Gas isolation device for near-ambient pressure X-ray photoelectron spectrometer, preparation method and application thereof

Abstract

The present invention relates to the field of gas isolation in synchrotron radiation near-ambient pressure X-ray photoelectron spectroscopy, specifically to a gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer, its preparation method and application. The isolation device provided by the present invention combines a double-sided silicon nitride window with a through-hole conical hole and a hollow frustum metal component. The through-hole conical hole is an ultra-small size silicon nitride window, which can achieve an ultra-high pressure difference between the detector region and the sample region, and obtain an ability to isolate gases far exceeding that of the prior art, solving the drawbacks of the prior art in terms of too large aperture and difficulty in achieving high working pressure. Experiments show that for a near-ambient pressure X-ray photoelectron spectrometer using the isolation device of the present invention, when the pressure on the high-pressure side is 1010 mbar, the pressure on the low-pressure side is about 9.36×10-3 mbar.

Description

Technical Field

[0001] The present invention relates to the field of gas isolation in synchrotron radiation near-ambient pressure X-ray photoelectron spectroscopy, specifically to a gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer, its preparation method and application. Background Art

[0002] In X-ray photoelectron spectroscopy at near-ambient pressure (NAP-XPS), it is crucial to maintain a stable pressure difference between the sample and the detector. Traditional methods usually rely on complex differential pumping systems or mechanical seals to isolate the sample from the detector, especially when analyzing materials under near-ambient conditions. However, these systems can be bulky, prone to mechanical failures, and less efficient in controlling the pressure gradient. Therefore, a simpler and more reliable method is needed to effectively isolate gases while maintaining the required vacuum for the detector.

[0003] In some existing designs, metal processing techniques are used to manufacture a tapered hole component to isolate the sample from the detector. The tapered hole component is usually a conical component with a gradually decreasing pore size from the lower bottom surface to the upper top surface, and is commonly used in multi-stage differential pumping systems. It generates an effective pressure gradient by gradually reducing the pore size, thereby isolating the sample area from the detector area without direct contact. The existing tapered hole components are limited by the metal processing technology and the characteristics of metal materials. The size of the narrowest part of its pore diameter is between 300 µm and 1000 µm. The too large pore diameter may make the gas flow control inaccurate and it is difficult to obtain a large pressure difference. The photoelectron detector and the X-ray source need to operate in an ultra-high vacuum environment. The small pressure difference makes it difficult to conduct experiments under near-ambient pressure conditions. The mainstream of the existing synchrotron radiation near-ambient pressure X-ray photoelectron spectroscopy experimental stations uses a tapered hole component with the narrowest pore diameter of 300 µm to reach a pressure of 30 mbar, and the vacuum degree of the photoelectron detector deteriorates significantly under high working pressure. The existing working pressure (30 mbar) is difficult to meet the requirements of various tests. Therefore, there is an urgent need for an ultra-small tapered hole component to reduce the intake gas flow rate and maintain the required vacuum degree of the photoelectron detector.

[0004] Silicon nitride (Si3N4) is a ceramic material with high strength, chemical stability and high temperature resistance, and is widely used in many fields. Traditional silicon nitride windows are usually manufactured by chemical vapor deposition (CVD) or thin film deposition techniques. Due to the high hardness of silicon nitride, its processing is relatively complex and the price is high, especially for tapered hole components that require high-precision pore diameter design. Summary of the Invention

[0005] In view of this, the technical problem to be solved by the present invention is to provide a gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer, its preparation method and application. The isolation device provided by the present invention can not only provide an ultra-high pressure difference between the sample area and the detector area in the instrument, but also ensure the normal operation of the near-ambient pressure X-ray photoelectron spectrometer.

[0006] The present invention provides a gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer, comprising:

[0007] A hollow frustum-shaped metal component, the lower bottom surface of the hollow frustum-shaped metal component is open and the upper bottom surface is provided with a through hole;

[0008] A double-sided silicon nitride window with a through conical hole connected to the upper bottom surface of the hollow frustum-shaped metal component, the aperture size of the small end of the through conical hole is 20 µm to 800 µm, and the large end of the through conical hole is connected to the through hole on the upper bottom surface of the hollow frustum-shaped metal component.

[0009] The gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer provided by the present invention is a combined device of a double-sided silicon nitride window with an ultra-small size silicon nitride window and a hollow frustum-shaped metal component, which can solve the disadvantages of the prior art in terms of too large aperture and difficulty in achieving high working pressure.

[0010] The isolation device provided by the present invention includes a hollow frustum-shaped metal component. The hollow frustum-shaped metal component is a ring of the multi-stage magnetic lens of the photoelectron analyzer. If the hollow frustum-shaped metal component of the present invention is missing, it will have a negative impact on the photoelectrons, thereby affecting the normal operation of the near-ambient pressure X-ray photoelectron spectrometer.

[0011] The hollow frustum-shaped metal component described in the present invention is a hollow frustum-shaped metal component made of metal with only a side surface and an upper bottom surface, and its lower bottom surface is open. In addition, its upper bottom surface is provided with a through hole. The material of the hollow frustum-shaped metal component described in the present invention is Inconel 625 alloy. Although the cost of manufacturing the hollow frustum-shaped metal component described in the present invention using Inconel 625 alloy is higher than that of 304 stainless steel substrate, due to no special dimensions and curved surfaces, the overall price is moderate.

[0012] The diameter of the upper bottom surface of the hollow frustum-shaped metal component described in the present invention is 4 mm to 5 mm; the diameter of the lower bottom surface has no special limitation as long as it can be matched and connected with the multi-stage differential pumping device in the near-ambient pressure X-ray photoelectron spectrometer. The aperture size of the through hole on the upper bottom surface of the hollow frustum-shaped metal component described in the present invention is 0.5 mm to 2.75 mm, preferably 0.8 mm to 2 mm, more preferably 0.8 to 1.5 mm; if the through hole is a square through hole, the aperture size means that the length and width are independently 0.5 mm to 2.75 mm, preferably 0.8 mm to 2 mm, more preferably 0.8 to 1.5 mm; if the through hole is circular, the aperture size means that the diameter is 0.5 mm to 2.75 mm, preferably 0.8 mm to 2 mm, more preferably 0.8 to 1.5 mm; if the through hole is irregularly shaped, the size means that the equivalent circle diameter of the area of the through hole is 0.5 mm to 2.75 mm, preferably 0.8 mm to 2 mm, more preferably 0.8 to 1.5 mm. In some embodiments of the present invention, the through hole is a through round hole with a diameter of 0.5 mm to 2.75 mm. In some embodiments of the present invention, the through hole is a through round hole with a diameter of 0.8 mm to 2 mm. In some embodiments of the present invention, the through hole is a through round hole with a diameter of 0.8 mm to 1.5 mm.

[0013] The side surface of the hollow frustum-shaped metal component described in the present invention is also provided with threaded holes, so that the isolation device described in the present invention can be threadedly connected with the near-ambient pressure X-ray photoelectron spectrometer during application. Specifically, the edge of the lower bottom surface of the hollow frustum-shaped metal component described in the present invention is also provided with an inner edge extending horizontally inward, and the extension dimension of the inner edge only needs to be able to accommodate the threaded holes of conventional sizes in the art. At least four threaded holes symmetrically arranged in pairs are provided on the inner edge, and preferably at least six threaded holes symmetrically arranged in pairs are provided; the threaded holes penetrate the side surface and the inner edge of the hollow frustum-shaped metal component in the vertical direction. A circle of O-shaped channels is also provided on the lower wall of the inner edge described in the present invention for further enhancing airtightness.

[0014] The isolation device provided by the present invention further includes a double-sided silicon nitride window plate with a through-hole taper provided on the upper bottom surface of the hollow frustum-shaped metal component. It is made of the double-sided silicon nitride window plate, and the double-sided silicon nitride window plate includes: a silicon wafer substrate and a first silicon nitride thin film and a second silicon nitride thin film respectively provided on both sides of the silicon wafer substrate. Among them, the thicknesses of the first silicon nitride thin film and the second silicon nitride thin film are independently 80 nm to 120 nm; the thickness of the silicon wafer substrate is 200 µm to 500 µm. Preferably, the silicon wafer substrate is a P-type silicon wafer substrate. Preferably, the silicon wafer substrate is a silicon wafer substrate with a 100 crystal orientation. In some embodiments of the present invention, the angle between the wall of the through-hole taper and the horizontal direction is: 54.7 degrees.

[0015] The through-hole taper on the double-sided silicon nitride window plate with a through-hole taper provided in the present invention is the silicon nitride window. It is a through-hole with a gradually changing aperture size that penetrates the entire double-sided silicon nitride window plate. One end with the widest aperture of the through-hole taper is the large end, and one end with the narrowest aperture is the small end. The aperture size of the through-hole taper gradually decreases from the large end to the small end. The aperture size of the small end of the through-hole taper in the present invention is 20 µm to 800 µm, preferably 20 µm to 80 µm. The aperture size of the large end of the through-hole taper in the present invention is 0.3 mm to 1.1 mm, preferably 0.3 mm to 0.4 mm. The aperture size of the large end of the through-hole taper is smaller than the aperture size of the through-hole on the upper bottom surface of the hollow frustum-shaped metal component, leaving a margin for subsequent pasting operations to prevent blocking the holes on the window plate. The through-hole taper in the present invention is preferably a quadrangular frustum taper hole. Both its large end and small end are square. The aperture size of its small end means the length and width dimensions of its small end. The length and width of its small end are independently 20 µm to 800 µm, preferably 20 µm to 80 µm; the aperture size of its large end means the length and width dimensions of its large end. The length and width of its large end are independently 0.3 mm to 1.1 mm, preferably 0.3 mm to 0.4 mm. In some embodiments of the present invention, the through-hole taper in the present invention is a regular quadrangular frustum taper hole. Both its large end and small end are square. The side length of its small end is 20 µm to 800 µm, preferably 20 µm to 80 µm; the side length of its large end is 0.3 mm to 1.1 mm, preferably 0.3 mm to 0.4 mm.

[0016] The large end of the through-hole conical hole on the double-sided silicon nitride-coated window pane with a through-hole conical hole according to the present invention is connected to the through-hole on the upper bottom surface of the hollow frustum-shaped metal component. That is, the double-sided silicon nitride-coated window pane with a through-hole conical hole according to the present invention is connected to the upper bottom surface of the hollow frustum-shaped metal component with the side where the large end of its through-hole conical hole is located, and the side where the small end of its through-hole conical hole is located faces outward. The size of the double-sided silicon nitride-coated window pane with a through-hole conical hole according to the present invention is less than 2.75 mm, preferably 2.4 mm to 2.6 mm. If the double-sided silicon nitride-coated window pane with a through-hole conical hole is square, the size means that the length and width are independently less than 2.75 mm, preferably 2.4 mm to 2.6 mm; if the double-sided silicon nitride-coated window pane with a through-hole conical hole is circular, the size means that the diameter is less than 2.75 mm, preferably 2.4 mm to 2.6 mm; if the double-sided silicon nitride-coated window pane with a through-hole conical hole is irregular in shape, the size means that the equivalent circle diameter of the area of the window pane is less than 2.75 mm, preferably 2.4 mm to 2.6 mm.

[0017] The gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer provided by the present invention realizes the function of an ultra-small size silicon nitride window through the small end of the through-hole conical hole of the double-sided silicon nitride-coated window pane with a through-hole conical hole, and the ultra-small size silicon nitride window realizes physical isolation between the sample area and the detector area; through the hollow frustum-shaped metal component connected to the double-sided silicon nitride-coated window pane with a through-hole conical hole, based on the shape of its frustum and its through-hole, the air flow and pressure difference are further adjusted. The combination of the two effectively ensures gas isolation. The isolation device of the present invention not only simplifies the traditional multi-stage pumping system, but also effectively improves the stability and accuracy of the experiment.

[0018] The present invention also provides a preparation method for the gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer described in any one of the above, including the following steps: Glue the double-sided silicon nitride-coated window pane with a through-hole conical hole to the upper bottom surface of the hollow frustum-shaped metal component, so that the large end of the through-hole conical hole is connected to the through-hole on the upper bottom surface, and release the internal stress to obtain the gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer. Specifically, the present invention uses epoxy resin AB glue to glue the double-sided silicon nitride-coated window pane with a through-hole conical hole with the side where the large end of its through-hole conical hole is located to the upper bottom surface of the hollow frustum-shaped metal component. The gluing time is within 15 minutes, and then it is placed in a dry, dust-free and light-shielded environment to release the internal stress to obtain the gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer.

[0019] In some embodiments of the present invention, the double-sided silicon nitride-coated window pane with a through-hole conical hole is prepared by the following method:

[0020] S1) Form a layer of photoresist on the surface of the first silicon nitride thin film of the double-sided silicon nitride-coated window pane. Photolithograph a photolithographic opening area on the photoresist that is the same as the large end of the through-hole cone until the photolithographic opening area exposes the first silicon nitride thin film;

[0021] S2) Perform reactive ion etching (RIE) on the first silicon nitride thin film exposed in the photolithographic opening area until the photolithographic opening area exposes the silicon wafer substrate of the double-sided silicon nitride-coated window pane;

[0022] S3) Perform deep silicon etching and wet etching on the silicon wafer substrate exposed in the photolithographic opening area in sequence until the photolithographic opening area exposes the second silicon nitride thin film of the double-sided silicon nitride-coated window pane;

[0023] S4) Pierce the second silicon nitride thin film exposed in the photolithographic opening area to obtain the double-sided silicon nitride-coated window pane provided with the through-hole cone.

[0024] Specifically, in step S1) of the present invention, first, chemical polishing is performed on the first silicon nitride thin film of the double-sided silicon nitride-coated window pane to form a chemically polished surface on the surface of the first silicon nitride thin film for cleaning stains and removing dust; then, a spin-coating process is performed on the surface of the first silicon nitride thin film of the double-sided silicon nitride-coated window pane to form a layer of photoresist, and then a photolithography process is performed on the photoresist using a photomask to photolithograph a photolithographic opening area on the photoresist that is the same as the large end of the through-hole cone until the photolithographic opening area exposes the first silicon nitride thin film; the photolithography includes processes of exposure, development, cleaning, dust removal, and drying, and is used to form a transfer pattern of the silicon nitride window pattern on the photoresist. This transfer pattern is the photolithographic opening area. After exposure and development, the first silicon nitride thin film is exposed, while the unexposed and undeveloped non-photolithographic area is still covered with photoresist.

[0025] After step S1) of the present invention is performed, in step S2), reactive ion etching is performed on the first silicon nitride thin film exposed in the photolithographic opening area to etch and remove the first silicon nitride thin film provided on the silicon wafer substrate in the photolithographic opening area until the photolithographic opening area exposes the silicon wafer substrate.

[0026] After performing step S2) of the present invention, in step S3), deep silicon etching is first performed on the silicon wafer substrate exposed in the lithography opening area. Specifically, chloroform gas is used to etch the lithography opening area of the silicon wafer substrate until only a silicon residual layer remains in the lithography opening area; the etching magnetic field strength of the deep silicon etching is 0.8 Tesla to 1.2 Tesla, the etching radio frequency power of the deep silicon etching is 2800 watts to 3200 watts, the etching voltage of the deep silicon etching is 480 V to 520 V, and the etching time of the deep silicon etching is 10 minutes to 20 minutes.

[0027] After the deep silicon etching of the present invention, wet etching is then performed on the silicon residual layer until the second silicon nitride film is exposed in the lithography opening area; the wet etching is carried out using a high-concentration potassium hydroxide solution; the etching time of the wet etching is 110 minutes to 130 minutes, which can not only remove the silicon residual layer but also remove the photoresist layer in the non-lithography area. The present invention utilizes the crystal plane self-limiting property to form the aforementioned through-hole cone. For example, a silicon wafer substrate with a 100 crystal orientation will be etched along the 111 crystal orientation, and finally, the inner wall of the through-hole cone forms an angle of 54.7° with the horizontal direction.

[0028] After performing step S3) of the present invention, in step S4), the second silicon nitride film exposed in the lithography opening area is punctured to obtain the double-sided silicon nitride window with through-hole cones. In some embodiments of the present invention, a steel needle is used to puncture the second silicon nitride film exposed in the lithography opening area. Since the propagation depth of photoelectrons in silicon nitride is only 10 nanometers to 20 nanometers, after removing the second silicon nitride film, the obtained silicon nitride window with through-hole cones can be used to achieve physical isolation between the sample area and the detector area, and at the same time, it can transmit the photoelectron signal emitted by the sample.

[0029] The present invention also provides a near-ambient pressure X-ray photoelectron spectrometer, in which the detector area and the sample area are isolated by the gas isolation device for near-ambient pressure X-ray photoelectron spectrometer described in any of the above technical solutions. In some embodiments of the present invention, the near-ambient pressure X-ray photoelectron spectrometer includes: a detector area side cavity, a differential pumping device connected to the detector area cavity, a sample area cavity connected to the differential pumping device, and the gas isolation device for near-ambient pressure X-ray photoelectron spectrometer described in any of the above technical solutions provided between the detector area and the differential pumping device; the large end of the through-hole cone of the double-sided silicon nitride window with through-hole cones in the gas isolation device for near-ambient pressure X-ray photoelectron spectrometer faces the differential pumping device and the small end of the through-hole cone faces the detector area cavity; the differential pumping device makes the gas pressure change from high to low in the direction from the detector area cavity to the sample area cavity.

[0030] The present invention provides a gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer, a preparation method thereof, and an application. The isolation device provided by the present invention combines a double-sided silicon nitride window with a through-hole conical aperture and a hollow frustum metal component. The through-hole conical aperture is an ultra-small size silicon nitride window, which can achieve an ultra-high pressure difference between the detector region and the sample region, and obtain an isolation gas ability far exceeding that of the prior art, solving the drawbacks of the prior art in terms of too large aperture and difficulty in achieving high working pressure. Experiments show that for a near-ambient pressure X-ray photoelectron spectrometer using the isolation device of the present invention, when the pressure on the high-pressure side is 1010 mbar, the pressure on the low-pressure side is 9.36×10 -3 mbar, indicating that the isolation device of the present invention has an ultra-high vacuum working environment on the side of the photoelectron detector, and at the same time, the sample region can also obtain the ability to achieve a working pressure more than 3 times higher than the current working pressure (30 mbar). The isolation device provided by the present invention has a simple structure, low cost, convenient assembly, and convenient replacement. Different sizes of silicon nitride window plates can be replaced according to different experimental pressure requirements. Compared with the traditional experimental method of replacing the entire conical aperture, the experimental cost is greatly reduced, and the experimental efficiency is improved. The higher pressure obtained can be used to detect the surface chemical information of samples under near-ambient pressure, especially for the dynamic detection of reactions or processes carried out in a gas or liquid environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a side view of the raw material of the silicon nitride window plate used in the present invention;

[0032] Figure 2 is a schematic diagram of the preparation process of the double-sided silicon nitride window plate with a through-hole conical aperture described in the present invention;

[0033] Figure 3 is a schematic diagram of the large-end side of the double-sided silicon nitride window plate with a through-hole conical aperture described in the present invention;

[0034] Figure 4 is a schematic diagram of the small-end side of the double-sided silicon nitride window plate with a through-hole conical aperture described in the present invention;

[0035] Figure 5 is a side view of the double-sided silicon nitride window plate with a through-hole conical aperture described in the present invention;

[0036] Figure 6 is a front view of the hollow frustum metal component described in the present invention;

[0037] Figure 7 is a top view of the hollow frustum metal component described in the present invention;

[0038] Figure 8 is a bottom view of the hollow frustum metal component described in the present invention;

[0039] Figure 9 This is a top view of the gas isolation device for the near-ambient pressure X-ray photoelectron spectrometer according to the present invention;

[0040] Figure 10 This is a front view of the gas isolation device for the near-ambient pressure X-ray photoelectron spectrometer according to the present invention;

[0041] Figure 11 This is a schematic diagram of a conical hole test system equipped with the isolation device according to the present invention. Detailed implementation manners

[0042] The present invention discloses a gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer, its preparation method and application. Those skilled in the art can draw on the content of this article and appropriately modify the process parameters to achieve it. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art, and they are all regarded as included in the present invention. The method and application of the present invention have been described through preferred embodiments, and those related can obviously make changes or appropriate alterations and combinations to the methods and applications in this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0043] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "top surface", "bottom surface", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the indicated position or element must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation of the present invention. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In the description of the present invention, unless otherwise specified, the term "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a direct connection, or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0044] The present invention uses a silicon nitride window as a raw material to prepare a window with a silicon nitride window of ultra-small size, and then prepares an isolation device. The silicon nitride window used is a sandwich structure, the middle layer is a silicon wafer substrate with a <100> crystal orientation and a thickness of 200 µm, and the upper and lower layers are both silicon nitride thin films with a thickness of 100 nm. The silicon nitride thin films are evaporated on the surface of the silicon wafer substrate and are purchased from Addison Engineering. As Figure 1 shown, Figure 1 This is a side view of the raw material of the silicon nitride window used in the present invention, where 102 is the first silicon nitride thin film, 103 is the second silicon nitride thin film, and 104 is the silicon wafer substrate.

[0045] The present invention prepares a double-sided silicon nitride-coated window pane with a through-hole conical hole according to the process as Figure 2 shown. Figure 2 FIG. is a schematic diagram of the preparation process of the double-sided silicon nitride-coated window pane with a through-hole conical hole described in the present invention. It can be Figure 2 seen that the present invention uses the above-mentioned silicon wafer as the raw material, first performs cleaning and dust removal, and then coats photoresist on the surface of the first silicon nitride film with a spin coater; then covers the photoresist with a mask plate and performs exposure, development, cleaning, dust removal, drying, etc., so as to form a square area on the photoresist to expose the first silicon nitride film; then etches the exposed first silicon nitride film with RIE and removes the photoresist, so as to form a square window on the first silicon nitride film to expose the silicon wafer substrate; wet-etch the exposed silicon wafer substrate with a high-concentration potassium hydroxide solution, and utilize the crystal plane self-limiting property to form a regular window, and the window gradually becomes smaller and deeper along the <111> crystal plane direction into a conical hole, and finally leaves a 100-nm-thick second silicon nitride film; then use a special micron probe to pierce the second silicon nitride film to obtain the gas isolation window pane described in the present invention.

[0046] The present invention mainly relies on the devices and equipment of the University of Science and Technology Micro-Nano Processing Center, and mainly requires semiconductor processing equipment such as a mercury lamp lithography machine, a reactive ion etching machine, and a spin coater. The present invention uses an optical microscope to characterize the processing size and the bursting pressure to characterize the processing quality.

[0047] The following further elaborates the present invention in conjunction with embodiments:

[0048] " Example 1

[0049] (1) Preparation of a double-sided silicon nitride-coated window pane with a through-hole conical hole (window pane with an ultra-small-size silicon nitride window):

[0050] Step 1: Use the above-mentioned circular silicon nitride window pane with a diameter of 100 mm as the raw material, and perform chemical polishing on the first silicon nitride film to form a chemically polished surface on the surface of the first silicon nitride film for cleaning stains and removing dust;

[0051] Step 2: Perform a spin coating process on the surface of the first silicon nitride film to form a layer of photoresist;

[0052] Step 3: To simultaneously fabricate multiple silicon nitride window wafers with different window sizes, a photomask with square window patterns of various sizes is used to perform photolithography and development processes on the 100-mm-diameter silicon nitride window wafer wafer that has been processed in Steps 1 and 2. Subsequently, the finished wafer only needs to be divided into small pieces to obtain multiple silicon nitride window wafers, and each window wafer contains a silicon nitride window of one size. The photolithography and development processes are carried out on the first silicon nitride thin film coated with a layer of photoresist in Step 2, and the silicon nitride window pattern is transferred to the corresponding photoresist. The photolithography includes exposure, development, as well as cleaning, dust removal, and drying processes, which are used to form a transfer pattern of the silicon nitride window pattern on the photoresist, forming an exposed and developed photolithography opening area and an unexposed and undeveloped non-photolithography area of the photoresist, and exposing the pre-etching part of the first silicon nitride thin film that will be etched away in subsequent processes through the photolithography opening area;

[0053] Step 4: Perform reactive ion etching (RIE) on the first silicon nitride thin film in the photolithography opening area to etch and remove the silicon nitride located between the photolithography opening area and the silicon wafer substrate;

[0054] Step 5: Carry out a deep silicon etching process. Use chloroform gas to etch a silicon nitride window pattern trench on the area of the silicon wafer substrate exposed after the RIE in Step 4. And, a silicon residue layer remains between the bottom of the silicon nitride window pattern trench and the second silicon nitride thin film. The etching magnetic field strength of the deep silicon etching process is 1 Tesla, the etching radio frequency power of the deep silicon etching process is 3000 watts, the etching voltage of the deep silicon etching process is 500V, and the etching time of the deep silicon etching process is 15 minutes;

[0055] Step 6: Perform wet etching on the silicon wafer substrate with the silicon residue layer formed, etch and remove the silicon residue layer to complete the fabrication of the silicon nitride thin film window, and at the same time, it is used to completely remove the photoresist layer in the non-photolithography area; the wet etching is carried out using a high-concentration potassium hydroxide solution; the etching time of the wet etching is 120 minutes; a regular window is formed using the crystal plane self-limiting property, and the window gradually becomes smaller and deeper along the <111> crystal plane direction into a conical hole, and the angle between the conical hole wall and the horizontal direction is: 54.7 degrees; only the second silicon nitride thin film remains in the photolithography opening area;

[0056] Step 7: Use a self-made small and hard steel needle to pierce and remove the second silicon nitride thin film retained in Step 6 completely, obtaining a silicon nitride window wafer wafer with multiple different silicon nitride window sizes (i.e., the size of the small end of the through conical hole). Cut out the silicon nitride window wafer with a silicon nitride window size of 50 µm × 50 µm from it. The corresponding window large end size is 332.8 µm × 332.8 µm, and the whole size of the cut-out silicon nitride window wafer is 2.5 mm × 2.5 mm. AsFigures 3 - 5 As shown Figure 3 This is a schematic view of the large-end side of the double-sided silicon nitride-coated window pane with a through-tapered hole according to the present invention; Figure 4 This is a schematic view of the small-end side of the double-sided silicon nitride-coated window pane with a through-tapered hole according to the present invention; Figure 5 This is a side view of the double-sided silicon nitride-coated window pane with a through-tapered hole according to the present invention; wherein, 1 is the silicon nitride window pane, 101 is the ultra-small-size silicon nitride window, 102 is the first silicon nitride film, 103 is the second silicon nitride film, 104 is the silicon wafer substrate, 105 is the aforementioned photolithography opening area, and 106 is the aforementioned included angle.

[0057] (2) Preparation of the hollow frustum-shaped metal component:

[0058] Based on Inconel 625 alloy, a hollow frustum-shaped metal component is manufactured by using traditional metal processing techniques. The prepared hollow frustum-shaped metal component is matched with the silicon nitride window with a silicon nitride window size of 50 microns and a frame size of 2.5 mm obtained above. Its upper bottom surface platform is circular, with a diameter of 4.3 mm, and the through-hole on the upper bottom surface platform is circular, with a diameter of 1.2 mm. As Figures 6 - 8 shown Figure 6 This is a front view of the hollow frustum-shaped metal component according to the present invention, Figure 7 This is a top view of the hollow frustum-shaped metal component according to the present invention, Figure 8 This is a bottom view of the hollow frustum-shaped metal component according to the present invention; wherein, 2 is the hollow frustum-shaped metal component, 201 is the upper bottom surface platform, 202 is the through-hole, 203 is the threaded hole, and 204 is the O-ring groove.

[0059] (3) Preparation and testing of the gas isolation device for near-ambient-pressure X-ray photoelectron spectrometer:

[0060] Use epoxy resin AB glue to bond the side of the first silicon nitride film of the window pane with the ultra-small-size silicon nitride window obtained above onto the upper bottom surface platform of the hollow frustum-shaped metal component. The operation needs to be completed quickly within 15 minutes. Note that the AB glue should not block the silicon nitride window, and the silicon nitride window needs to be aligned with the through-hole of the hollow frustum-shaped metal component; after the operation is completed, place it in a dry, dust-free, and light-shielded environment to release internal stress to obtain the gas isolation device for near-ambient-pressure X-ray photoelectron spectrometer. As Figure 9 and Figure 10 shown Figure 9 This is a top view of the gas isolation device for near-ambient-pressure X-ray photoelectron spectrometer according to the present invention, Figure 10 This is a front view of the gas isolation device for near-ambient-pressure X-ray photoelectron spectrometer according to the present invention; wherein, 1 is the silicon nitride window pane, 2 is the hollow frustum-shaped metal component, 201 is the upper bottom surface platform, and 203 is the threaded hole.

[0061] Connect the above-obtained isolation device to the multi-stage differential pumping of the synchrotron near-ambient pressure photoelectron spectroscopy experimental station as the gas isolation device before the first-stage differential pumping, as Figure 11 shown Figure 11 Figure 1 is a schematic diagram of a conical hole test system equipped with the isolation device of the present invention. Specifically, through the threaded holes on the hollow frustum metal part, the isolation device is connected to the differential pumping using countersunk bolts and sealed with O-rings in the O-ring channels.

[0062] After testing, the ambient atmospheric pressure on the test day was 1010 mbar, and the pressure on the low-pressure side was measured to be 9.36×10 -3 mbar, indicating that the isolation device can achieve a low-pressure side pressure of 9.36×10 -3 mbar when the high-pressure side pressure is 1010 mbar, obtaining a gas isolation ability far exceeding that of the prior art. The device has the ability to obtain a working pressure more than 3 times higher than the current working pressure (30 mbar) when the ultra-high vacuum working environment on the side of the photoelectron detector is better than that of the prior art.

[0063] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. Gas isolation device for near-ambient pressure X-ray photoelectron spectrometer, characterized in that, Comprising: A hollow frustum-shaped metal component, the lower bottom surface of the hollow frustum-shaped metal component is open and the upper bottom surface is provided with a through hole; A double-sided silicon nitride-coated window plate provided with a through conical hole and connected to the upper bottom surface of the hollow frustum-shaped metal component, the large end of the through conical hole is connected to the through hole on the upper bottom surface of the hollow frustum-shaped metal component, and the aperture size of the small end of the through conical hole is 20 µm to 800 µm; The double-sided silicon nitride-coated window plate provided with a through conical hole is made from a double-sided silicon nitride-coated window plate, and the double-sided silicon nitride-coated window plate includes: A silicon wafer substrate; A first silicon nitride thin film and a second silicon nitride thin film respectively provided on both sides of the silicon wafer substrate.

2. The gas isolation device for near-ambient pressure X-ray photoelectron spectrometer according to claim 1, wherein, The aperture size of the small end of the through conical hole is 20 µm to 80 µm.

3. The gas isolation device for near-ambient pressure X-ray photoelectron spectrometer according to claim 1, wherein The aperture size of the large end of the through conical hole is 0.3 mm to 1.1 mm; The aperture size of the through hole on the upper bottom surface of the hollow frustum-shaped metal component is 0.5 mm to 2.75 mm.

4. The gas isolation device for near-ambient pressure X-ray photoelectron spectrometer according to any one of claims 1 to 3, characterized in that, The thicknesses of the first silicon nitride thin film and the second silicon nitride thin film are independently 80 nm to 120 nm; The thickness of the silicon wafer substrate is 200 µm to 500 µm.

5. The gas isolation device for near-ambient pressure X-ray photoelectron spectrometer according to any one of claims 1 to 3, characterized in that, The silicon wafer substrate is a 100 crystal orientation silicon wafer substrate.

6. The gas isolation device for near-ambient pressure X-ray photoelectron spectrometer according to claim 1, wherein The material of the hollow frustum-shaped metal component is Inconel 625 alloy.

7. The preparation method of the gas isolation device for near-ambient pressure X-ray photoelectron spectrometer according to any one of claims 1 to 6, characterized in that, Including the following steps: Gluing the double-sided silicon nitride-coated window plate provided with a through conical hole to the upper bottom surface of the hollow frustum-shaped metal component, such that the large end of the through conical hole is connected to the through hole on the upper bottom surface, and releasing internal stress to obtain the gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer.

8. The preparation method according to claim 7, characterized in that, The double-sided silicon nitride-coated window plate provided with a through conical hole is prepared by the following method: S1) Form a layer of photoresist on the surface of the first silicon nitride thin film of the double-sided silicon nitride-coated window plate, and photolithograph a photolithographic opening area on the photoresist that is the same as the large end of the through conical hole until the photolithographic opening area exposes the first silicon nitride thin film; S2) Perform reactive ion etching on the first silicon nitride thin film exposed by the photolithographic opening area until the photolithographic opening area exposes the silicon wafer substrate of the double-sided silicon nitride-coated window plate; S3) Perform deep silicon etching and wet etching on the silicon wafer substrate exposed by the photolithographic opening area in sequence until the photolithographic opening area exposes the second silicon nitride thin film of the double-sided silicon nitride-coated window plate; S4) Pierce the second silicon nitride thin film exposed by the photolithographic opening area to obtain the double-sided silicon nitride-coated window plate provided with a through conical hole.

9. Near-ambient-pressure X-ray photoelectron spectrometer, characterized in that, The detector region and the sample region thereof are isolated by the gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer according to any one of claims 1 to 6 or the gas isolation device for a near-ambient pressure X-ray photoelectron spectrometer obtained by the preparation method according to claim 7 or 8.

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