Ion source upper cover assembly and ion source device

Abstract

According to the ion source upper cover assembly and the ion source device provided by the invention, the shielding cage fixed in the ion source upper cover assembly can prevent deformation or damage caused by direct contact between the annular lamp filament and an external structure, and the structure of the annular lamp filament can effectively push hot electrons emitted by the annular lamp filament to the direction of the ionization chamber, so that the ionization effect is improved; according to the ion source device, the annular lamp filament is arranged, and the annular lamp filament, the ionization cylinder and the shielding cage are coaxial, so that electrons emitted by the annular lamp filament can move in a more uniform electric field, the probability that the electrons bombard sample gas is increased, and the ionization efficiency and the ionization efficiency stability of the ion source device are improved; and meanwhile, the ion source device has a wide-range emission current dynamic interval, relatively high anti-interference capability and a wide-range sensitivity linear area, and a total pressure focusing electrode structure in the ion source device can also monitor a vacuum degree value in a detected space in real time, so that the effects of protecting a filament and a vacuum system are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of analysis and detection, and in particular to an ion source upper cover component and an ion source device. Background Art

[0002] The residual gas analyzer based on quadrupole mass analyzer is a simple and compact mass spectrometer, which is often used for process atmosphere monitoring in semiconductor PVD, CVD, ETCH and other processes. It is mainly composed of ion source, mass analyzer, detector, supporting circuit and software.

[0003] The ion source is an indispensable and important part of the residual gas analyzer. Its function is to ionize the gas molecules and atoms in the monitoring atmosphere into ions, and then focus the ionized ions into an ion beam with a certain shape through the transmission lens and introduce it from the ion source to the entrance of the mass analyzer. There are many types of electron bombardment ion sources, the two most important types are closed and open ion sources. Among them, the open ion source is usually designed as an open grid structure, and all the functional components of the ion source are exposed to the same vacuum area.

[0004] The ion source is crucial to the residual gas analyzer. The quality of the ion source is directly related to the detection sensitivity, minimum detectable partial pressure, quantitative detection effect and even the quality detection range of the entire analyzer. In the prior art, the open ion source as part of the quadrupole mass spectrometer probe can be replaced as a whole as needed. In the case of filament failure, the filament cathode assembly can also be replaced separately. The filament of the filament cathode assembly is in direct contact with the external structure during storage and transportation, which can easily cause deformation or damage. In addition, the open ion source in the prior art either has insufficient ionization efficiency or insufficient ionization efficiency stability, poor anti-interference ability of the ion source, and a narrow linear range of ion source sensitivity, which affects the quality of process monitoring. Summary of the invention

[0005] In view of the shortcomings of the prior art described above, the object of the present invention is to provide an ion source upper cover assembly and an ion source device, which are used to solve the problems in the prior art that the filament of the open ion source filament cathode assembly is in direct contact with the external structure during storage and transportation, which is easy to cause deformation or damage, and the ionization efficiency is not high enough, the ionization efficiency is not stable enough, the anti-interference ability is poor, and the sensitivity linear range is narrow.

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

[0007] The filament substrate comprises a bottom surface and a top surface which are arranged opposite to each other, a hole is opened in the center of the filament substrate, and at least three mounting holes are arranged at preset positions on the filament substrate;

[0008] The filament cathode assembly comprises at least three filament electrodes arranged at intervals and at least two non-closed annular filaments; the filament electrodes pass through the mounting holes one by one and are insulated and fixedly connected to the filament substrate, and all the filament electrodes are arranged annularly around the center of the filament substrate; the annular filament is arranged at one end of the filament electrode exposed to the bottom surface of the filament substrate, and all the annular filaments are sequentially connected to all the filament electrodes arranged at intervals along the annular direction, and along the connection direction, the annular filament between the filament electrode at the head end and the filament electrode at the end end is not connected;

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

[0010] Optionally, the filament electrode includes a first filament electrode, a second filament electrode and a third filament electrode arranged at intervals, and the first filament electrode, the second filament electrode and the third filament electrode are arranged in a ring shape 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 filament, and the annular filament between the second filament electrode and the third filament electrode is formed into a second arc filament, the first arc filament and the second arc filament are symmetrically arranged, and the second filament electrode is formed as an electrode common end.

[0011] Optionally, the ion source upper cover assembly further comprises a ceramic tube, the ceramic tube is sleeved in the mounting hole, the filament electrode passes through a tube hole in the center of the ceramic tube, and is insulated and connected to the filament substrate.

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

[0013] The ceramic tube body is sleeved in the mounting hole;

[0014] The boss is connected to the ceramic tube body, extends from the mounting hole from the position 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 is engaged with the bottom surface of the filament substrate around the mounting hole.

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

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

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

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

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

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

[0021] Optionally, the opening rate of the hollow structure on the shielding cage is 30% to 85%, and the grid hole shape of the hollow structure includes one or more of a rectangle, a square and a regular hexagon.

[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 upper cover assembly as described in any one of the above items, which are coaxially insulated and fixed on the transition seat in sequence;

[0023] The ionization chamber comprises an ionization tube support plate and an ionization tube fixed on the ionization tube support plate, the side wall of the ionization tube is arranged as a hollow structure, the end of the ionization tube away from the ionization tube support plate is also arranged as a hollow structure, the end of the ionization tube connected to the ionization tube support plate is arranged as a fully open structure, the ionization tube support plate is a central opening plate, and the central hole of the ionization tube support plate is coaxially arranged with the ionization tube, the shielding cage of the ion source upper cover assembly is sleeved on the periphery of the ionization tube, and the annular filament is located on the periphery of the ionization tube and is coaxially arranged with the ionization tube;

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

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

[0026] A lead-out hole is provided at the center of the transition seat;

[0027] The center hole of the ionization tube 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 gradually reduced in size to form a lens group for focusing and extracting ionized ions in the ionization chamber.

[0028] Optionally, the diameter of the ionization tube is 8 mm to 9 mm, the opening rate of the hollow structure on the side wall of the ionization tube is 65% to 75%, and the grid hole shape of the hollow structure on the side wall of the ionization tube includes one or more of rectangle, square and regular hexagon.

[0029] Optionally, the diameter of the center hole of the ionization tube support plate is 3.5 mm to 4.5 mm, the diameter of the first lens hole of the extraction electrode is 2.5 mm to 3.5 mm, and the diameter of the second lens hole of the total pressure focusing electrode is 1.5 mm to 2.0 mm.

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

[0031] Optionally, a horn cone is provided at one end of the ionization cylinder support plate close to the ionization cylinder, the horn cone is provided above the center hole and concentrically with the center hole, and the horn cone extends inward in a cone shape from the surface of the ionization cylinder support plate in contact with the ionization cylinder.

[0032] Optionally, the opening rate of the hollow structure at one end of the ionization tube away from the ionization tube support plate is 65% to 75%, and the grid hole shape of the hollow structure includes one or more of a rectangle, a square and a regular hexagon.

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

[0034] The ion source upper cover assembly of the present invention is a part of the ion source device. When the annular filament fails, the ion source upper cover assembly can be replaced separately. During storage and transportation, the ion source upper cover assembly has a shielding cage to prevent the annular filament from directly contacting the external structure and causing deformation or damage, thereby protecting the annular filament.

[0035] The ion source device of the present invention can make the electric field formed between the annular filament and the ionization tube more uniform by setting the filament as an annular filament, and the annular filament, the ionization tube and the shielding cage are coaxially arranged, so as to ensure that the electrons emitted by the annular filament can move in a more uniform electric field, thereby improving the probability of electron bombardment of the sample gas, improving the ionization efficiency and ionization efficiency stability of the ion source device, and the coaxial arrangement of the annular filament, the ionization tube and the shielding cage of the present embodiment also has a wide range of emission current dynamic range, strong anti-interference ability and a wide range of sensitivity linear plateau, and can increase the emission current for degassing and exhaust treatment after the ion source device is contaminated. The ionization tube of the ionization chamber of the present embodiment is arranged at one end away from the ionization tube support plate as a hollow structure. Compared with the fully open structure, the hollow structure can make the ions in the ionization chamber move toward the analyzer, reduce their escape from the top of the ionization chamber to a certain extent, and play a role in further improving the ion trapping and extraction efficiency of the ion source device. In addition, the central hole of the ionization chamber support plate below the ionization chamber of the ion source device of this embodiment, the first lens hole of the extraction electrode and the second lens hole of the total pressure focusing electrode form a lens group with gradually decreasing size, which can focus ions into an ion beam with a certain shape and lead it out from the ion source device, wherein the total pressure focusing electrode structure not only participates in the formation of the focusing lens, but also serves as the monitoring of the total pressure ion current of the system. Under the condition that the electrodes of the ion source device are set with reasonable voltages, it also has good total pressure detection capabilities 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, and shut down the filament when the threshold is exceeded to protect the filament from damage caused by gas pressure shock. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 Shown is a schematic diagram of an ion source upper cover assembly of the present invention.

[0037] Figure 2 Shown is a side structural schematic diagram of the ion source upper cover assembly of the present invention.

[0038] Figure 3 It is a schematic cross-sectional structure diagram of a filament substrate and a filament cathode assembly in the ion source upper cover assembly of the present invention.

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

[0040] Figure 5 A schematic diagram of an ionization chamber of an ion source device of the present invention is shown.

[0041] Figure 6 The invention is shown along Figure 5 Schematic diagram of the longitudinal cross-section structure along the AA' direction.

[0042] Figure 7A schematic diagram showing an extraction electrode of an ion source device of the present invention is shown.

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

[0044] Fig. 9 A schematic diagram of a transition block of an ion source device of the present invention is shown.

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

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

[0047] Fig.12 The figure shows the relationship between the vacuum degree and sensitivity of the ion source device of the present invention.

[0048] Component number description

[0049] 1 Ion source cover assembly

[0050] 10 Filament substrate

[0051] 101 Bottom

[0052] 102 Top

[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 Ring Filament

[0059] 112-1 First arc filament

[0060] 112-2 Second arc filament

[0061] 113 Electrode body

[0062] 114 first boss portion

[0063] 114-1 Thread structure

[0064] 115 second boss portion

[0065] 12 Shielding Cage

[0066] 13 Ceramic gasket

[0067] 131 First Ceramic Gasket

[0068] 132 Second ceramic gasket

[0069] 133 elastic gasket

[0070] 15 Fixing nut

[0071] 16 Ceramic tube

[0072] 161 Ceramic tube body

[0073] 162 Boss

[0074] 2 Ionization chamber

[0075] 21 Ionization tube support plate

[0076] 211 Center hole

[0077] 22 Ionization Cylinder

[0078] 221 Trumpet cone

[0079] 3. Extraction electrode

[0080] 31 First lens hole

[0081] 4 Total pressure focusing electrode

[0082] 41 Second lens hole

[0083] 5 Transition seat DETAILED DESCRIPTION

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

[0085] See also Figures 1 to 12 It should be noted that the illustrations provided in this embodiment are only used to illustrate the basic concept of the present invention in a schematic manner, and the illustrations only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0086] This embodiment provides an ion source upper cover assembly 1, such as Figures 1 to 3As shown, the ion source upper cover assembly 1 includes: a filament substrate 10, a filament cathode assembly 11 and a shielding cage 12;

[0087] The filament substrate 10 comprises a bottom surface 101 and a top surface 102 which are arranged opposite to each other, the filament substrate 10 has a central opening, and at least three mounting holes are arranged at preset positions on the filament substrate 10;

[0088] The filament cathode assembly 11 includes at least three filament electrodes 111 arranged at intervals and at least two non-closed annular filaments 112; the filament electrodes 111 pass through the mounting holes one by one and are insulated and fixedly connected to the filament substrate 10, and all the filament electrodes 111 are arranged annularly around the center of the filament substrate 10; the annular filament 112 is arranged at one end of the filament electrode 111 exposed to the bottom surface 101 of the filament substrate 10, and all the annular filaments 112 are sequentially connected to all the filament electrodes 111 arranged at intervals along the annular direction, and along the connection direction, the annular filament 112 between the filament electrode 111 at the head end and the filament electrode 111 at the end is not connected;

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

[0090] The ion source upper cover assembly of this embodiment is a part of the ion source device. In the case of failure of the annular filament, the ion source upper cover assembly can be replaced separately. The ion source upper cover assembly has a shielding cage during storage and transportation to prevent the annular filament from directly contacting the external structure to cause deformation or damage, thereby protecting the annular filament. In addition, this embodiment can effectively push the thermal electrons emitted by the annular filament toward the ionization chamber by adopting the structure of the annular filament, thereby improving the ionization effect.

[0091] As an example, Figure 1As shown, the filament electrode 111 includes a first filament electrode 111-1, a second filament electrode 111-2 and a third filament electrode 111-3 which are arranged at intervals, and the first filament electrode 111-1, the second filament electrode 111-2 and the third filament electrode 111-3 are arranged in a circular direction 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 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 filament 112-2, the first arc filament 112-1 and the second arc filament 112-2 are symmetrically arranged, and the second filament electrode 111-2 is formed as an electrode common end. Preferably, the annular filament 112 can be a tungsten filament or an iridium filament plated with yttrium oxide. The diameter of the annular filament 112 is between 0.125 mm and 0.15 mm, the radius of the circular ring where the annular filament 112 is located is 9 mm to 10 mm, and the coating thickness of the iridium filament with coating is 40 μm to 60 μm. Preferably, in this embodiment, the first arc filament 112-1 and the second arc filament 112-2 are integrally formed. When the annular filament 112 is welded to the three filament electrodes 111, the annular filament 112 can be welded to the second filament electrode 111-2 with only one welding, thereby simplifying the welding process. Current is applied to the annular filament 112 through the filament electrode 111, so that the annular filament 112 reaches a very high temperature, thereby emitting thermal electrons. The first arc filament 112-1 and the second arc filament 112-2 are symmetrically arranged, so that the two arc filaments have similar electron emission efficiency, ensuring that when one arc filament fails, the other arc filament can be immediately activated and maintain good consistency, so that the performance of the ion source device is more stable. Under suitable operating voltage parameters and structural parameters of the ion source device, electrons can be distributed in the space of the entire ionization chamber, and the space of the ionization chamber is fully utilized to improve the ionization efficiency.

[0092] As an example, Figure 1 As shown, 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. Some openings (not fully shown) are also provided at preset positions outside the central opening of the filament substrate 10 to fix the filament substrate 10 or avoid electrode wires.

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

[0094] Furthermore, if Figure 3 As shown, the ceramic tube 16 includes a ceramic tube body 161 and a boss 162;

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

[0096] The boss 162 is connected to the ceramic tube body 161, extends from the mounting hole from the position 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 is engaged with the bottom surface 101 of the filament substrate 10 around the mounting hole.

[0097] The boss 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, reduces the sensitivity reduction problem caused by the volatilization of the annular filament 112 material and the reduction of surface resistance due to sample adhesion, and greatly improves the ionization stability of the ion source device.

[0098] Furthermore, if Figure 3 As shown, each of the filament electrodes 111 includes an electrode body 113, a first boss portion 114 and a second boss portion 115 in sequence from the top surface 102 to the bottom surface 101 of the filament substrate 10;

[0099] The first boss portion 114 is connected to a side of the electrode body 113 close to the filament substrate 10 and extends radially from the periphery of the electrode body 113. The first boss portion 114 passes through the ceramic tube 16 and extends from the ceramic tube 16 to a position flush with a surface of the boss 162 of the ceramic tube 16 away from the filament substrate 10.

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

[0101] Furthermore, if Figure 3As shown, a thread structure 114-1 is provided on the first boss portion 114 exposed to the top surface 102 of the filament substrate 10, and the thread structure 114-1 cooperates with the fixing nut 15 to fix the filament electrode 111 to the filament substrate 10. For example, Figure 2 As shown, a ceramic gasket 13 is also provided between the fixing nut 15 and the filament substrate 10. In this embodiment, Figure 2 and Figure 3 As shown, 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 by 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 that the filament electrode 111 is insulated from the filament substrate 10, which greatly improves the insulation of the filament electrode 111 from the filament substrate 10 and the shielding cage 12, so that even when the filament electrode 111 is working and the temperature of the filament electrode 111 and the ceramic tube 16 increases, the ceramic can still maintain excellent insulation. Furthermore, a step is formed between the ceramic tube 16 , the ceramic gasket 13 and the filament substrate 10 , which further increases the distance between the filament electrode 111 and the filament substrate 10 , and effectively reduces the impact of the volatilization of the filament material on the system performance.

[0102] The shielding cage 12 preferably has a diameter of 15 mm to 17 mm, a height of 12 mm to 13 mm and is coaxially arranged with the circle where the annular filament 112 is located, playing a dual role of uniformly distributing the repulsive 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%, and the shape of the grid holes of the hollow structure includes one or more of a rectangle, a square and a regular hexagon, which can be set according to actual needs.

[0103] like Figures 4 to 9 As shown, 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 the ion source upper cover assembly 1 as described above, which are coaxially insulated and fixed on the transition seat 5 in sequence;

[0104] like Figure 5As shown, the ionization chamber 2 includes an ionization tube support plate 21 and an ionization tube 22 fixed on the ionization tube support plate 21, the side wall of the ionization tube 22 is set as a hollow structure, the end of the ionization tube 22 away from the ionization tube support plate 21 is also set as a hollow structure, the end of the ionization tube 22 connected to the ionization tube support plate 21 is set as a full-open structure, the ionization tube support plate 21 is a central hole plate, and the central hole 211 of the ionization tube support plate 21 is coaxially arranged with the ionization tube 22, the shielding cage 12 of the ion source upper cover assembly 1 is sleeved on the periphery of the ionization tube 22, and the annular filament 112 is located at the periphery of the ionization tube 22 and is coaxially arranged with the ionization tube 22;

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

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

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

[0108] The center hole 211 of the ionization tube support plate 21, the first lens hole 31 of the extraction electrode 3 and the second lens hole 41 of the total pressure focusing electrode 4 are concentrically arranged and gradually reduced in size to form a lens group for focusing and extracting the ionized ions in the ionization chamber 2.

[0109] In this embodiment, the filament is arranged as a ring filament, and the ring filament, ionization tube and shielding cage are arranged coaxially, so that the electric field formed between the ring filament and the ionization tube can be more uniform, ensuring that the electrons emitted by the ring filament can move in a more uniform electric field, thereby increasing the probability of electron bombardment of the sample gas, and improving the ionization efficiency and ionization efficiency stability of the ion source device. In addition, the coaxial arrangement of the ring filament, ionization tube and shielding cage in this embodiment also has a wide range of emission current dynamic range, strong anti-interference ability and a wide range of sensitivity linear plateau, and the emission current can be increased to perform degassing and exhaust treatment after the ion source device is contaminated.

[0110] The end of the ionization tube of the ionization chamber of the present embodiment, which is away from the ionization tube support plate, is configured as a hollow structure. Compared with a fully open hole structure, the hollow structure can make the ions in the ionization chamber move toward the analyzer, thereby reducing their escape from the top of the ionization chamber to a certain extent, thereby further improving the ion trapping and extraction efficiency of the ion source device.

[0111] In addition, the central hole of the ionization chamber support plate below the ionization chamber of the ion source device of this embodiment, the first lens hole of the extraction electrode and the second lens hole of the total pressure focusing electrode form a lens group with gradually decreasing size, which can focus ions into an ion beam with a certain shape and lead it out from the ion source device, wherein the total pressure focusing electrode structure not only participates in the formation of the focusing lens, but also serves as the monitoring of the total pressure ion current of the system. Under the condition that the electrodes of the ion source device are set with reasonable voltages, it also has good total pressure detection capabilities 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, and the filament is shut down when the threshold is exceeded to protect the filament from damage caused by gas pressure shock.

[0112] The space where the ionization chamber 2 is located is used to ionize and store neutral atoms or molecules entering the space of the ionization cylinder 22, in order to ensure a moderate ionization space, the efficiency of electrons entering the space of 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 an example, Figure 5 and Figure 6 As shown, the ionization tube 22 is a cylindrical structure with hollowed-out side walls. The diameter of the ionization tube 22 is preferably controlled at 8 mm to 9 mm, slightly smaller than the diameter of the ring where the annular filament 112 is located. The height is controlled between 12 and 15 mm, slightly higher than the height of the shielding cage 12. The diameter of the ionization tube 22 is 8 mm to 9 mm, and the opening rate of the hollow structure on the side wall of the ionization tube 22 is 65% to 75%. The shape of the grid holes of the hollow structure on the side wall of the ionization tube 22 includes one or more of a rectangle, a square and a regular hexagon.

[0113] As an example, the opening rate of the hollow structure at one end of the ionization tube 22 away from the ionization tube support plate 21 is 65% to 75%, and the grid hole shape of the hollow structure includes one or more of a rectangle, a square and a regular hexagon. The hollow structure can make the ions in the ionization chamber move toward the analyzer, reduce their escape from the top of the ionization chamber to a certain extent, and play a role in further improving the ion trapping and extraction efficiency of the ion source device.

[0114] As an example, Figure 6 As shown, a horn cone 221 is provided at one end of the ionization tube support plate 21 close to the ionization tube 22, and the horn cone 221 is arranged above the center hole 211 and concentric with the center hole 211, and the horn cone 221 extends inward in a cone shape from the surface of the ionization tube support plate 21 in contact with the ionization tube 22, so that the ion extraction efficiency is not affected by the right angle at the connection between the ionization tube support plate 21 and the ionization tube 22, and the focusing effect of the ion extraction of the ion chamber 2 is further improved.

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

[0116] As an example, the filament substrate 10, the ionization tube 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 materials, and in order to improve the anti-pollution ability and weather resistance of the ion source device, the filament substrate 10, the ionization tube 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 tube 22 is coaxially arranged with the center hole 211 of the ionization tube support plate 21. As an example, during assembly, a positioning tool can be used to coaxially assemble the ionization tube 22, 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 tube support plate 21, so that ions move toward the analyzer without escaping from the top of the ionization chamber 2, which 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, improving the system ionization efficiency and enhancing the system sensitivity. On the basis of the above-mentioned ion source device size specifications, by calculating the radius of the annular filament 112, the influence of the distance between the annular filament 112 and the filament substrate 10 on the trajectory of the emitted electrons and the trajectory of the sample ions, the optimal diameter of the annular filament 112 and the optimal longitudinal height position of the annular filament 112 can be determined. Through simulation and experiments, based on the above ion source dimensions, the optimal diameter of the circular ring where the filament is located is 10 mm, and the annular filament 112 is located at the height of the middle position of the ionization tube 22 in the height direction.

[0118] The ion source device is assembled on the ion source test fixture for operation. The voltage of the ion source upper cover assembly 1 is set to 0V, the voltage of the electrode common terminal 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, the partial pressure and the total pressure of the ion source device are kept close to the sensitivity. When the potential of the total pressure focusing electrode 4 is 0V, the working voltage of the extraction electrode 3 has a large adjustable space. At the same time, the performance of the ion source device is greatly improved with the increase of the emission current, and the ion source cleaning under high emission can be achieved. Fig.10 and Fig.11 shown.

[0119] In addition, by assembling the ion source device onto an ion source test fixture for operation, it can be detected that the measurement efficiency of the total pressure and the partial pressure is equivalent within a wide range of vacuum degrees, and has good sensitivity linearity, such as Fig.12 shown.

[0120] In summary, the ion source upper cover assembly of the present invention is a part of the ion source device. When the annular filament fails, the ion source upper cover assembly can be replaced separately. The ion source upper cover assembly has a shielding cage during storage and transportation to prevent the annular filament from directly contacting the external structure and causing deformation or damage, thereby protecting the annular filament. In addition, the ion source upper cover assembly of the present invention can effectively push the thermal electrons emitted by the annular filament toward the ionization chamber by adopting the structure of the annular filament, thereby improving the ionization effect.

[0121] The ion source device of the present invention arranges the filament into an annular filament, and the annular filament, ionization tube and shielding cage are arranged coaxially, so that the electric field formed between the annular filament and the ionization tube is more uniform, and the electrons emitted by the annular filament can move in a more uniform electric field, thereby increasing the probability of electron bombardment of the sample gas, and improving the ionization efficiency and ionization efficiency stability of the ion source device. In addition, the coaxial arrangement of the annular filament, ionization tube 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, and the emission current can be increased to perform degassing and exhaust treatment after the ion source device is contaminated.

[0122] In addition, the central hole of the ionization chamber support plate below the ionization chamber of the ion source device of this embodiment, the first lens hole of the extraction electrode and the second lens hole of the total pressure focusing electrode form a lens group with a gradually reduced size, which can focus the ions into an ion beam with a certain shape and lead it out from the ion source device, wherein the total pressure focusing electrode structure, in addition to participating in the formation of the focusing lens, also serves as the monitoring of the total pressure ion current of the system. It is possible to monitor the vacuum value in the detected space in real time, and this information can be used for secondary calibration analysis with the measured value of the vacuum measuring equipment on the process line to obtain the quantitative analysis effect of the partial pressure monitoring values ​​of different residual gas analyzers. At the same time, the total pressure measuring electrode can also be configured with a certain threshold value, and when the threshold value is exceeded, the working filament and the vacuum pump group of the residual gas analyzer can be automatically shut down to protect the filament and the vacuum system. Therefore, the present invention effectively overcomes the various shortcomings in the prior art and has a high industrial utilization value.

[0123] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Anyone familiar with the art may 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 a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. An ion source upper cover assembly, characterized in that: The ion source upper cover assembly comprises: a filament substrate, a filament cathode assembly and a shielding cage; The filament substrate comprises a bottom surface and a top surface which are arranged opposite to each other, a hole is opened in the center of the filament substrate, and at least three mounting holes are arranged at preset positions on the filament substrate; The filament cathode assembly comprises at least three filament electrodes arranged at intervals and at least two non-closed annular filaments; the filament electrodes pass through the mounting holes one by one and are insulated and fixedly connected to the filament substrate, and all the filament electrodes are arranged annularly around the center of the filament substrate; the annular filament is arranged at one end of the filament electrode exposed to the bottom surface of the filament substrate, and all the annular filaments are sequentially connected to all the filament electrodes arranged at intervals along the annular direction, and along the connection direction, the annular filament between the filament electrode at the head end and the filament electrode at the end end is not connected; The shielding cage is fixed to the bottom surface of the filament substrate, the annular filament penetrates into the shielding cage and is coaxially arranged with the shielding cage, the side wall of the shielding cage is arranged as a hollow structure, and both ends of the shielding cage are arranged as a fully open structure.

2. The ion source upper 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 which are arranged at intervals, and the first filament electrode, the second filament electrode and the third filament electrode are arranged in a ring direction 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 filament, and the annular filament between the second filament electrode and the third filament electrode is formed into a second arc filament, the first arc filament and the second arc filament are symmetrically arranged, and the second filament electrode is formed as an electrode common end.

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

4. The ion source upper cover assembly according to claim 3, characterized in that: The ceramic tube comprises a ceramic tube body and a boss; The ceramic tube body is sleeved in the mounting hole; The boss is connected to the ceramic tube body, extends from the mounting hole from the position 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 is engaged with the bottom surface of the filament substrate around the mounting hole.

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

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

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

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

9. The ion source upper cover assembly according to claim 1, characterized in that: The opening rate of the hollow structure on the shielding cage is 30% to 85%, and the grid hole shape of the hollow structure includes one or more of a rectangle, a square and a regular hexagon.

10. An ion source device, characterized in that: The ion source device comprises: a transition seat and a total pressure focusing electrode, an extraction electrode, an ionization chamber and an ion source upper cover assembly as claimed in any one of claims 1 to 9, which are coaxially insulated and fixed on the transition seat in sequence; The ionization chamber comprises an ionization tube support plate and an ionization tube fixed on the ionization tube support plate, the side wall of the ionization tube is arranged as a hollow structure, the end of the ionization tube away from the ionization tube support plate is also arranged as a hollow structure, the end of the ionization tube connected to the ionization tube support plate is arranged as a fully open structure, the ionization tube support plate is a central opening plate, and the central hole of the ionization tube support plate is coaxially arranged with the ionization tube, the shielding cage of the ion source upper cover assembly is sleeved on the periphery of the ionization tube, and the annular filament is located on the periphery of the ionization tube and is coaxially arranged with the ionization tube; The lead-out electrode is a flat plate electrode with a first lens hole arranged at the center; The total pressure focusing electrode is a flat plate electrode with a second lens hole arranged at the center, and the size of the second lens hole is smaller than the size of the first lens hole; A lead-out hole is provided at the center of the transition seat; The center hole of the ionization tube 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 gradually reduced in size to form a lens group for focusing and extracting ionized ions in the ionization chamber.

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

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

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

14. The ion source device according to claim 10, characterized in that: A horn cone is provided at one end of the ionization tube support plate close to the ionization tube. The horn cone is provided above the center hole and concentrically with the center hole, and the horn cone extends inward in a cone shape from the surface of the ionization tube support plate in contact with the ionization tube.

15. The ion source device according to claim 10, characterized in that: The opening rate of the hollow structure at one end of the ionization tube away from the ionization tube support plate is 65% to 75%, and the grid hole shape of the hollow structure includes one or more of a rectangle, a square and a regular hexagon.

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