Emitter and electron gun
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-01-23
- Publication Date
- 2026-08-13
Smart Images
Figure JP2026002131_13082026_PF_FP_ABST
Abstract
Description
Emitter and electron gun
[0001] The present invention relates to an emitter and an electron gun.
[0002] Emitters that emit charged particles such as electrons and ions, and electron guns equipped with such emitters are used in microscopes, inspection devices, processing devices, and the like.
[0003] Patent Document 1 discloses an emitter having a shape in which a spherical surface is attached to the tip of a needle portion.
[0004] Japanese Unexamined Patent Application Publication No. 2023-62203
[0005] However, when an electron gun is attached to a device such as a microscope, it is necessary to appropriately adjust the alignment. For example, to adjust an electron gun attached to a device, first remove the extraction electrode from the device, and further remove the emission member that emits electrons from the emitter, and perform operations such as adjustment and replacement. After that, it is necessary to reassemble the electron gun and return it to the original device, and perform alignment adjustment of each member. The alignment adjustment of a plurality of members is a very complicated operation because the alignment of one member affects the alignment of other members, and a technique that can perform the operation efficiently has been demanded.
[0006] The present invention has been made in view of such a situation, and an object thereof is to provide a technique for efficiently adjusting an electron gun.
[0007] According to the present invention, the following technologies are realized: 1. An emitter comprising: an emission member that emits charged particles at its tip; a suppressor having a base to which the emission member is attached and to which a bias voltage is applied; and an insulating member having a cylindrical shape that houses the emission member inside, with a lead electrode joined to one end and the other end in contact with the base of the suppressor, wherein the insulating member is attached to the base by a removable fixing member. 2. The emitter according to 1, wherein the insulating member has a notch or through hole communicating the inside and outside within a range of 10 mm in the height direction from the joint portion with the lead electrode. 3. The emitter according to 1. or 2., wherein the insulating member has a protrusion projecting outward from its lower part, the base has a second surface facing the first surface below the protrusion, and the fixing member is cylindrical and houses the base and the protrusion inside, and presses the first surface against the second surface by pushing the third surface, which is the upper surface of the protrusion, downward. 4. The emitter according to 3., wherein the fixing member has a first screw groove on the inside, the base has a second screw groove on the outside corresponding to the first screw groove, and the first surface is pressed against the second surface by screwing the first screw groove and the second screw groove together. 5. An electron gun comprising the emitter according to 1. or 2., and a draw-out electrode provided facing the emission member of the emitter.
[0008] According to the present invention, it is possible to provide a technique for efficiently adjusting an electron gun.
[0009] This is a front view illustrating the configuration of an electron gun according to an embodiment. This is a cross-sectional view of the electron gun according to an embodiment. This is a partial cross-sectional view of the electron gun according to an embodiment. This is a diagram showing the lead-out electrode according to an embodiment. This is a front view of a suppressor according to an embodiment. This is a cross-sectional view of a suppressor according to an embodiment. This is a plan view of a suppressor according to an embodiment. This is a diagram showing an insulating member according to an embodiment. This is a diagram showing a fixing member according to an embodiment. This is a diagram illustrating the assembly procedure of an electron gun according to an embodiment.
[0010] Embodiments of the present invention will be described below with reference to the drawings. In all drawings, similar components are denoted by the same reference numerals, and their descriptions are omitted as appropriate.
[0011] <Overview> Figure 1 is a front view illustrating an electron gun 1 according to this embodiment. Figure 2 is a cross-sectional view of the electron gun 1, which briefly shows the configuration of the emission members 99 housed in the suppressor 40 and the circuit configuration connected to them to supply power. Figure 3 is a partial cross-sectional view illustrating the internal structure of the electron gun 1, which shows the lead electrode 10, insulating member 20, and fixing member 30 of Figure 1 as cross-sectional views.
[0012] <Electron Gun 1> Electron gun 1 is used, for example, in an electron beam apparatus. Examples of electron beam apparatus include X-ray generators, electron microscopes, semiconductor manufacturing equipment, analytical equipment (inspection equipment: e.g., electron probe microanalyzers), processing equipment (e.g., electron beam deposition equipment), etc.
[0013] The electron gun 1 has an emitter 2 and a lead electrode 10. The lead electrode 10 is provided at the tip of the emitter 2 (the upper tip in Figure 1) and facing the emission member 99 housed in the emitter 2. The lead electrode 10 and the emitter 2 are fixed together by a fixing part 70.
[0014] As will be described in detail later, the pull-out electrode 10 is joined to the insulating member 20. The pull-out electrode 10 and the insulating member 20 are attached to the suppressor 40, which houses the discharge member 99, by the insulating member 20 and a removable fixing member 30. Therefore, even when removing the pull-out electrode 10 and the insulating member 20 from the suppressor 40, for example, when adjusting or replacing the alignment of the discharge member 99, the pull-out electrode 10 and the insulating member 20 can be removed and attached as a single unit. Thus, the suppressor 40 and the discharge member 99 can be easily replaced and adjusted. For example, when a device such as a microscope is installed at the customer's site, conventionally, it was necessary to go to the installation site and adjust the pull-out electrode 10 and the insulating member 20, which was a lot of trouble. However, with the configuration of this embodiment, the pull-out electrode 10 and the insulating member 20 are fixed in advance, so on-site adjustment is unnecessary. A detailed explanation follows below.
[0015] Electron gun 1 can be used as a Schottky electron gun, for example. Electron gun 1 is connected to first to third power supplies 64 to 66, for example. The operation of electron gun 1 will be described later, along with a description of the configuration of the emission member 99.
[0016] <Drawer Electrode 10> Figure 4 shows the drawer electrode 10. Figure 4(a) is a plan view, Figure 4(b) is a bottom view, and Figure 4(c) is a cross-sectional view taken along X-X' in Figure 4(b).
[0017] The extraction electrode 10 is joined to the upper end of the emitter 2, more specifically to the upper end surface 25 of the insulating member 20, by a fixing part 70, and is used to provide an electric field for emitting electrons from the emission member 99. When electrons are emitted, the extraction electrode 10 has a positive potential relative to the suppressor 40. The "joining" by the fixing part 70 refers to a state in which the parts cannot be disassembled without destruction, more specifically, a state in which they are joined via a joining material, such as brazing or shrink fitting. From the viewpoint of ensuring good joining by the fixing part 70 and preventing damage due to thermal stress, it is preferable that the extraction electrode 10 and the insulating member 20 are made of materials with similar coefficients of thermal expansion. For example, if the insulating member 20 is made of hard glass such as Kovar glass, it is preferable that the extraction electrode 10 be made of metal such as Kovar alloy (Fe-Ni-Co alloy). Titanium alloy can also be used as the material for the extraction electrode 10. Alumina can also be used as the material for the insulating member 20. When fixed by screws, the drawer electrode 10 is prone to loosening or displacement due to thermal stress caused by the heat generated in the electrode. However, by joining the drawer electrode 10 to the insulating member 20, such concerns can be avoided.
[0018] The extraction electrode 10 has a disc-shaped electrode body 11 with an outer diameter D11, a recess 14 provided in the center of the upper surface 12 of the electrode body 11, a cylindrical protrusion 18 provided in the center of the lower surface 13, a flat portion 15 with a thickness T15 provided on the outside of the protrusion 18, and four ribs 16 protruding downward from the flat portion 15.
[0019] The recess 14 is concave in a mortar shape and has a through hole 17 in the center. Electrons emitted from the emission member 99 pass through the through hole 17.
[0020] The four ribs 16 are arranged in the same arc shape at equal intervals in the circumferential direction when viewed from below, for example, as shown in Figure 4(b). The height of the ribs 16 and the height of the protrusions 18 are set to the same height T16. The ribs 16 are joined to the upper end surface 25 of the insulating member 20 via the fixing portion 70 when the lead electrode 10 and the insulating member 20 are connected.
[0021] By providing the rib 16, that is, by creating a recessed space between the rib 16 and the protrusion 18, when brazing is used as the fixing part 70, it is possible to prevent the brazing material from flowing into the through hole 17, which will be the electron emission part, during the brazing work.
[0022] <Emitter 2> Emitter 2 is, for example, an electron emitter that emits electrons as charged particles. However, emitter 2 may also be an emitter that emits ions as charged particles. In this embodiment, a thermal field emitter (TFE) is given as an example of emitter 2. In other words, emitter 2 can also be said to be a Schottky emitter. In this case, emitter 2 emits electrons by heating the emission member 99 housed inside and applying an electric field. However, emitter 2 is not limited to a thermal field emitter, but can be used with various types of emitters used in various electron guns, for example, a cold field emitter (CFE) type emitter or a field emission type emitter.
[0023] In this embodiment, the emitter 2 includes a suppressor 40, an insulating member 20, a fixing member 30, and a discharge member 99. The discharge member 99 is housed inside the suppressor 40.
[0024] <Emission Member 99> As shown in Figure 2, the emission member 99 comprises a tip 101, a filament 102, a base 103, a first terminal 104, and a second terminal 105. Charged particles are emitted from the tip 101 towards the upper lead electrode 10 shown in the figure, and are emitted to the outside through the through hole 17 of the lead electrode 10.
[0025] The tip 101 is fixed to the filament 102. The tip 101 may also be fixed to the filament 102 via a conductive member. The filament 102 is used to heat the tip 101. The discharge member 99 may have a single filament 102 or may have multiple filaments 102.
[0026] The constituent material of the filament 102 can be a material that has heat resistance and conductivity. Examples of constituent elements of the filament 102 include tungsten, rhenium, molybdenum, platinum, aluminum, silicon, potassium, etc. The filament 102 may be a tungsten filament, or it may be a tungsten-rhenium (tungsten-rhenium alloy) filament.
[0027] The diameter of the filament 102 can be, for example, 1 μm to 500 μm, from the viewpoint of easily ensuring the strength necessary to support the tip 101, or from the viewpoint of easily increasing the resistance of the filament 102 and suppressing power consumption.
[0028] The base 103 is made of an insulating material such as glass, resin, or ceramic, and has a cylindrical shape. The shape of the base 103 is not limited to a cylindrical shape; it may also be a non-cylindrical shape, such as a semi-cylindrical shape (a so-called kamaboko shape). The base 103 is housed in a housing section 52 (first housing section 52a) formed inside the suppressor 40. As will be described later, the outer diameter of the base 103 is set to be the same as or slightly smaller than the inner diameter D52a of the housing section 52 (first housing section 52a), and it is fastened with screws using the through hole 47 of the lower base 42.
[0029] The first terminal 104 and the second terminal 105 form a terminal pair. The first terminal 104 and the second terminal 105 are spaced apart from each other and pass through the base 103.
[0030] In the example shown in Figure 2, one end of the filament 102 is connected to the first terminal 104, and the other end of the filament 102 is connected to the second terminal 105. A second power supply 65 is connected between the first terminal 104 and the second terminal 105, and by passing current through the second terminal 105, the filament 102, and the first terminal 104, the filament 102 is heated, and furthermore, the tip 101 is heated. The distance between the first terminal 104 and the second terminal 105 is preferably 0.1 mm or more from the viewpoint of suppressing inter-terminal discharge, and preferably 10 mm or less from the viewpoint of making it easier to miniaturize the emission member 99, i.e., the emitter 2. The base 103 is fixed inside the suppressor 40, more specifically in the first housing section 52a.
[0031] A positive voltage V is applied to the extraction electrode 10, with the potential of the first terminal 104 of the discharge member 99 as the reference. ｅｘ The first power supply 64 is connected to apply the voltage. If the emitter 2 is a field emission type emitter that emits positive ions (such as Ga+), a negative voltage is applied to the extraction electrode 10.
[0032] The second power supply 65 is a power supply for heating the chip 101 of the discharge member 99. Current I from the second power supply 65 ｆ The second power supply 65 is connected to the first terminal 104 and the second terminal 105 so that current flows through the filament 102. While current is flowing through the filament 102, the first terminal 104 has a positive potential relative to the second terminal 105.
[0033] The third power supply 66 supplies voltage V to the suppressor 40. ｂ This is a power supply for applying a negative voltage V to the suppressor 40, with the potential of the first terminal 104 as the reference. ｂ The third power supply 66 is connected to the suppressor 40 to apply the power.
[0034] The electron gun 1 may further include an accelerating electrode (not shown) facing the extraction electrode 10 at a position opposite to the suppressor 40, with reference to the extraction electrode 10. In this case, the extraction electrode 10 is positioned between the suppressor 40 and the accelerating electrode. The accelerating electrode can be used to accelerate electrons emitted from the emission member 99 (more specifically, the tip 101). The accelerating electrode may have a through-hole through which electrons emitted from the tip 101 pass. When electrons are emitted, the accelerating electrode may have a positive potential with reference to the potential of the extraction electrode 10.
[0035] A power supply is connected to the accelerating electrode to apply a voltage to it, and a positive voltage is output to the accelerating electrode with the potential of the extraction electrode 10 as a reference.
[0036] <Suppressor 40> Figure 5 is a front view of the suppressor 40. Figure 6 is a cross-sectional view of the suppressor 40. Figure 7 is a plan view of the suppressor 40. The suppressor 40 is made of metal and functions as an electrode that applies a bias voltage to the emission member 99. The suppressor 40 can be used to suppress the emission of charged particles from the side of the tip 101 or the filament 102 of the emission member 99.
[0037] The suppressor 40 has a tubular shape with a closed upper end that extends vertically as shown in the figure. However, as will be described later, a through hole 51 is provided in the center of the upper end through which the tip of the tip 101 protrudes. More specifically, the suppressor 40 integrally comprises a base 41, a neck portion 44, a tip cylindrical portion 45, and a tip conical portion 46, extending from the bottom to the top. Inside the base 41 is a housing portion 52, which is a space for housing the discharge member 99.
[0038] As shown in Figures 2 and 3, when the insulating member 20 is attached by the fixing member 30, the upper part of the suppressor 40 (upper base 43, neck portion 44, tip cylindrical portion 45, tip conical portion 46) is housed inside the insulating member 20 and the fixing member 30, while the lower part of the suppressor 40, the lower base 42, is not housed inside the insulating member 20 and the fixing member 30 and is exposed.
[0039] The pedestal 41 has a lower pedestal 42 on the lower side and an upper pedestal 43 on the upper side as shown in the figure. A groove 59 extending in the circumferential direction is formed between the lower pedestal 42 and the upper pedestal 43. The lower pedestal 42 has an outer diameter D42 and a thickness T42. The upper pedestal 43 has an outer diameter D43 and a thickness T43. The groove 59 has an outer diameter D59 and a thickness T59.
[0040] In the pedestal 41, the outer diameters of the lower pedestal 42, the upper pedestal 43, and the groove 59 have a relationship of D42 > D43 > D59. In other words, in a top view, the lower pedestal 42 is larger than the upper pedestal 43. The thickness T41 of the pedestal 41 is the sum of the thicknesses of the lower pedestal 42, the upper pedestal 43, and the groove 59 (T42 + T43 + T59).
[0041] The lower pedestal 42 is a tubular part. Through holes 47 that communicate the inside and outside are provided at three locations on the circumferential surface of the lower pedestal 42 at 120-degree intervals. The through holes 47 are used to screw and align the discharge member 99 (more specifically, the base 103) housed inside the suppressor 40.
[0042] The upper pedestal 43 is a tubular part. An outer screw groove 48 is provided on the outer peripheral surface of the upper pedestal 43. The outer screw groove 48 is divided into three equal parts in the circumferential direction, and the part where the outer screw groove 48 is not provided is a recess 48a recessed inward. The outer screw groove 48 is screwed with the inner screw groove 38 of the fixing member 30.
[0043] The upper surface 43a of the upper pedestal 43 is an annular flat surface (second surface) provided around the neck portion 44 provided at the center. When the insulating member 20 described later is attached to the suppressor 40 by the fixing member 30, the upper surface 43a faces and presses against the lower end surface 26 (first surface) of the convex portion 22 of the insulating member 20.
[0044] The neck portion 44 is a tubular part that extends upward at the center of the upper surface 43a of the upper pedestal 43. The neck portion 44 has an outer diameter D44 and a thickness T44. The outer diameter D44 of the neck portion 44 is smaller than the outer diameter D43 of the upper pedestal 43.
[0045] The tip cylinder part 45 is a tubular part that extends above the neck part 44. The tip cylinder part 45 has an outer diameter D45 and a thickness T45. The outer diameter D45 is slightly smaller than the outer diameter D44 of the neck part 44. Note that the neck part 44 and the tip cylinder part 45 may be regarded as a single part with the same outer diameter.
[0046] The tip cone part 46 is a part in the shape of a cone (truncated cone) with its tip cut off by a horizontal plane, which extends above the tip cylinder part 45. As shown in FIG. 2, at the center of the circular upper end face 55 cut off at the tip, there is a through hole 51 that communicates with the accommodation part 52 (the second accommodation part 52b), which is the internal space of the suppressor 40. In the through hole 51, the tip 101 of the discharge member 99 is arranged so as to penetrate vertically. The through hole 51 and the tip 101 are spaced apart.
[0047] Further, the tip cone part 46 is provided with a plurality (here, three) of through holes, namely tip window holes 49, through which the state of the tip 101 of the discharge member 99 can be visually recognized.
[0048] The accommodation part 52 is a space provided inside the suppressor 40, and the discharge member 99 is accommodated therein. The accommodation part 52 integrally has a lower first accommodation part 52a and an upper second accommodation part 52b.
[0049] The first accommodation part 52a is a space generally formed inside the pedestal 41 (the lower pedestal 42 and the upper pedestal 43), and the base 103 of the discharge member 99 is attached thereto. The inner diameter D52a of the first accommodation part 52a is slightly (for example, about several tens of μm) larger than the outer diameter of the base 103, so that the base 103 can be smoothly accommodated in the first accommodation part 52a. Also, since a slight gap is generated between the first accommodation part 52a and the base 103, as described above, they are fixed by screws.
[0050] The second housing section 52b is located above the first housing section 52a in the figure and is a space formed generally inside the neck section 44, the tip cylindrical section 45, and the tip conical section 46. The second housing section 52b accommodates, for example, the filament 102 and tip 101 that extend above the base 103. The inner diameter D52b of the second housing section 52b is smaller than the inner diameter D52a of the first housing section 52a, and for example, is small enough that the filament 102 of the discharge member 99 housed inside does not come into contact with it.
[0051] <Insulating Member 20> Figure 8 shows the insulating member 20, where Figure 8(a) is a front view, Figure 8(b) is a cross-sectional view, and Figure 8(c) is a plan view. The insulating member 20 is a cylindrical member that is positioned on the upper part of the base 41 (more specifically, the upper base 43) of the suppressor 40, and houses the neck portion 44, the tip cylindrical portion 45, and the tip conical portion 46 of the suppressor 40 inside. The lower end surface 26 of the insulating member 20 abuts against the upper surface 43a of the upper base 43, and the lower end surface 26 is pressed against the upper surface 43a of the upper base 43 by the fixing member 30.
[0052] The insulating member 20 is a cylindrical member made of an insulating material such as glass. The insulating member 20 has a cylindrical body 21, a protrusion 22, and a notch 29. The cylindrical body 21 is a cylindrical portion that extends in the vertical direction. The protrusion 22 is a portion that protrudes outward at the lower part of the cylindrical body 21, and is an annular portion with a rectangular cross-section that encircles the lower circumferential surface of the cylindrical body 21. The upper surface of the protrusion 23, which is the upper surface of the protrusion 22, is in contact with and pressed against the inner upper surface 34 of the fixing member 30 when the fixing member 30 presses the insulating member 20 against the suppressor 40. In addition, the inner diameter D28 of the cylindrical body 21 is set to a dimension that fits with a small clearance against the outer diameter D44 of the neck portion 44 of the suppressor 40. As a result, by simply inserting the insulating member 20 into the suppressor 40, the central axis of the lead electrode 10 can be precisely aligned with the central axis of the suppressor 40 (the axis of the tip 101) (it is automatically aligned).
[0053] The upper part of the cylindrical body 21 is provided with a notch 29 recessed downward from the upper end surface 25 by a predetermined depth T29. Four notches 29 are provided at equal intervals in the circumferential direction. The portion without notches 29, i.e., the upper end surface 25, is joined to the rib 16 of the aforementioned lead electrode 10 by the fixing portion 70. The predetermined depth T29 of the notch 29 is, in other words, the length in the height direction from the joining portion with the lead electrode 10 (in other words, the upper end surface 25), and is 10 mm as an example.
[0054] The notch 29 makes it easier to visually inspect the internal state of the upper part of the insulating member 20, in other words, the state near the tip cone portion 46 of the suppressor 40. As a result, it becomes easier to understand the state of the tip 101 of the discharge member 99 housed in the suppressor 40. For example, if the tip 101 is worn, damaged, or deformed, the discharge member 99 will need to be replaced or adjusted. The notch 29 allows for proper understanding of the timing of replacement or repair. Alternatively, instead of the notch 29, a through hole may be provided in the same range as the predetermined depth T29 (i.e., a range of 10 mm from the upper end surface 25). The predetermined depth T29 is set considering the visibility and strength of the discharge member 99 (especially the tip 101), but is preferably 7 mm or less, and more preferably 5 mm or less. For example, if the notch 29 is too far down, it may be impossible to check the state of the tip 101, which could hinder the assembly of the suppressor 40 and the lead electrode 10. Furthermore, if the notch 29 itself is large, the risk of foreign matter contamination increases, and it may become difficult to maintain the temperature of the emitter 2.
[0055] <Fixing Member 30> Figure 9 shows the fixing member 30. Figure 9(a) is a front view, Figure 9(b) is a cross-sectional view, and Figure 9(c) is a top view.
[0056] The fixing member 30 is a cylindrical (or socket-shaped) member with a bottom at the top. The fixing member 30 has a cylindrical body 31 and a bottomed top surface 32. The circumferential surface of the cylindrical body 31 is provided with a through hole 39 that connects the inside of the cylinder 36 to the outside. The through hole 39 has the function of discharging gas generated inside the emitter 2 to the outside.
[0057] The internal space 36 of the cylindrical body 31 has the same inner diameter D38 from the bottom surface 33 (bottom opening) to the inner top surface 34 of the top surface 32, and an internal screw groove 38 is formed on its inner circumferential surface. The internal screw groove 38 is screwed into an external screw groove 48 provided on the outer circumferential surface of the upper base 43 of the suppressor 40.
[0058] An upper opening 37 is provided on the upper surface 32, allowing the inside of the cylinder 36 to communicate with the outside. The inner diameter D37 of the upper opening 37 is smaller than the inner diameter D38. When the fixing member 30 fastens the insulating member 20 and the suppressor 40, the inner upper surface 34, which is the area from the inner circumferential surface to the upper opening 37, is pressed against the upper surface 23 of the protrusion 22 of the insulating member 20. The fixing force between the insulating member 20 and the suppressor 40 can be adjusted by adjusting the amount of screw tightening of the fixing member 30.
[0059] Although screw fitting was given as an example of a means of fastening the insulating member 20 and the suppressor 40 by the fixing member 30, this is not the only option, and other methods such as snap-fit fitting (a structure in which one protrusion (holding part) is fitted into the recess on the receiving side using the elasticity of the material) or fitting using pins and pin holes may also be used. Furthermore, these fitting structures may be used in combination.
[0060] <Relationship of Outer Diameters of Components of Electron Gun 1> When viewed from above, the pull-out electrode 10, insulating member 20, and fixing member 30 do not protrude from the suppressor 40. That is, the outer diameter of the suppressor 40 is larger than the outer diameters of the pull-out electrode 10, insulating member 20, and fixing member 30. Here, the pull-out electrode 10, insulating member 20, fixing member 30, and suppressor 40 have a concentric (approximately the same central axis) circular shape when viewed from above. The pull-out electrode 10, insulating member 20, fixing member 30, and suppressor 40 are arranged in this order from the tip side when assembled, as shown in Figures 1 to 3. The outer diameter of each component refers to the maximum outer diameter of each component. In the configuration illustrated in this embodiment, the outer diameter of the pull-out electrode 10 is the outer diameter D11 of the electrode body 11. The outer diameter of the insulating member 20 is the outer diameter D22 of the protrusion 22. The outer diameter of the fixing member 30 is the outer diameter D31 of the cylindrical body 31. The outer diameter of the suppressor 40 is the outer diameter D42 of the base 41 (lower base 42).
[0061] In this embodiment, as shown in the examples in Figures 1 to 3, the outer diameter of the pull-out electrode 10 is the smallest, followed by the insulating member 20 and the fixing member 30 in increasing order, with the suppressor 40 having the largest outer diameter. This shape (relationship of outer diameters) allows for efficient work when attaching and detaching the electron gun 1 from the device to which it is attached. Specifically, since the largest part, the suppressor 40, is on the opposite side from the pull-out electrode 10, the suppressor 40 is on the worker's side during work, improving workability.
[0062] The relationship between the outer diameters of the lead electrode 10, the insulating member 20, and the fixing member 30 may be as follows. In any case, the outer diameter of the suppressor 40 is larger than the outer diameters of the lead electrode 10, the insulating member 20, and the fixing member 30. However, for example, if the outside of the fixing member 30 is thicker, the outer diameter of the fixing member 30 may be larger than the outer diameter of the suppressor 40.
[0063] (1) Outer diameter of the extension electrode 10 > Outer diameter of the fixing member 30 > Outer diameter of the insulating member 20 In this case, for example, fixing the extension electrode 10 to the microscope and energizing it becomes easier. (2) Outer diameter of the fixing member 30 > Outer diameter of the extension electrode 10 > Outer diameter of the insulating member 20 In this case, for example, inserting and removing the electron gun 1 from a device such as a microscope becomes easier. (3) Outer diameter of the fixing member 30 > Outer diameter of the insulating member 20 > Outer diameter of the extension electrode 10 In this case, for example, parts used for the fixing member 30 can be managed separately from the extension electrode 10 and the insulating member 20 (they can be passed through the inside of the fixing member 30), making maintenance easier.
[0064] <Explanation of the assembly structure and procedure of emitter 2> Figure 10 is a cross-sectional view showing the assembly order of electron gun 1. The assembly procedure of electron gun 1 with the above configuration will be explained with reference to this figure. Assume that the insulating member 20 or the lead electrode 10 is attached to the electron beam device, for example.
[0065] As shown in Figure 10(a), a unit is prepared in which the lead electrode 10 is joined to the insulating member 20 with the fixing member 30 attached. If the outer diameter of the lead electrode 10 is larger than the upper opening 37 of the fixing member 30, the fixing member 30 should be passed through the insulating member 20 beforehand, and then the lead electrode 10 should be joined to the upper end surface 25. The fixing member 30 is moved to the vicinity of the upper end surface 25 of the insulating member 20 for the following operation.
[0066] Next, as shown in Figure 10(b), the suppressor 40 is inserted into the interior 28 of the insulating member 20 from the tip conical portion 46 side and moved upward. As a result, as shown in Figure 10(c), the lower end surface 26 of the convex portion 22 of the insulating member 20 comes into contact with the upper surface 43a of the upper base 43.
[0067] Finally, as shown in Figure 10(d), by moving the fixing member 30 downwards and then rotating it in the screw-tightening direction, the internal screw groove 38 of the fixing member 30 and the external screw groove 48 of the suppressor 40 engage, and the internal upper surface 34 of the fixing member 30 contacts and is fixed to the upper surface 23 of the protrusion 22. This allows the electron gun 1 to be properly attached to the electron beam device.
[0068] At this time, as shown in Figure 2, the condition of the suppressor 40 can be visually inspected through the notch 29. Since the tip cone portion 46 is provided with a tip window hole 49, the condition of the release member 99 attached to the suppressor 40, more specifically the condition of the tip 101, can be determined. If there are any problems with the mounting posture or position of the suppressor 40, or with the alignment or damage of the release member 99 (more specifically the tip 101), the suppressor 40 can be removed by loosening the fixing member 30 and releasing the fixation between the suppressor 40 and the insulating member 20 in the reverse order of the procedure shown in Figures 10(a) to 10(d). With the suppressor 40 removed, the through hole 47 provided on the side of the lower base 42 is exposed, and the release member 99 (base 103) inside can be easily removed by loosening the screw through the through hole 47. This makes it possible to efficiently replace the discharge member 99 alone or to perform precise positioning (centering) of the tip 101 under a microscope, while leaving the insulating member 20 and the lead electrode 10 on the device side (or having the entire unit removed and at hand).
[0069] In this way, by rotating the fixing member 30 itself, the fixing member 30 is moved vertically to fix the insulating member 20 and the suppressor 40. This eliminates the need for space required for fixing compared to a configuration where screws are provided separately to fix from the side. In other words, no working space is required on the outside of the electron gun 1 (emitter 2) in the lateral direction. Furthermore, since the fixing member 30 acts with a uniform force in the circumferential direction, it is possible to prevent misalignment or distortion that would occur when assembling the emitter 2 due to differences in the fixing force between the insulating member 20 and the suppressor 40 depending on the position. In other words, the alignment adjustment of the emitter 2 can be performed efficiently with high precision.
[0070] In summary, this embodiment is as follows: 1. An emitter 2 having: an emission member 99 that emits charged particles at its tip (tip 101); a base 41 (lower base 42, upper base 43) to which the emission member 99 is attached; and a voltage supply member that applies voltage to the emission member 99; and an insulating member 20 that has a cylindrical shape and houses the emission member 99 inside, with a lead electrode 10 joined to one end (upper end surface 25) and the other end (lower end surface 26) in contact with the base 41 of the suppressor 40, wherein the insulating member 20 is attached to the base 41 (mainly the upper base 43) by a removable fixing member 30. 2. The emitter 2 according to 1. wherein the insulating member 20 has a notch 29 or through hole that communicates the inside and outside within a range of 10 mm in the height direction from the joint portion with the lead electrode 10 (i.e., the upper end surface 25). 3. The emitter 2 according to 1. or 2. wherein the insulating member 20 has a protrusion 22 projecting outward at its lower part, the base 41 has a second surface (upper surface 43a) facing the first surface (lower end surface 26) below the protrusion 22, and the fixing member 30 is cylindrical and houses the base 41 (upper base 43) and the protrusion 22 inside, and presses the third surface (upper surface 23 of the protrusion 22), which is the upper surface of the protrusion 22, downward, thereby pressing the first surface (lower end surface 26) against the second surface (upper surface 43a). 4. The emitter 2 as described in 3. The fixing member 30 has a first screw groove (internal screw groove 38) on the inside, and the base 41 (upper base 43) has a second screw groove (external screw groove 48) on the outside that corresponds to the first screw groove (internal screw groove 38), and the first surface (lower end surface 26) is pressed against the second surface (upper surface 43a) when the first screw groove (internal screw groove 38) and the second screw groove (external screw groove 48) are screwed together. 5. An electron gun 1 having the emitter 2 as described in 1. or 2. and a drawout electrode 10 provided opposite to the emission member 99 of the emitter 2.
[0071] The embodiments of the present invention have been described above with reference to the drawings, but these are merely examples of the present invention, and various other configurations can be adopted. For example, the execution order of the steps performed in the embodiments is not limited to the order in which they are described. In the embodiments, the order of the steps can be changed to the extent that it does not impede the content. Furthermore, the embodiments and multiple modifications described above can be combined to the extent that they do not conflict in content.
[0072] This application claims priority based on Japanese Patent Application No. 2025-017380, filed on 5 February 2025, and incorporates all of its disclosures herein.
[0073] 1 Electron gun 2 Emitter 10 Lead-out electrode 11 Electrode body 12 Top surface 13 Bottom surface 14 Recess 15 Flat surface 16 Rib 17 Through hole 20 Insulating member 21 Cylindrical body 22 Protrusion 23 Top surface of protrusion 25 Upper end surface 26 Lower end surface 28 Interior 29 Notch 30 Fixing member 31 Cylindrical body 32 Top surface 33 Bottom surface 34 Interior top surface 36 Interior of cylinder 37 Upper opening 38 Inner screw groove 39 Through hole 40 Suppressor 41 Base 42 Lower base 43 Upper base 43a Top surface 44 Neck 45 Tip cylindrical part 46 Tip conical part 47 Through hole 48 Outer screw groove 48a Recess (divided groove) 49 Tip window 50 Bottom surface 51 Through hole 52 Housing section 52a First housing section 52b Second housing section 55 Upper end surface 59 Groove 64 First power supply 65 Second power supply 66 Third power supply 70 Fixing section 99 Discharge member 101 Chip 102 Filament 103 Base 104 First terminal 105 Second terminal
Claims
1. An emitter comprising: a discharge member that emits charged particles at its tip; a suppressor having a base to which the discharge member is attached and which applies a bias voltage to the discharge member; and an insulating member having a cylindrical shape that houses the discharge member, with a lead electrode joined to one end and the other end in contact with the base of the suppressor, wherein the insulating member is attached to the base by a removable fixing member.
2. The emitter according to claim 1, wherein the insulating member has a notch or through hole that communicates the inside and outside within a range of 10 mm in the height direction from the joint portion with the lead electrode.
3. The emitter according to claim 1 or 2, wherein the insulating member has a protrusion projecting outward at its lower end, the base has a second surface facing the first surface below the protrusion, and the fixing member is cylindrical and houses the base and the protrusion inside, and presses the first surface against the second surface by pushing the third surface, which is the upper surface of the protrusion, downward.
4. The emitter according to claim 3, wherein the fixing member has a first screw groove on its inner side, and the base has a second screw groove on its outer side corresponding to the first screw groove, and the first surface is pressed against the second surface by the screwing of the first screw groove and the second screw groove.
5. An electron gun comprising: an emitter according to claim 1 or 2; and an extraction electrode provided opposite to the emission member of the emitter.