Ion source upper lid assembly and ion source device

Abstract

The application provides an ion source upper cover assembly and an ion source device. The fixed shielding cage in the ion source upper cover assembly can prevent the annular filament from being directly in contact with external structures to cause deformation or damage. The structure of the annular filament can effectively push the hot electrons emitted by the annular filament towards the ionization chamber, improve the ionization effect, and the ion source device is provided with the annular filament. The annular filament, the ionization cylinder and the shielding cage are coaxial, so that the electrons emitted by the annular filament can move in a more uniform electric field, thereby improving the probability of electron bombardment on the sample gas and improving the ionization efficiency and stability of the ion source device. Meanwhile, the ion source device has a wide range of emission current dynamic interval, strong anti-interference ability and wide range of sensitivity linear plateau area. The total pressure focusing electrode structure in the ion source device can also monitor the vacuum value in the detected space in real time, thereby playing a role in protecting the filament and the vacuum system.

Description

Ion source cover assembly and ion source device Technical Field

[0001] This invention relates to the field of analytical testing technology, and in particular to an ion source cover assembly and an ion source device. Background Technology

[0002] A residual gas analyzer based on a quadrupole mass analyzer is a simple and compact mass spectrometer commonly used for monitoring the process atmosphere in semiconductor PVD, CVD, ETCH, and other processes. It mainly consists of an ion source, a mass analyzer, a detector, supporting circuitry, and software.

[0003] An ion source is an indispensable component of a residual gas analyzer. Its function is to ionize gas molecules and atoms in the monitored atmosphere into ions, and then focus the ionized ions into an ion beam of a specific shape through a transmission lens before introducing it into the mass analyzer inlet. There are various types of electron impact ion sources, the two main types being closed and open ion sources. Open ion sources are typically designed with an open grid structure, where all functional components are exposed within the same vacuum region.

[0004] The ion source is crucial for residual gas analyzers. Its quality directly affects the analyzer's detection sensitivity, minimum detectable partial pressure, quantitative detection effect, and even the overall quality and detection range of the analyzer. In existing technologies, open-type ion sources, as part of a quadrupole mass spectrometer probe, can be replaced as a whole as needed. In the event of filament failure, the filament and cathode assembly can be replaced separately. However, during storage and transportation, the filament is in direct contact with external structures, making it susceptible to deformation or damage. Furthermore, existing open-type ion sources often suffer from insufficient ionization efficiency, instability in ionization efficiency, poor anti-interference capabilities, and narrow linear sensitivity ranges, all of which negatively impact process monitoring quality. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an ion source cover assembly and an ion source device to solve the problems of open ion source filament cathode assemblies in the prior art, such as the filament being in direct contact with the external structure during storage and transportation, which easily leads to deformation or damage, insufficient ionization efficiency, inadequate ionization efficiency stability, poor anti-interference ability, and narrow sensitivity linear range.

[0006] To achieve the above and other related objectives, the present invention provides an ion source cover assembly, the ion source cover assembly comprising: a filament substrate, a filament cathode assembly, and a shielding cage;

[0007] The filament substrate includes a bottom surface and a top surface disposed opposite to each other, the filament substrate has a central opening, and at least three mounting holes are provided at preset positions on the filament substrate;

[0008] The filament cathode assembly includes at least three filament electrodes spaced apart and at least two non-closed annular filaments; the filament electrodes pass through the mounting holes one-to-one and are insulated from and fixedly connected to the filament substrate, and all the filament electrodes are arranged circumferentially around the center of the filament substrate; the annular filaments are disposed at the ends of the filament electrodes exposed on the bottom surface of the filament substrate, and all the annular filaments are sequentially connected to all the spaced filament electrodes along the circumferential direction, and along the connection direction, the annular filaments between the filament electrode at the first end and the filament electrode at the last end are not connected;

[0009] The shielding cage is fixed to the bottom surface of the filament substrate, the annular filament extends into the shielding cage and is coaxially arranged with the shielding cage, the side wall of the shielding cage is configured as a hollow structure, and both ends of the shielding cage are configured as fully open structures.

[0010] Optionally, the filament electrode includes a first filament electrode, a second filament electrode, and a third filament electrode arranged at intervals, the first filament electrode, the second filament electrode, and the third filament electrode being arranged circumferentially around the center of the filament substrate; the annular filament between the first filament electrode and the second filament electrode is formed into a first arc-shaped filament, the annular filament between the second filament electrode and the third filament electrode is formed into a second arc-shaped filament, the first arc-shaped filament and the second arc-shaped filament are symmetrically arranged, and the second filament electrode is formed into a common electrode end.

[0011] Optionally, the ion source cover assembly further includes a ceramic tube, which is fitted into the mounting hole, and the filament electrode passes through the hole in the center of the ceramic tube and is insulated from the filament substrate.

[0012] Furthermore, the ceramic tube includes a ceramic tube body and a boss;

[0013] The ceramic tube body is fitted into the mounting hole;

[0014] The boss is connected to the ceramic tube body, extends from the mounting hole at the position where it is connected to the ceramic tube body, and protrudes from the bottom surface of the filament substrate; the cross-sectional area of ​​the boss is larger than the cross-sectional area of ​​the ceramic tube body, so that the edge of the boss engages with the bottom surface of the filament substrate around the mounting hole.

[0015] Furthermore, each of the filament electrodes includes, in sequence, an electrode body, a first boss portion, and a second boss portion in the direction from the top surface to the bottom surface of the filament substrate;

[0016] The first protrusion is connected to the side of the electrode body near the filament substrate and extends radially from the periphery of the electrode body. The first protrusion penetrates the ceramic tube and extends from inside the ceramic tube to a position flush with the surface of the protrusion of the ceramic tube away from the filament substrate.

[0017] The second protrusion is connected to the first protrusion. The second protrusion extends radially from the periphery of the electrode body, and the cross-sectional area of ​​the second protrusion is larger than that of the first protrusion, so that the second protrusion engages with the protrusion of the ceramic tube away from the surface of the filament substrate.

[0018] Furthermore, a threaded structure is provided on the first boss portion exposed above the top surface of the filament substrate, and the threaded structure cooperates with the fixing nut to fix the filament electrode to the filament substrate.

[0019] Furthermore, a ceramic washer is provided between the fixing nut and the filament substrate.

[0020] Optionally, the radius of the annular filament ring is 9mm to 10mm; the diameter of the shielding cage is 15mm to 17mm, and the height is 12mm to 13mm.

[0021] Optionally, the perforation rate of the hollow structure on the shielding cage is 30% to 85%, and the shape of the perforation of the hollow structure includes one or more of rectangles, squares, and regular hexagons.

[0022] This embodiment also provides an ion source device, the ion source device comprising: a transition seat and a total pressure focusing electrode, an extraction electrode, an ionization chamber, and an ion source cover assembly as described above, which are sequentially coaxially and insulatedly fixed on the transition seat;

[0023] The ionization chamber includes an ionization cylinder support plate and an ionization cylinder fixed on the ionization cylinder support plate. The side wall of the ionization cylinder is configured with a hollow structure. The end of the ionization cylinder away from the ionization cylinder support plate is also configured with a hollow structure. The end of the ionization cylinder connected to the ionization cylinder support plate is configured with a fully open structure. The ionization cylinder support plate is a centrally perforated plate, and the central hole of the ionization cylinder support plate is coaxially arranged with the ionization cylinder. The shielding cage of the ion source cover assembly is sleeved around the ionization cylinder. The annular filament is located around the ionization cylinder and is coaxially arranged with the ionization cylinder.

[0024] The lead-out electrode is a flat plate electrode with a first lens hole in the center;

[0025] The total pressure focusing electrode is a flat plate electrode with a second lens hole in the center, and the size of the second lens hole is smaller than the size of the first lens hole;

[0026] The transition seat is provided with an outlet hole at its center;

[0027] The central hole of the ionization cylinder support plate, the first lens hole of the extraction electrode, and the second lens hole of the total pressure focusing electrode are concentrically arranged and their sizes gradually decrease to form a lens group, which is used to focus and extract the ionized ions in the ionization chamber.

[0028] Optionally, the diameter of the ionization cylinder is 8mm to 9mm, the opening rate of the perforated structure on the side wall of the ionization cylinder is 65% to 75%, and the shape of the grid holes of the perforated structure on the side wall of the ionization cylinder includes one or more of rectangles, squares, and regular hexagons.

[0029] Optionally, the diameter of the central hole of the ionization cylinder support plate is 3.5mm to 4.5mm, the diameter of the first lens hole of the lead-out electrode is 2.5mm to 3.5mm, and the diameter of the second lens hole of the total pressure focusing electrode is 1.5mm to 2.0mm.

[0030] Optionally, the annular filament is located at the height of the middle position of the ionization cylinder in the height direction.

[0031] Optionally, the ionization cylinder support plate is provided with a horn-shaped conical opening at one end near the ionization cylinder. The horn-shaped conical opening is located above the central hole and is concentric with the central hole, and extends in a conical shape from the surface of the ionization cylinder support plate that is in contact with the ionization cylinder.

[0032] Optionally, the perforation rate of the hollow structure at the end of the ionizing cylinder away from the ionizing cylinder support plate is 65% to 75%, and the shape of the grid holes in the hollow structure includes one or more of rectangles, squares, and regular hexagons.

[0033] As described above, the ion source cover assembly and ion source device of the present invention have the following beneficial effects:

[0034] As part of the ion source device, the ion source cover assembly of the present invention can be replaced separately in the event of ring filament failure. The ion source cover assembly has a shielding cage during storage and transportation to prevent the ring filament from directly contacting the external structure and causing deformation or damage, thus protecting the ring filament.

[0035] The ion source device of this invention, by setting the filament as a ring filament and coaxially arranging the ring filament, ionization cylinder, and shielding cage, enables a more uniform electric field between the ring filament and the ionization cylinder. This ensures that electrons emitted by the ring filament can move in a more uniform electric field, thereby increasing the probability of electrons bombarding the sample gas and improving the ionization efficiency and stability of the ion source device. Furthermore, the coaxial arrangement of the ring filament, ionization cylinder, and shielding cage in this embodiment also provides a wide dynamic range of emission current, strong anti-interference capability, and a wide sensitivity linear plateau region. This allows for increased emission current for degassing and exhaust treatment after contamination of the ion source device. In this embodiment, the end of the ionization cylinder away from the ionization cylinder support plate is designed with a hollow structure. Compared to a fully open structure, this hollow structure allows ions within the ionization chamber to move towards the analyzer, reducing their escape from the top of the ionization chamber and further improving the ion trapping and extraction efficiency of the ion source device. Furthermore, in this embodiment, the central hole of the ionization chamber support plate below the ionization chamber, the first lens hole of the lead-out electrode, and the second lens hole of the total pressure focusing electrode form a lens group with gradually decreasing size. This allows ions to be focused into an ion beam of a specific shape and led out from the ionization chamber. The total pressure focusing electrode structure, in addition to participating in the formation of the focusing lens, also serves to monitor the total pressure ion current of the system. Under reasonable voltage conditions at each electrode of the ionization chamber, it also possesses good total pressure detection capability and a long linear range of total pressure sensitivity. This detection function can be used to set the amplitude threshold of the total pressure signal, preventing damage to the filament from pressure surges if the threshold is exceeded. Attached Figure Description

[0036] Figure 1 shows a schematic diagram of the ion source cover assembly of the present invention.

[0037] Figure 2 shows a side view of the ion source cover assembly of the present invention.

[0038] Figure 3 shows a schematic cross-sectional view of the filament substrate and filament cathode assembly in the ion source cover assembly of the present invention.

[0039] Figure 4 shows a schematic diagram of the ion source device of the present invention.

[0040] Figure 5 shows a schematic diagram of the ionization chamber of the ion source device of the present invention.

[0041] Figure 6 shows a schematic diagram of the longitudinal cross-sectional structure of the present invention along the AA' direction in Figure 5.

[0042] Figure 7 shows a schematic diagram of the extraction electrode of the ion source device of the present invention.

[0043] Figure 8 shows a schematic diagram of the total pressure focusing electrode of the ion source device of the present invention.

[0044] Figure 9 shows a schematic diagram of the transition seat of the ion source device of the present invention.

[0045] Figure 10 shows the relationship between the partial voltage sensitivity and the emission current of the ion source device of the present invention.

[0046] Figure 11 shows the relationship between the extraction electrode voltage and sensitivity of the ion source device of the present invention.

[0047] Figure 12 shows the relationship between the vacuum level and sensitivity of the ion source device of the present invention.

[0048] Component designation explanation

[0049] 1. Ion source cover assembly

[0050] 10 Filament substrate

[0051] 101 Bottom

[0052] 102 Top surface

[0053] 11 Filament Cathode Assembly

[0054] 111 Filament Electrode

[0055] 111-1 First filament electrode

[0056] 111-2 Second filament electrode

[0057] 111-3 Third filament electrode

[0058] 112 Circular Filament

[0059] 112-1 First Arc-shaped Filament

[0060] 112-2 Second Arc Filament

[0061] 113 Electrode Body

[0062] 114 First convex part

[0063] 114-1 Threaded Structure

[0064] 115 Second boss section

[0065] 12 Shielding cage

[0066] 13 Ceramic gaskets

[0067] 131 First Ceramic Gasket

[0068] 132 Second ceramic gasket

[0069] 133 Elastic Gasket

[0070] 15. Fixing nut

[0071] 16 Ceramic Tubes

[0072] 161 Ceramic tube body

[0073] 162 convex platform

[0074] 2 Ionization Chamber

[0075] 21 Ionization cylinder support plate

[0076] 211 Center Hole

[0077] 22 Ionization cylinder

[0078] 221 Trumpet-shaped mouth

[0079] 3. Lead-out electrodes

[0080] 31 First lens aperture

[0081] 4 Total Pressure Focusing Electrode

[0082] 41 Second lens hole

[0083] 5 Transition Seat Detailed Implementation

[0084] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0085] Please refer to Figures 1 to 12. It should be noted that the illustrations provided in this embodiment are only schematic representations of the basic concept of the present invention. Therefore, the illustrations only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components in the actual implementation. In the actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0086] This embodiment provides an ion source cover assembly 1, as shown in Figures 1 to 3. The ion source cover assembly 1 includes: a filament substrate 10, a filament cathode assembly 11, and a shielding cage 12.

[0087] The filament substrate 10 includes a bottom surface 101 and a top surface 102 disposed opposite to each other. The filament substrate 10 has a central opening and at least three mounting holes are provided at preset positions on the filament substrate 10.

[0088] The filament cathode assembly 11 includes at least three filament electrodes 111 spaced apart and at least two non-closed annular filaments 112; the filament electrodes 111 pass through the mounting holes one-to-one and are insulated from and fixedly connected to the filament substrate 10, and all the filament electrodes 111 are arranged circumferentially around the center of the filament substrate 10; the annular filaments 112 are disposed at one end of the filament electrodes 111 exposed on the bottom surface 101 of the filament substrate 10, and all the annular filaments 112 are sequentially connected to all the spaced filament electrodes 111 in the circumferential direction, and the annular filaments 112 between the first filament electrode 111 and the last filament electrode 111 are not connected in the connection direction;

[0089] The shielding cage 12 is fixed to the bottom surface 101 of the filament substrate 10. The annular filament 112 extends into the shielding cage 12 and is coaxially arranged with the shielding cage 12. The side wall of the shielding cage 12 is configured as a hollow structure, and both ends of the shielding cage 12 are configured as fully open structures.

[0090] In this embodiment, the ion source cover assembly is part of the ion source device. In the event of ring filament failure, the ion source cover assembly can be replaced separately. During storage and transportation, the ion source cover assembly has a shielding cage to prevent the ring filament from direct contact with external structures, thus preventing deformation or damage and protecting the ring filament. Furthermore, by employing a ring filament structure, this embodiment effectively pushes the thermionic electrons emitted by the ring filament towards the ionization chamber, improving the ionization effect.

[0091] As an example, as shown in Figure 1, the filament electrode 111 includes a first filament electrode 111-1, a second filament electrode 111-2, and a third filament electrode 111-3 spaced apart. The first filament electrode 111-1, the second filament electrode 111-2, and the third filament electrode 111-3 are arranged circumferentially around the center of the filament substrate 10. The annular filament 112 between the first filament electrode 111-1 and the second filament electrode 111-2 is formed into a first arc-shaped filament 112-1, and the annular filament 112 between the second filament electrode 111-2 and the third filament electrode 111-3 is formed into a second arc-shaped filament 112-2. The first arc-shaped filament 112-1 and the second arc-shaped filament 112-2 are symmetrically arranged, and the second filament electrode 111-2 is formed as a common electrode end. Preferably, the annular filament 112 can be a tungsten wire or an iridium wire coated with yttrium oxide. The diameter of the annular filament 112 is between 0.125 mm and 0.15 mm, the radius of the ring containing the annular filament 112 is 9 mm to 10 mm, and the coating thickness of the coated iridium filament is 40 μm to 60 μm. Preferably, in this embodiment, the first arc-shaped filament 112-1 and the second arc-shaped filament 112-2 are integrally formed. When welding the annular filament 112 to the three filament electrodes 111, only one welding operation is required to weld the annular filament 112 to the second filament electrode 111-2, thereby simplifying the welding process. Applying current to the annular filament 112 through the filament electrodes 111 causes the annular filament 112 to reach a very high temperature, thereby emitting thermionic electrons. The first arc-shaped filament 112-1 and the second arc-shaped filament 112-2 are symmetrically arranged, so that the two arc-shaped filaments have similar electron emission efficiencies. This ensures that if one arc-shaped filament fails, the other arc-shaped filament can be activated immediately and maintain good consistency, making the performance of the ion source device more stable. Under appropriate operating voltage and structural parameters, electrons can be distributed throughout the entire ionization chamber, making full use of the ionization chamber space to improve ionization efficiency.

[0092] As an example, as shown in Figure 1, the filament substrate 10 is disc-shaped and is used to fix the filament electrode 111 and the shielding cage 12. The filament substrate 10 has a central opening to facilitate the passage of sample gas. The filament substrate 10 also has some openings (not fully shown) at preset positions outside the central opening, which are used to fix the filament substrate 10 or to avoid the electrode wires.

[0093] As an example, as shown in Figure 3, the ion source cover assembly 1 also includes a ceramic tube 16, which is sleeved in the mounting hole. The filament electrode 111 passes through the hole in the center of the ceramic tube 16 and is insulated from the filament substrate 10.

[0094] Further, as shown in Figure 3, the ceramic tube 16 includes a ceramic tube body 161 and a boss 162;

[0095] The ceramic tube body 161 is sleeved inside the mounting hole;

[0096] The boss 162 is connected to the ceramic tube body 161, extends from the mounting hole from the position where it is connected to the ceramic tube body 161, and protrudes from the bottom surface 101 of the filament substrate 10; the cross-sectional area of ​​the boss 162 is larger than the cross-sectional area of ​​the ceramic tube body 161, so that the edge of the boss 162 engages with the bottom surface 101 of the filament substrate 10 around the mounting hole.

[0097] The protrusion 162 of the ceramic tube 16 between the filament electrode 111 and the filament substrate 10 increases the surface distance between the filament electrode 111 and the filament substrate 10, reducing the sensitivity reduction caused by the decrease in surface resistance due to the volatilization of the annular filament 112 material and sample adhesion, and greatly improving the ionization stability of the ion source device.

[0098] Further, as shown in FIG3, each of the filament electrodes 111 includes an electrode body 113, a first protrusion portion 114 and a second protrusion portion 115 in sequence from the top surface 102 to the bottom surface 101 of the filament substrate 10.

[0099] The first protrusion 114 is connected to the side of the electrode body 113 near the filament substrate 10 and extends radially from the periphery of the electrode body 113. The first protrusion 114 penetrates the ceramic tube 16 and extends from the inside of the ceramic tube 16 to a position flush with the surface of the protrusion 162 of the ceramic tube 16 away from the filament substrate 10.

[0100] The second protrusion 115 is connected to the first protrusion 114. The second protrusion 115 extends radially from the periphery of the electrode body, and the cross-sectional area of ​​the second protrusion 115 is larger than the cross-sectional area of ​​the first protrusion 114, so that the second protrusion 115 is engaged with the surface of the protrusion 162 of the ceramic tube 16 away from the filament substrate 10.

[0101] Further, as shown in FIG3, a threaded structure 114-1 is provided on the first boss portion 114 exposed on the top surface 102 of the filament substrate 10. The threaded structure 114-1 cooperates with the fixing nut 15 to fix the filament electrode 111 to the filament substrate 10. Exemplarily, as shown in FIG2, a ceramic gasket 13 is also provided between the fixing nut 15 and the filament substrate 10. In this embodiment, as shown in FIG2 and FIG3, the ceramic gasket 13 includes a first ceramic gasket 131, a second ceramic gasket 132, and an elastic gasket 133 in sequence from the top surface 102 of the filament substrate 10 to the fixing nut 15. The filament electrode 111 is fixed to the filament substrate 10 via the T-shaped step of the filament electrode 111, the ceramic tube 16, the ceramic gasket 13, the threaded structure 114-1 of the filament electrode 111, and the fixing nut 15. The ceramic tube 16 and the ceramic gasket 13 ensure insulation between the filament electrode 111 and the filament substrate 10, greatly improving the insulation between the filament electrode 111 and the filament substrate 10 and the shielding cage 12. This ensures that even when the temperature of the filament electrode 111 and the ceramic tube 16 rises during operation, the ceramic maintains excellent insulation. Furthermore, the step formed between the ceramic tube 16, the ceramic gasket 13, and the filament substrate 10 further increases the distance between the filament electrode 111 and the filament substrate 10, effectively reducing the impact on system performance caused by filament material volatilization.

[0102] The diameter of the shielding cage 12 is preferably 15mm to 17mm, and the height is 12mm to 13mm. It is coaxially arranged with the circle containing the annular filament 112, which serves the dual purpose of repelling the uniform distribution of the field strength and protecting the filament. The opening rate of the hollow structure on the side wall of the shielding cage 12 is 30% to 85%. The shape of the grid holes of the hollow structure includes one or more of rectangles, squares and regular hexagons, which can be set according to actual needs.

[0103] As shown in Figures 4 to 9, this embodiment also provides an ion source device, including: a transition seat 5 and a total pressure focusing electrode 4, an extraction electrode 3, an ionization chamber 2, and an ion source cover assembly 1 as described above, which are coaxially and insulatedly fixed on the transition seat 5 in sequence.

[0104] As shown in Figure 5, the ionization chamber 2 includes an ionization cylinder support plate 21 and an ionization cylinder 22 fixed on the ionization cylinder support plate 21. The side wall of the ionization cylinder 22 is configured with a hollow structure, and the end of the ionization cylinder 22 away from the ionization cylinder support plate 21 is also configured with a hollow structure. The end of the ionization cylinder 22 connected to the ionization cylinder support plate 21 is configured with a fully open structure. The ionization cylinder support plate 21 is a centrally perforated plate, and the central hole 211 of the ionization cylinder support plate 21 is coaxially arranged with the ionization cylinder 22. The shielding cage 12 of the ion source cover assembly 1 is sleeved around the ionization cylinder 22. The annular filament 112 is located around the ionization cylinder 22 and is coaxially arranged with the ionization cylinder 22.

[0105] As shown in Figure 7, the lead-out electrode 3 is a flat plate electrode with a first lens hole 31 at its center;

[0106] As shown in Figure 8, the total pressure focusing electrode 4 is a flat plate electrode with a second lens hole 41 at its center, and the size of the second lens hole 41 is smaller than the size of the first lens hole 31.

[0107] As shown in Figure 9, a lead-out hole is provided at the center of the transition seat 5;

[0108] The central hole 211 of the ionization cylinder support plate 21, the first lens hole 31 of the lead-out electrode 3, and the second lens hole 41 of the total pressure focusing electrode 4 are concentrically arranged and their sizes gradually decrease to form a lens group, which is used to focus and lead out the ionized ions in the ionization chamber 2.

[0109] This embodiment, by setting the filament as a ring filament and coaxially arranging the ring filament, ionization cylinder, and shielding cage, enables a more uniform electric field between the ring filament and the ionization cylinder. This ensures that the electrons emitted by the ring filament can move in a more uniform electric field, thereby increasing the probability of electrons bombarding the sample gas and improving the ionization efficiency and stability of the ion source device. Furthermore, the coaxial arrangement of the ring filament, ionization cylinder, and shielding cage in this embodiment also provides a wide dynamic range of emission current, strong anti-interference capability, and a wide range of sensitivity linear plateau. This allows for increased emission current for degassing and exhaust treatment after contamination of the ion source device.

[0110] In this embodiment, the end of the ionization cylinder away from the ionization cylinder support plate of the ionization chamber is set as a hollow structure. Compared with a fully open structure, this hollow structure allows the ions in the ionization chamber to move towards the analyzer, which reduces their escape from the top of the ionization chamber to a certain extent, and further improves the ion trapping and extraction efficiency of the ion source device.

[0111] Furthermore, in this embodiment, the central hole of the ionization chamber support plate below the ionization chamber, the first lens hole of the lead-out electrode, and the second lens hole of the total pressure focusing electrode form a lens group with gradually decreasing size. This allows ions to be focused into an ion beam of a specific shape and led out from the ionization chamber. The total pressure focusing electrode structure, in addition to participating in the formation of the focusing lens, also serves to monitor the total pressure ion current of the system. Under reasonable voltage conditions at each electrode of the ionization chamber, it also possesses good total pressure detection capability and a long linear range of total pressure sensitivity. This detection function can be used to set the amplitude threshold of the total pressure signal, preventing damage to the filament from pressure surges if the threshold is exceeded.

[0112] The space containing the ionization chamber 2 is used to ionize and store neutral atoms or molecules that enter the space of the ionization cylinder 22. To ensure a suitable ionization space, the efficiency of electrons entering the ionization cylinder 22, the intensity of ionization, and the efficiency of receiving the emission current, and to control the ability of the shielding cage 12 to pull out ions and the degree of ion dispersion, as shown in Figures 5 and 6, the ionization cylinder 22 is a cylindrical structure with hollowed-out sidewalls. The diameter of the ionization cylinder 22 is preferably controlled between 8mm and 9mm, slightly smaller than the diameter of the annular filament 112. The height is controlled between 12 and 15mm, slightly higher than the height of the shielding cage 12. The diameter of the ionization cylinder 22 is 8mm to 9mm, and the opening rate of the hollowed-out structure on the sidewall of the ionization cylinder 22 is 65% to 75%. The grid shape of the hollowed-out structure on the sidewall of the ionization cylinder 22 includes one or more of rectangles, squares, and regular hexagons.

[0113] As an example, the perforation rate of the hollow structure at the end of the ionization cylinder 22 away from the ionization cylinder support plate 21 is 65% to 75%, and the grid shape of the hollow structure includes one or more of rectangles, squares, and regular hexagons. This hollow structure allows ions in the ionization chamber to move towards the analyzer, reducing their escape from the top of the ionization chamber to a certain extent, and further improving the ion trapping and extraction efficiency of the ion source device.

[0114] As an example, as shown in Figure 6, the ionization cylinder support plate 21 is provided with a horn cone 221 at one end near the ionization cylinder 22. The horn cone 221 is located above the central hole 211 and is concentric with the central hole 211. The horn cone 221 extends inward in a cone shape from the surface of the ionization cylinder support plate 21 that contacts the ionization cylinder 22, so that the right angle at the connection between the ionization cylinder support plate 21 and the ionization cylinder 22 will not affect the ion extraction efficiency, and further improve the focusing effect of ion extraction in the ionization chamber 2.

[0115] As an example, the diameter of the lead-out hole of the transition seat 5 is 20mm, the diameter of the second lens hole 41 of the total pressure focusing electrode 4 is 1.5mm to 2.0mm, the diameter of the first lens hole 31 of the lead-out electrode 3 is 2.5mm to 3.5mm, the diameter of the central hole 211 of the ionization cylinder support plate 21 is 3.5mm to 4.5mm, and the size of the central opening of the filament substrate 10 is 9mm, which is equivalent to the diameter of the ionization cylinder 22 (9mm). Except for the ionization cylinder support plate 21 of the ionization chamber 2, which has a thickness of 1.5mm due to the design of a conical structure, the thickness of the filament substrate 10, the total pressure focusing electrode 4, and the lead-out electrode 3 are all set to 1mm. The ionization cylinder support plate 21, the lead-out electrode 3, the total pressure focusing electrode 4, and the transition seat 5 are all separated by ceramic insulation, with a separation height of 1mm to 1.5mm.

[0116] As an example, the filament substrate 10, the ionization cylinder support plate 21, the extraction electrode 3, the total pressure focusing electrode 4, and the transition seat 5 of the ion source device are all made of non-magnetic stainless steel. In order to improve the anti-pollution capability and weather resistance of the ion source device, the filament substrate 10, the ionization cylinder support plate 21, the extraction electrode 3, the total pressure focusing electrode 4, and the transition seat 5 of the ion source device are all passivated by gold plating process to reduce sample residual adsorption.

[0117] The ionization cylinder 22 and the ionization cylinder support plate 21 are coaxially arranged with the central hole 211. As an example, during assembly, a positioning fixture can be used to coaxially assemble the ionization cylinder 22 with the annular filament 112 and the shielding cage 12. The distance between the longitudinal height position of the annular filament 112 and the filament substrate 10 is not less than the distance between the longitudinal height position of the annular filament 112 and the ionization cylinder support plate 21, so that the ions move towards the analyzer and do not escape from the top of the ionization chamber 2. This further improves the ion trapping and extraction efficiency of the ion source device, while ensuring that the space of the ionization chamber 2 is fully utilized, thereby improving the system ionization efficiency and enhancing the system sensitivity. Based on the above-described dimensions of the ion source device, by calculating the influence of the radius of the annular filament 112 and the distance between the annular filament 112 and the filament substrate 10 on the trajectory of emitted electrons and the trajectory of sample ions, the optimal diameter of the annular filament 112 and the optimal vertical height position of the annular filament 112 can be determined. Through simulation and experiment, based on the above ion source dimensions, the optimal diameter of the annular filament is 10 mm, and the annular filament 112 is located at the height of the middle position of the ionization cylinder 22.

[0118] The ion source device is assembled onto the ion source testing fixture for operation. The voltage of the ion source cover assembly 1 is set to 0V, the voltage of the common terminal of the electrode is set to 180V, and the voltage of the ionization chamber 2 is set to 250V. That is, when the electron energy is maintained at 70eV, under the condition that the partial voltage and total voltage of the ion source device are close to the sensitivity, the working voltage of the lead-out electrode 3 has a large adjustable range when the potential of the total voltage focusing electrode 4 is 0V. At the same time, the performance of the ion source device is greatly improved with the increase of the emission current, and ion source cleaning under high emission can be achieved, as shown in Figures 10 and 11.

[0119] Furthermore, by assembling the ion source device onto an ion source testing fixture and operating it, it can be detected that the measurement efficiency of total pressure and partial pressure is comparable over a wide range of vacuum levels, and it has good sensitivity linearity, as shown in Figure 12.

[0120] In summary, the ion source cover assembly of the present invention, as part of the ion source device, can be replaced independently in the event of ring filament failure. During storage and transportation, the ion source cover assembly has a shielding cage to prevent the ring filament from direct contact with external structures, thus protecting it from deformation or damage. Furthermore, the ring filament structure of the ion source cover assembly of the present invention effectively pushes the thermionic electrons emitted by the ring filament towards the ionization chamber, improving the ionization effect.

[0121] The ion source device of the present invention, by setting the filament as a ring filament and coaxially arranging the ring filament, ionization cylinder, and shielding cage, can make the electric field formed between the ring filament and the ionization cylinder more uniform, ensuring that the electrons emitted by the ring filament can move in a more uniform electric field, thereby increasing the probability of electrons bombarding the sample gas, improving the ionization efficiency and stability of the ion source device. Furthermore, the coaxial arrangement of the ring filament, ionization cylinder, and shielding cage of the present invention also has a wide range of emission current dynamic range, strong anti-interference ability, and a wide range of sensitivity linear plateau region, which can increase the emission current for degassing and exhaust treatment after the ion source device is contaminated.

[0122] Furthermore, in this embodiment, the central hole of the ionization chamber support plate below the ionization chamber, the first lens hole of the lead-out electrode, and the second lens hole of the total pressure focusing electrode form a lens group with gradually decreasing size. This allows ions to be focused into an ion beam of a specific shape and led out from the ionization chamber. The total pressure focusing electrode structure, in addition to participating in the formation of the focusing lens, also serves to monitor the total pressure ion current of the system. It can monitor the vacuum level in the detected space in real time. This information can be used for secondary calibration analysis with the measurements from vacuum measuring equipment on the process line to analyze the quantitative analysis effect of different residual gas analyzer partial pressure monitoring values. Simultaneously, the total pressure measuring electrode can be configured with a certain threshold. When this threshold is exceeded, the working filament and the vacuum pump group of the residual gas analyzer can be automatically shut down, protecting the filament and the vacuum system. Therefore, this invention effectively overcomes the various shortcomings of the prior art and has high industrial applicability.

[0123] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. An ion source cover assembly, characterized in that, The ion source cover assembly includes: a filament substrate, a filament cathode assembly, and a shielding cage; the filament substrate includes a bottom surface and a top surface disposed opposite to each other, the filament substrate has a central opening, and at least three mounting holes are provided at preset positions on the filament substrate; the filament cathode assembly includes at least three filament electrodes and at least two non-closed annular filaments disposed at intervals; the filament electrodes pass through the mounting holes one by one and are insulated from and fixedly connected to the filament substrate, and all the filament electrodes are arranged circumferentially around the center of the filament substrate; the annular filaments are disposed at one end of the filament electrodes exposed on the bottom surface of the filament substrate, and all the annular filaments are sequentially connected to all the spaced filament electrodes along the circumferential direction, and the annular filaments between the filament electrodes at the first end and the filament electrodes at the last end are not connected along the connection direction; the shielding cage is fixed to the bottom surface of the filament substrate, the annular filaments extend into the shielding cage and are coaxially disposed with the shielding cage, the sidewalls of the shielding cage are configured as a hollow structure, and both ends of the shielding cage are configured as fully open structures.

2. The ion source cover assembly according to claim 1, characterized in that: The filament electrode includes a first filament electrode, a second filament electrode, and a third filament electrode arranged at intervals. The first filament electrode, the second filament electrode, and the third filament electrode are arranged circumferentially around the center of the filament substrate. The annular filament between the first filament electrode and the second filament electrode is formed into a first arc-shaped filament, and the annular filament between the second filament electrode and the third filament electrode is formed into a second arc-shaped filament. The first arc-shaped filament and the second arc-shaped filament are symmetrically arranged, and the second filament electrode is formed into a common electrode end.

3. The ion source cover assembly according to claim 1, characterized in that: The ion source cover assembly also includes a ceramic tube, which is fitted into the mounting hole. The filament electrode passes through the hole in the center of the ceramic tube and is insulated from the filament substrate.

4. The ion source cover assembly according to claim 3, characterized in that: The ceramic tube includes a ceramic tube body and a boss; the ceramic tube body is fitted into the mounting hole; the boss is connected to the ceramic tube body, extends from the mounting hole from the position where it is connected to the ceramic tube body, and protrudes from the bottom surface of the filament substrate; the cross-sectional area of ​​the boss is larger than the cross-sectional area of ​​the ceramic tube body, so that the edge of the boss engages with the bottom surface of the filament substrate around the mounting hole.

5. The ion source cover assembly according to claim 4, characterized in that: Each filament electrode includes, sequentially from the top surface to the bottom surface of the filament substrate, an electrode body, a first protrusion, and a second protrusion. The first protrusion is connected to the side of the electrode body near the filament substrate and extends radially from the periphery of the electrode body. The first protrusion penetrates the ceramic tube and extends from inside the ceramic tube to a position flush with the surface of the protrusion of the ceramic tube away from the filament substrate. The second protrusion is connected to the first protrusion and extends radially from the periphery of the electrode body. The cross-sectional area of ​​the second protrusion is larger than that of the first protrusion, so that the second protrusion engages with the surface of the protrusion of the ceramic tube away from the filament substrate.

6. The ion source cover assembly according to claim 5, characterized in that: A threaded structure is provided on the first boss portion exposed above the top surface of the filament substrate. The threaded structure cooperates with a fixing nut to fix the filament electrode to the filament substrate.

7. The ion source cover assembly according to claim 6, characterized in that: A ceramic washer is also provided between the fixing nut and the filament substrate.

8. The ion source cover assembly according to claim 1, characterized in that: The radius of the ring containing the annular filament is 9mm~10mm; the diameter of the shielding cage is 15mm~17mm and the height is 12mm~13mm.

9. The ion source cover assembly according to claim 1, characterized in that: The perforation rate of the hollow structure on the shielding cage is 30% to 85%, and the shape of the grid holes of the hollow structure includes one or more of rectangles, squares and regular hexagons.

10. An ion source device, characterized in that, The ion source device includes: a transition seat and a total pressure focusing electrode, an extraction electrode, an ionization chamber, and an ion source cover assembly as described in any one of claims 1 to 9, which are sequentially coaxially insulated and fixed on the transition seat; the ionization chamber includes an ionization cylinder support plate and an ionization cylinder fixed on the ionization cylinder support plate, the side wall of the ionization cylinder is configured with a hollow structure, the end of the ionization cylinder away from the ionization cylinder support plate is also configured with a hollow structure, the end of the ionization cylinder connected to the ionization cylinder support plate is configured with a fully open structure, the ionization cylinder support plate is a centrally perforated plate, and the central hole of the ionization cylinder support plate is coaxially arranged with the ionization cylinder, the shielding cage of the ion source cover assembly is sleeved around the ionization cylinder, the annular filament is located around the ionization cylinder and is coaxially arranged with the ionization cylinder; the ionization cylinder support plate is close to the ionization cylinder... One end of the cylinder is provided with a horn-shaped conical opening, which is located above and concentrically aligned with the central hole, and extends inward in a conical shape from the surface of the ionization cylinder support plate in contact with the ionization cylinder; the lead-out electrode is a flat plate electrode with a first lens hole in the center; the total pressure focusing electrode is a flat plate electrode with a second lens hole in the center, and the size of the second lens hole is smaller than the size of the first lens hole; the total pressure focusing electrode participates in the formation of the focusing lens and is used for monitoring the total pressure ion current of the system; the transition seat is provided with a lead-out hole in the center; the central hole of the ionization cylinder support plate, the first lens hole of the lead-out electrode, and the second lens hole of the total pressure focusing electrode are concentrically aligned and their sizes gradually decrease to form a lens group, which is used to focus and lead out the ionized ions in the ionization chamber.

11. The ion source device according to claim 10, characterized in that: The diameter of the ionization cylinder is 8mm to 9mm, the opening rate of the hollow structure on the side wall of the ionization cylinder is 65% to 75%, and the shape of the grid holes of the hollow structure on the side wall of the ionization cylinder includes one or more of rectangles, squares and regular hexagons.

12. The ion source device according to claim 10, characterized in that: The diameter of the central hole of the ionization cylinder support plate is 3.5mm~4.5mm, the diameter of the first lens hole of the lead-out electrode is 2.5mm~3.5mm, and the diameter of the second lens hole of the total pressure focusing electrode is 1.5mm~2.0mm.

13. The ion source device according to claim 10, characterized in that: The annular filament is located at the height of the middle position of the ionization cylinder in the vertical direction.

14. The ion source device according to claim 10, characterized in that: The perforation rate of the hollow structure at the end of the ionizing cylinder away from the ionizing cylinder support plate is 65% to 75%, and the shape of the grid holes of the hollow structure includes one or more of rectangles, squares and regular hexagons.

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