieved.
In the prior art, transmission gratings such as Muller of Germany are used for researching the higher harmonic component of a Toroidal Grating Monochromator (TGM) in a VUV short wave band, analyzing the higher harmonic distribution of the wave band with the wavelength range of 5-45 nm when the energy is 337MeV, and researching the higher harmonic distribution of the wave band with energy of 756MeV after a Be (100nm) and an Al (200nm) filter are added to the wave band, wherein the higher harmonic is less than 10% after the filter is added; in order to inhibit higher harmonics, the Livermore laboratory in the United states adopts a method of combining three-mirror reflection of grazing incidence and a Be film, and achieves elimination of the higher harmonics by utilizing reflection at a total reflection angle; an eight-prism double-mirror reflection higher harmonic suppression device is designed by Nigri corporation of Japan by utilizing BL28A of Photo Factory, the device comprises eight pairs of reflector sets, each pair of reflector sets comprises low-pass filters with different cut-off frequencies, the low-pass filters cover the energy range of 80-1600 MeV, and the low-pass filters are used for suppressing the higher harmonics of soft X rays emitted by a grazing incidence grating monochromator. The above-mentioned various methods are experimental methods which are adopted for different beam line station structures of each experimental station, and the structures of the beam line and the experimental station need to be changed, so that the problems of complicated operation and high cost exist.
Disclosure of Invention
In view of the above, the present invention is directed to a filter for X-ray and soft X-ray bands. The filter disc provided by the invention can effectively improve the transmission performance to high-energy harmonic waves.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a filter disc for X-ray and soft X-ray wave bands, which comprises a Sc layer and a B layer which are alternately stacked in sequence4And C, layer.
Preferably, the number of the alternately stacked cycles is 10 to 30.
Preferably, each Sc layer has a thickness of 200-300 nm, and each B layer4The thickness of the C layer is 20-40 nm.
Preferably, the filter sheet further comprises a self-supporting membrane.
Preferably, the self-supporting film is a polyimide film.
Preferably, the thickness of the self-supporting film is 1.7 ± 0.5 μm.
The invention also provides a preparation method of the filter disc in the technical scheme, which comprises the following steps:
depositing a polyimide film on a polished surface of a silicon wafer by adopting a thermal evaporation method, etching the non-polished surface of the silicon wafer to expose the polyimide film, and sequentially carrying out a Sc layer and a B layer on the surface of the exposed polyimide film by adopting a magnetron sputtering method4And C, coating a film on the layer to obtain the filter disc.
The invention also provides a preparation method of the filter disc in the technical scheme, which comprises the following steps:
depositing a polyimide film on the polished surface of a silicon wafer by adopting a thermal evaporation method, and then sequentially carrying out a Sc layer and a B layer on the surface of the polyimide film by adopting a magnetron sputtering method4Magnetism of C layerAnd controlling sputtering coating to obtain the filter disc.
Preferably, the magnetron sputtering coating uses a Sc target and B4C target, the sputtering power of the Sc target is 60W, and B4The sputtering power of the C target was 120W.
Preferably, the sputtering pressure of the magnetron sputtering coating is 0.1-0.5 Pa.
The invention provides a filter (Sc/B) for X-ray and soft X-ray wave bands4C) Comprises a Sc layer and a B layer which are alternately stacked in sequence4And C, layer. In the present invention, the transmittance of the filter containing the Sc layer is very clearly compared before and after the absorption edge, and B4Function of layer C: first, a protective layer, B4The layer C is a compact ceramic material and is extremely stable, and the Sc layer below the layer C is protected; secondly, stress is balanced; and thirdly, filtering soft X-rays in an energy band around 180 eV. In the present invention, the transmittance of the filter containing the Sc layer was clearly compared between the K absorption edge of 0.276nm (E4500 eV) and the L absorption edge of 2.48nm (E500 eV). As the absorption edge of B is 190eV, the filter provided by the invention can effectively inhibit higher harmonics within the ranges of 0.276-0.31 nm (4000-4500 eV) and 2.48-6.53 nm (190-500 eV).
Furthermore, the filter disc provided by the invention also comprises a polyimide film (PI film), and the polyimide film as a self-supporting film can improve the strength of the filter disc, so that the filter disc with high transmissivity, good mechanical property and strong vibration resistance can be obtained.
The invention also provides a preparation method of the filter disc, which comprises the following steps: depositing a polyimide film on a polished surface of a silicon wafer by adopting a thermal evaporation method, etching the non-polished surface of the silicon wafer to expose the polyimide film, and sequentially carrying out a Sc layer and a B layer on the surface of the exposed polyimide film by adopting a magnetron sputtering method4C layer coating to obtain the filter disc or depositing a polyimide film on the polished surface of the silicon wafer by adopting a thermal evaporation method, and then sequentially carrying out the Sc layer and the B layer on the surface of the polyimide film by adopting a magnetron sputtering method4And performing magnetron sputtering coating on the layer C to obtain the filter disc.
The invention etches the silicon chip first and then coats the film to obtain the quality of the filterHigh strength and no sand hole. The data of the examples show that the Sc/B produced according to the invention4C filter disc or self-supporting Sc/B4No voids were observed in any of the C filters (containing polyimide film).
Drawings
FIG. 1 is a schematic representation of Sc/B at different sputtering pressures for example 14C, a curvature and stress variation trend graph of the multilayer film;
FIG. 2 is a graph showing transmittance curves of the filter obtained in example 1;
FIG. 3 is the PI/(Sc/B) ratio for different sputter cycles of measurement and control in example 14C) A physical map of the filter, wherein (a) is a typical broken sample and (b) is a non-broken sample;
FIG. 4 is a diagram showing the detection of blisters on the filter of example 2, wherein 1 is PI/(Sc/B)4C) Filter disc, 2 is not plated with Sc/B4C. 3 is Sc/B4C；
Fig. 5 is a graph showing the test and theoretical calculation of the composite filter in example 3.
Detailed Description
The invention provides a filter disc for X-ray and soft X-ray wave bands, which comprises a Sc layer and a B layer which are alternately stacked in sequence4And C, layer.
In the present invention, the number of the alternately stacked cycles is preferably 10 to 30, and more preferably 20.
In the present invention, the thickness of each Sc layer is preferably 200 to 300nm, more preferably 240nm, and each B layer4The thickness of the C layer is preferably 20-40 nm, and more preferably 36 nm.
In the present invention, the filter sheet preferably further comprises a self-supporting membrane, and the self-supporting membrane is preferably a polyimide membrane.
In the present invention, the thickness of the self-supporting film is preferably 1.7. + -. 0.5. mu.m.
The invention also provides a preparation method of the filter disc in the technical scheme, which comprises the following steps:
depositing a polyimide film on a polished surface of a silicon wafer by adopting a thermal evaporation method, etching the non-polished surface of the silicon wafer to expose the polyimide film, and sequentially forming the polyimide film on the surface of the exposed polyimide film by adopting a magnetron sputtering methodCarrying out Sc layer and B4And C, coating a film on the layer to obtain the filter disc.
In the present invention, the magnetron sputtering coating film is preferably formed using a Sc target and B4C target, the sputtering power of the Sc target is preferably 60W, and B4The sputtering power of the C target is preferably 120W.
In the present invention, the sputtering pressure of the magnetron sputtering coating is preferably 0.1 to 0.5Pa, and more preferably 0.3 to 0.4 Pa.
In the present invention, the degree of vacuum of the evaporation plating film is preferably less than 2X 10-4Pa。
The invention also provides another preparation method of the filter disc in the technical scheme, which comprises the following steps:
depositing a polyimide film on the polished surface of a silicon wafer by adopting a thermal evaporation method, and then sequentially carrying out a Sc layer and a B layer on the surface of the polyimide film by adopting a magnetron sputtering method4And performing magnetron sputtering coating on the layer C to obtain the filter disc.
The specific operation of the magnetron sputtering coating is preferably consistent with the scheme, and the detailed description is omitted.
In order to further illustrate the present invention, the following filter for X-ray and soft X-ray bands and the method for preparing the same according to the present invention will be described in detail with reference to examples, which should not be construed as limiting the scope of the present invention.
In the embodiment of the invention, the optical performance of the filter is characterized in Beijing synchrotron radiation device and national synchrotron radiation laboratories (BSRF and NSRL).
Example 1
A filter disc for X-ray and soft X-ray wave bands comprises a Sc layer and a B layer which are sequentially and alternately stacked4C layers, the number of the alternately laminated cycles is 20, the thickness of each Sc layer is 240nm, and each B layer4The thickness of the C layer is 36nm, and the filter disc also comprises a polyimide film which is a self-supporting film and has the thickness of 1.7 mu m.
The preparation method comprises the following steps:
firstly, a layer of PI film with the thickness of 1.7 mu m is deposited on the polished surface of a silicon wafer by adopting a thermal evaporation method, and the non-polished surface of the silicon wafer is firstlyEtching a circular groove area with the size of the required filter disc, wherein the diameter of the circular groove is 10mm, completely etching silicon in the circular groove in the process, exposing the PI film, and then performing magnetron sputtering on the Sc/B4C(Sc：4.8μm，B4C: 0.72 μm) was deposited on the PI film, Sc/B4The C film is totally divided into 20 periods, and in each period, the Sc plating is carried out for 240nm, and the B film is coated with the silicon dioxide4C plating at 36nm, wherein FIG. 1 shows Sc/B at different sputtering pressures4C curvature and stress variation trend chart of multilayer film, Sc target and B in magnetron sputtering process4The sputtering power of the C target is 60W and 100W respectively, the interval thickness is 48nm and 7.2nm respectively, the solid point in the figure represents Sc, the hollow point represents B4C. From the stress change chart, it can be seen that Sc shows a tensile stress trend, and B4C shows a pressure stress trend. Sc/B in the process of increasing the sputtering pressure from 0.1Pa to 0.5Pa4The curvature of C shows an increasing trend, the corresponding stress also changes from compressive to tensile, the average stress reaching a minimum between 0.3Pa and 0.4Pa, as shown in table 1.
TABLE 1 Sc/B at different sputtering pressures4Average stress test result of C filter
Sputtering gas pressure
0.1Pa
0.2Pa
0.3Pa
0.4Pa
0.5Pa
Stress value/Mpa
-263.9
-101.5
-30.8
26.4
31.6
FIG. 2 is a graph showing the transmittance of the filter obtained in example 1.
During the magnetron sputtering deposition, it is found that when the period is carried out to 10, the PI film sample in the vacuum chamber can be cracked from the edge or from the middle, because the time for coating the film is too long, the heat generated by the magnetron sputtering process is accumulated on the PI film to crack the PI film, and the Sc/B4C is too thick, the PI film is cracked due to the increase of stress, and PI/(Sc/B) is obtained after 20 complete plating cycles in the vacuum cavity4C) The composite filter element has only a small portion that is not fractured and has no voids, as shown in fig. 3.
Example 2
A filter for X-ray and soft X-ray bands is the same as in example 1.
The preparation method comprises the following steps:
etching a circular groove-shaped area with the diameter of 5mm on the non-polished surface of the silicon wafer, exposing the PI film, and sputtering and depositing Sc/B on the PI film4C, the whole process is carried out in 20 cycles, and the Sc target and the B are subjected to magnetron sputtering4The sputtering power of the C target is 60W and 100W respectively, the interval thickness is 48nm and 7.2nm respectively, and the method is used for depositing Sc/B on the PI film4At C, the cracking of PI film is obviously reduced, and the PI film and Sc/B4The yield of the C composite filter disc is greatly improved. The preparation method has the advantages that the circular groove-shaped area for etching the silicon wafer is small, and Sc/B is deposited on the PI film4And C, the PI film is not subjected to enough stress to crack the PI film, and more heat generated in the sputtering process can be transferred to the silicon wafer. No voids were observed in the small PI film etched areas as shown in fig. 4. In FIG. 4, 1 is PI/(Sc/B)4C) Filter disc, 2 is not plated with Sc/B4C. 3 is Sc/B4And C, sand hole detection.
Example 3
Laser indirect drive inertial confinement fusion research
A novel M-band flat response detector is composed of Sc/B4The C filter (prepared in example 1), the thick Sc filter (41 μ M) with duty cycle, and the Al cathode XRD are combined, and the flat response detection of the M band is realized by using the multilayer element filter with duty cycle in combination with the cathode response curve.
Wherein the thick Sc filter disc with the thickness of 41 mu m is used for obtaining a pinhole array by adopting a laser burning or machining mode, and the duty ratio of the pinhole array is 18 percent.
The composite filter is used for carrying out transmittance test on an X-ray source of a Beijing synchrotron radiation laboratory (BSRF), and a laboratory station consists of two X-ray beams of a soft energy area beam line (the energy interval is 100-1650 eV) and a middle energy area beam line (the energy interval is 2100-5600 eV). Due to the lack of a light source of 1650-2100 eV, the data in the interval is the general property of the reference transmissivity and is obtained by interpolation by utilizing the existing measurement results. Due to the pinhole duty ratio of the thick Sc filter disc, the theoretical calculation curve is formed by T (Sc/B)4C) X 18% and T (Sc + Sc/B)4C) X 82% (T represents transmittance) of the total composition. FIG. 5 shows the measured and theoretically calculated transmission curves of the composite filter, which are very close to each other, with the maximum transmission values near the Sc-K edge of 36.5% and 34.5%, respectively, and the measured results are slightly larger than the theoretically calculated results because of the Sc/B4The C filter disc has tiny sand holes, the X-ray beam reaches the soft X-ray wave band, the energy is high, the penetrating power is strong, the X-ray directly passes through the composite filter disc to cause the test result to be larger, and the result shows that the preparation of the composite filter disc basically meets the experimental requirements.
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be construed as the protection scope of the present invention.
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