Charged particle beam device and electron gun

Abstract

A charged particle wire device is characterized by comprising: a charged particle source (202) consisting of a single crystal needle (204), a filament (205) connected to the single crystal needle, and an insulator (207) for holding the filament; a plurality of non-evaporating getter materials (201); an extraction electrode (203); and a housing (209) arranged around the axis of the electron wire emitted from the charged particle source; wherein a heater (212) for heating the plurality of non-evaporating getter materials is disposed at the extraction electrode, the plurality of non-evaporating getter materials are arranged side by side in the housing, the housing is connected to the extraction electrode, and an elastic member (250) is disposed between the non-evaporating getter materials and the housing, the elastic member (250) being configured to push the non-evaporating getter materials. This charged particle beam device comprises: a charged particle source 202 composed of a single crystal needle 204, a filament 205 connected to the single crystal needle, and an insulator 207 that holds the filament; a plurality of non-evaporation getter materials 201; a lead-out electrode 203; and a housing 209 disposed so as to surround the axis of an electron beam emitted by the charged particle source, the charged particle beam device being characterized in that a heater 212 for heating the plurality of non-evaporation getter materials is disposed in the lead-out electrode, the plurality of non-evaporation getter materials in the housing are disposed side by side, the housing is connected to the lead-out electrode, and elastic members 250 configured to press the non-evaporation getter materials are disposed between the non-evaporation getter materials and the housing.

Description

[Technical Field]

[0001] This invention relates to a charged particle wire device. [Previous Technology]

[0002] A charged particle beam device is a device that uses charged particle beams, such as electron beams, to irradiate a sample and detects secondary electrons, penetrating electrons, reflected electrons, X-rays, etc., emitted from the sample, thereby generating an observation image of the sample. To obtain a high-resolution observation image, a high-brightness electron source (charged particle source) is required, such as a cold cathode field emission (CFE) electron source. A CFE electron source emits electron beams (charged particle beams) by concentrating an electric field at the tip of a sharpened single crystal (gun tip). If residual gas in the vacuum is adsorbed at the gun tip, the emitted current becomes unstable. Therefore, the pressure around the electron source (charged particle source) must be reduced (the vacuum level increased).

[0003] An electron source (charged particle source) is mounted on an electron gun (vacuum container) whose interior is set to a vacuum. As a method to reduce the pressure inside the vacuum container, a non-evaporable getter (NEG) material is used. Unlike conventional evaporative getters, NEG material does not evaporate even when heated (activated) in a vacuum and retains its original shape. If the NEG material is activated first and then cooled back to room temperature, it adsorbs and traps gases, thus providing a vacuum degassing effect. Patent Document 1 discloses an electron gun mirror column having a sheet with a NEG alloy film formed on it. Previous Art Documents Patent Documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2007-157682 [Summary of the Invention]

[0005] The problem that the invention is intended to solve

[0006] However, the method for fixing the NEG material in Patent Document 1 does not adequately consider this. The NEG material is a accumulative vacuum pump; if its surface is covered with gas, it will lose its exhaust velocity. Therefore, repeated activation is necessary to allow the adsorbed gas to diffuse into the material's interior and clean the surface, thus restoring the exhaust velocity. According to the research results of the inventive team, the thickness of the NEG material formed by film deposition is as thin as the micrometer scale, therefore the capacity for diffused adsorbed gas inside is small. After several activation cycles, it will reach its lifespan and become unable to recover its exhaust velocity. Therefore, it is impossible to maintain a stable current for the charged particle wire device for a long period.

[0007] Further research by the invention team revealed that NEG materials with a thickness exceeding millimeters have a large capacity to diffuse adsorbed gases into the interior, and their lifespan does not end even after dozens of activation cycles. By using bulk NEG materials, a stable current can be maintained for a long period of time.

[0008] Here, the problem to be solved in the case of using bulk NEG material is that the bulk NEG material must be fixed in direct contact with other parts. The coefficients of thermal expansion of the bulk NEG material differ from those of the other parts, thus stress is applied to the NEG material due to the difference in expansion during activation. As a result, the NEG material may crack and break, and fragments of the NEG material become foreign objects that scatter around. These foreign objects can cause discharge, leading to the destruction of the electron source.

[0009] Therefore, the present invention aims to provide a charged particle wire device, which arranges bulk NEG material around an electron source to stabilize the emitted current and reduce the damage of the NEG material, thereby maintaining a stable emitted current over a long period. Technical means to solve the problem

[0010] A charged particle beam device, characterized by comprising: a charged particle source, consisting of a single crystal needle, a filament connected to the single crystal needle, and an insulator holding the filament; a plurality of non-evaporating getter materials; a housing arranged around the axis of the electron beam emitted from the charged particle source; and an output electrode having the housing; a heater for heating the plurality of non-evaporating getter materials is disposed on the output electrode, the plurality of non-evaporating getter materials are arranged side by side within the housing, and an elastic member is disposed between the non-evaporating getter materials and the housing, the elastic member being configured to push the non-evaporating getter materials. Effects of the Invention

[0011] According to the present invention, a charged particle wire device can be provided that stabilizes the discharged current and maintains stability over a long period of time.

Implementation Method

[0013] Embodiments of the charged particle beam apparatus of the present invention will be described below with reference to the accompanying drawings. The charged particle beam apparatus is a device that irradiates a sample with charged particle beams such as electron beams, and detects secondary electrons, penetrating electrons, reflected electrons, X-rays, etc., emitted from the sample to generate an observation image of the sample. Embodiment 1

[0014] Figure 1 illustrates the overall structure of a scanning electron microscope using an example of a charged particle beam apparatus. The scanning electron microscope is an apparatus that uses electron beams 101 to irradiate a sample 102, detects secondary electrons or reflected electrons emitted from the sample 102, and obtains an image of the sample 102. It includes a microscope body 103 that maintains an internal vacuum and a sample chamber 104. The microscope body 103 is connected to ground potential. The interior of the microscope body 103 is divided from top to bottom into a first vacuum chamber 105, a second vacuum chamber 106, a third vacuum chamber 107, and a fourth vacuum chamber 108. An aperture is positioned at the center of the electrodes separating each vacuum chamber, allowing the electron beams 101 to pass through. Each vacuum chamber is subjected to differential venting. The pressure in the first vacuum chamber 105, second vacuum chamber 106, third vacuum chamber 107, and fourth vacuum chamber 108 is higher in the lower vacuum chambers (the ones closer to the sample chamber 104). The following describes the first vacuum chamber 105, the second vacuum chamber 106, the third vacuum chamber 107, the fourth vacuum chamber 108, and the sample chamber 104.

[0015] The first vacuum chamber 105 is the internal space of the lead-out electrode 203, and is evacuated by the NEG material 201 of the bulk material. The pressure in the first vacuum chamber 105 is lower than that in the other two vacuum chambers 106, 107, and 108, and is evacuated to an extremely high vacuum region of 1×10⁻⁹ Pa to 1×10⁻¹⁰ Pa or lower. A CFE electron source 202 is disposed in the first vacuum chamber 105, and the lead-out electrode 203 is arranged around it.

[0016] At the two pins of the CFE electron source 202, an accelerating power supply 114 is connected via a flushing power supply 110, and a negative accelerating voltage of -1kV to -100kV relative to the ground potential supplied from the accelerating power supply 114 is normally applied. A suppressor power supply 124 is connected to the suppressor of the CFE electron source 202, and a suppressor voltage of +1kV to -1kV relative to the accelerating voltage is applied. The lead-out electrode 203 has a cup-shaped shape, separating the first vacuum chamber 105 from the second vacuum chamber 106. A lead-out power supply 109 is connected to the lead-out electrode 203, and a positive lead-out voltage of up to +6kV relative to the accelerating voltage applied to the two pins of the CFE electron source 202 is applied. By applying the lead-out voltage to the lead-out electrode 203, an electron wire 101 is emitted from the CFE electron source 202.

[0017] During the rinsing of the CFE electron source 202, a negative accelerating voltage plus a voltage of several volts is applied to one of the two pins by the rinsing power supply 110, creating a potential difference of several volts between the two pins. A pulsed current is then applied to the filament, thereby heating it to 2000°C (rinsing). This rinsing operation removes residual gas adsorbed on the CFE electron source 202, thereby resetting the unstable time variation of the emission current. The first vacuum chamber 105 and the second vacuum chamber 106 are subjected to differential exhaust, resulting in a pressure difference of several digits. Details of the structure of the CFE electron source 202 and its surroundings will be described later using Figure 2.

[0018] The second vacuum chamber 106 is a space surrounded by the electron gun vacuum container 121 and the accelerating electrode 113 outside the extraction electrode 203, and is connected to the piping 120. An ion pump 111 and an auxiliary NEG pump 112 are located at the tip of the piping 120, and the second vacuum chamber 106 is evacuated. The pressure in the second vacuum chamber 106 is in the ultra-high vacuum region, ranging from 1×10⁻⁷ Pa to 1×10⁻⁹ Pa. The accelerating electrode 113 is disposed in the second vacuum chamber 106, which is isolated from the third vacuum chamber 107. The accelerating electrode 113 and the electron gun vacuum container 121 are connected to ground potential. The electron line 101 is accelerated to a predetermined speed according to the accelerating voltage. An electrostatic lens is formed in the space where the extraction electrode 203 and the accelerating electrode 113 face each other. The extraction electrode 203 and the accelerating electrode 113 have a Butler lens structure to reduce the aberrations of the electrostatic lens. The configuration above the accelerating electrode 113 is collectively referred to as the electron gun 122. A baking heater 130 is installed in the atmosphere outside the electron gun 122. While the electron gun 122 is evacuated by the ion pump 111 or the auxiliary NEG pump 112, the entire electron gun 122 is heated (baked) to 200°C by the baking heater 130, thereby making the second vacuum chamber 106 an ultra-high vacuum.

[0019] The third vacuum chamber 107 is vented by an ion pump 115. A condenser lens 116 is provided in the second vacuum chamber 107. The condenser lens 116 focuses the electron beams 101 to adjust the current, etc.

[0020] A detector 117 is provided in the fourth vacuum chamber 108. The detector 117 detects secondary electrons or reflected electrons emitted from the sample 102. Multiple detectors 117 can be provided, or they can be provided in the sample chamber 104 or other first vacuum chambers 105, second vacuum chambers 106, and third vacuum chambers 107.

[0021] The sample chamber 104 is evacuated by a turbomolecular pump 118. An objective lens 119 and a sample 102 are disposed in the sample chamber 104. Electron beams 101 are focused and irradiated onto the sample 102 by the objective lens 119.

[0022] Figure 2 illustrates an example of the configuration of the CFE electron source 202 and its surroundings. The CFE electron source 202 is composed of a gun tip 204, a filament 205, two pins 206, an insulator 207, and a suppressor 123. The gun tip 204 is a tungsten single crystal needle with a sharpened tip in the <310> or <111> orientation, and the radius of curvature of the tip is approximately 100 nm. The gun tip 204 is fused to the tip of the filament 205. The filament 205 is a tungsten polycrystalline wire shaped like a V-shaped hairpin. Pins 206 are fused to both ends of the filament 205. The two pins 206 are metal terminals and are electrically insulated from each other by being held by the insulator 207. The suppressor 123 is mounted on the outside of the insulator 207 by fitting, accommodating the insulator 207, the pins 206, the filament 205, and a portion of the gun tip 204. The suppressor 123 has an opening at the bottom, from which the tip of the gun tip 204 protrudes. The protrusion length is between 0.1 mm and 3 mm.

[0023] The holding part 208 is a metal cylinder that holds the entire CFE electron source 202 by fixing the suppressor 123. The holding part 208 is connected to the electron gun vacuum container 121 through the stop 252 and is electrically insulated from the pin 206. The gun tip 204 and the filament 205 are at the same potential as the pin 206 and are subjected to a negative accelerating voltage supplied from the accelerating power supply 114 during normal electron emission. The holding part 208 and the suppressor 123 are subjected to a suppressor voltage by the suppressor power supply 124. In addition, during rinsing, the filament 205 is heated by the rinsing power supply 110 and thus rinsed to remove residual gas adsorbed on the gun tip 204. Alternatively, the CFE electron source 202 may not have the suppressor 123, and electron beams can still be emitted even without it.

[0024] The lead-out electrode 203 comprises a metal lead-out electrode lower part 211, a lead-out electrode sidewall 210, an aperture 214, a housing 209, a coil spring 250, a load distribution plate 251, and NEG material 201. The parts other than the NEG material 201 are primarily made of materials such as stainless steel, titanium, and permalloy. The lead-out electrode lower part 211 is positioned closest to the tip of the gun tip 204, with a height distance of 0.3 mm to 10 mm between them. The housing 209 is connected to the lead-out electrode lower part 211. The NEG material 201 is disposed inside the housing 209. If a lead-out voltage is applied to the lead-out electrode 203, the constituent parts of the lead-out electrode 203 also become subject to the lead-out voltage and thus have the same potential. The lead-out electrode sidewall 210 is connected to the electron gun vacuum container 121 via an insulator 252, and the two are electrically insulated. A differential exhaust port 213 connecting the first vacuum chamber 105 and the second vacuum chamber 106 can also be provided on the side wall 210 of the lead electrode. The conductivity of the differential exhaust port 213 is made relatively small, creating a pressure difference of several digits between the first vacuum chamber 105 and the second vacuum chamber 106.

[0025] The heater 212 is disposed in the second vacuum chamber 106 and connected in contact with the side of the lead-out electrode sidewall 210. By heating the heater 212 to 400°C or higher, more preferably 500°C or higher, this heat is transferred through the lead-out electrode sidewall 210 to the housing 209, further activating the NEG material 201 inside. By connecting the heater 212 to the lead-out electrode 203, the heat conduction path to the housing 209 and the NEG material 201 of the lead-out electrode 203 can be shortened, thereby efficiently raising the temperature of the NEG material 201 and activating it. The heater 212 is a ceramic heater made of alumina, silicon nitride, boron nitride, aluminum nitride, etc. Ceramic heaters may constantly release gas, causing pressure deterioration. Therefore, the heater 212 is disposed on the second vacuum chamber 106 side to prevent pressure deterioration in the first vacuum chamber 105 and reduce the pressure in the first vacuum chamber 105.

[0026] The casing 209 is composed of a cover 253 and a container 254, which are fixed by bolts or screws (not shown). The casing 209 is arranged around an axis surrounding the tip 204 or the electron beam 101 emitted from the tip 204. NEG material 201 is stored inside the casing 209. The number of NEG materials 201 is increased as much as possible within the limited volume of the casing 209. The NEG materials 201 are arranged in a high-density circular pattern around the axis of the electron beam 101. The NEG materials 201 can also be arranged in two or more layers in the height direction. By arranging the NEG materials 201 in two or more layers in the height direction, the exhaust speed can be further improved. The NEG materials 201 can also be arranged in multiple rows in the radial direction. The casing 209 not only serves as a container for the NEG material 201 but also acts as a heat conduction path, uniformly transferring heat to the NEG material 201 during heating by the heater 212, thus activating it. The casing 209 has an opening 216 only on the first vacuum chamber 105 side, allowing the NEG material 201 to be used for vacuum venting, thereby making the first vacuum chamber 105 a very high vacuum. The casing 209 also acts as a partition separating the first vacuum chamber 105 from the second vacuum chamber 106. The first vacuum chamber 105 is vented via the NEG material 201, while the second vacuum chamber 106 is vented via the ion pump 111 or the auxiliary NEG pump 112, thus creating a differential venting structure between the first vacuum chamber 105 and the second vacuum chamber 106. The pressure in the first vacuum chamber 105 is lower than that in the second vacuum chamber 106. Even if the pressure in the second vacuum chamber 106 rises due to discharge or electron impact desorption, the pressure in the first vacuum chamber 105 remains low due to the effect of differential venting. As a result, the amount of gas adsorbed on the tip 204 is reduced, and the current in the electron wire 101 is attenuated or the noise is reduced, maintaining a stable electron wire.

[0027] The NEG material 201 is made of an alloy of zirconium, vanadium, and iron. The NEG material 201 is a bulk material individually formed with a thickness of 1 mm or more. The thickness of the NEG material 201 (1 mm or more) increases its internal capacity for gas diffusion and adsorption, thus extending its lifespan. The NEG material 201 is, for example, cylindrical, with a thickness, diameter, and height ranging from 1 mm to 100 mm. By using a bulk material with a thickness on the millimeter scale, the internal capacity for gas diffusion and adsorption is increased, allowing for activation cycles of dozens or more, providing sufficient lifespan for the practical use of charged particle wire devices. The more NEG materials 201 are disposed within the housing 209, the higher the exhaust speed and the lower the pressure in the first vacuum chamber 105. Since the NEG material allows gas to be adsorbed onto its surface for vacuum exhaust, increasing the area of ​​the NEG material 201 exposed in the first vacuum chamber 105 increases the exhaust speed. If a porous body made by sintering zirconium-vanadium-iron alloy powder is used in NEG material 201, micron-scale irregularities will appear on the surface, thus increasing the effective surface area and further improving the exhaust velocity. The shape of NEG material 201 is not limited to a cylinder; it can also be a block or a ring. Other materials can also be used for NEG material 201, and depending on the type of material, the activation temperature may be as low as 100°C. When the activation temperature is low, the NEG material 201 can be activated by heating the entire electron gun 122 with a baking heater 130 located on the outside of the electron gun 122. As a result, the heater 212 located in the second vacuum chamber 106 can be omitted.

[0028] As NEG material 201, a sheet with NEG material film can also be used. However, the thickness of the NEG material film is as thin as the micrometer scale, so the capacity for gas diffusion and adsorption inside is small, and the lifespan is reached after several activations. In addition, when using sheet NEG material 201, the sheet must be bent to increase the surface area of ​​the sheet installed in the housing in order to obtain sufficient exhaust velocity. However, the NEG material film will peel off from the bending point, generating a large amount of foreign matter, which is a problem to be solved. This foreign matter will cause discharge due to the voltage difference between the suppressor and the lead electrode, causing the tip 204 to break. In addition, the composition distribution of NEG film on sheet will vary due to film formation conditions, and the exhaust velocity of each sheet will be different. Therefore, the pressure of the first vacuum chamber 105 in each device will be different, causing differences in current stability, which is a problem to be solved. On the other hand, the individual NEG materials have small variations, allowing for control of the exhaust velocity by adjusting the number of units they can be arranged. Therefore, pressure variations within the first vacuum chamber 105 do not occur. As described above, by using individually formed block materials as the NEG material 201, sufficient lifespan and reduced foreign matter and material variations are achieved.

[0029] Next, the procedure for emitting the electron beam 101 will be described. If an extraction voltage is applied to the extraction electrode 203, a stronger electric field is applied to the tip of the gun tip 204, and the electron beam 101 is emitted by the electric field. If the suppressor voltage is changed, the electric field at the tip of the gun tip 204 will change, and the amount of emitted current can be adjusted. An aperture 214 is arranged in the center of the lower part 211 of the extraction electrode. The aperture of the aperture 214 is typically less than 1 mm, and more preferably less than 0.5 mm. The electron beam 101 passes through the aperture of the aperture 214 and advances toward the second vacuum chamber 106, expanding in a conical shape as it reaches the accelerating electrode 113. An aperture 215 is arranged in the center of the accelerating electrode 113. The outer periphery of the electron beam 101 is shielded by the aperture 215 or the accelerating electrode 113, and the central part advances toward the third vacuum chamber 107. This electron beam further advances downward and finally irradiates the sample 102.

[0030] Next, the function of the first vacuum chamber 105 in efficiently achieving an extremely high vacuum through vacuum exhaust will be explained. The ion pump 111 or the auxiliary NEG pump 112 suffers from low efficiency in exhaust velocity due to the conductivity of the exhaust path in the piping 120, resulting in low efficiency in exhausting the area around the electron source (charged particle source). On the other hand, the NEG material 201 is disposed very close to the electron source (charged particle source) inside the lead-in electrode 203, thus exhibiting high conductivity and a high efficient exhaust velocity. Therefore, it is possible to efficiently achieve vacuum exhaust around the electron source (charged particle source).

[0031] By pre-arranging a plurality of NEG materials 201 inside the housing 209 and mounting them onto the electron gun, assembly time is saved compared to mounting the NEG materials 201 onto the electron gun individually. Furthermore, the chance of foreign objects being generated due to the NEG materials 201 colliding with electron gun components during assembly is reduced. In addition, as a result of long-term use, when the NEG materials 201 reach the end of their lifespan, during maintenance of the charged particle beam device, all NEG materials 201 can be easily replaced with new ones simply by replacing the housing, thus restoring the exhaust speed.

[0032] The housing 209 is configured around an axis that runs along the direction of travel of the tip 204 or the electron wire 101. With this configuration, the distance between the NEG material 201 and the exhaust path of the tip 204 is shortened, increasing conductivity and effectively increasing exhaust velocity. By configuring the housing 209 at the same height as the tip 204, the distance can be minimized, maximizing conductivity. On the other hand, the housing 209 can also be configured at a different height from the tip 204. For example, when the height of the housing 209 is increased and a large number of NEG materials 201 are installed inside, due to space limitations, the housing 209 may be configured at a position higher than the tip 204. Even in this case, by configuring the housing 209 around an axis that runs along the electron wire 101, the distance from the tip 204 to the exhaust path of one of the NEG materials 201 can still be minimized, thereby improving conductivity.

[0033] The first vacuum chamber 105 is a small space confined to the interior of the lead-out electrode 203, accommodating a small number of components, thus resulting in a small total amount of gas released. Furthermore, the entire lead-out electrode 203 is heated to a high temperature by the heater 212, thereby removing molten hydrogen from the components and reducing the amount of gas released from each component. Combined with the increased effective exhaust velocity caused by the placement of the NEG material 201 within the lead-out electrode 203 and the reduced amount of degassed gas, the pressure in the first vacuum chamber 105 is efficiently reduced to an extremely high vacuum, providing a stable discharge current from the CFE electron source 202.

[0034] The arrangement and fixing method of the NEG material 201 will be explained using Figure 3. Figure 3 is a perspective view of a portion of the housing 209. In Figure 3, a cylindrical coordinate system is used, with the height direction represented by Z, the circumferential direction by θ, and the radial direction by R. The NEG material 201 is arranged inside the container 254 of the housing, covering the cover 253 of the housing from above. The NEG materials 201 are arranged regularly side-by-side in the circumferential direction (θ direction), and the NEG materials 201 can also be arranged in contact with each other. With this design, a plurality of NEG materials 201 can be arranged within the limited volume of the housing 209, thereby increasing the exhaust velocity and reducing the pressure in the first vacuum chamber 105. Two layers of NEG materials 201 are arranged in the height direction (Z direction) to increase the number arranged within the housing 209. Alternatively, the number of layers can be more than two. A load-distributing plate 251-A may also be disposed between the lower NEG material 201-A and the upper NEG material 201-B. A load-distributing plate 251-B and a coil spring 250-A are disposed between the upper NEG material 201-B and the cover 253. The coil springs 250-A are preferably disposed in multiples between the load-distributing plate 251-B and the cover 253. The container 254 has a partition wall 303, and the container 254 and the partition wall 303 are integrally formed. A load-distributing plate 251-C is disposed between the NEG materials 201-C and 201-D at the edges and the partition wall 303. A coil spring 250-B may also be disposed between the partition wall 303 and the load-distributing plate 251-C.

[0035] Load-distribution plate 251-A preferably contacts a plurality of NEG materials 201. The number of NEG materials in contact is at least two NEG materials with different positions in the circumferential direction and two NEG materials with different positions in the height direction, and at least three different NEG materials. Load-distribution plate 251-B also contacts a plurality of NEG materials, and at least two NEG materials with different positions in the circumferential direction. Load-distribution plate 251-C also contacts a plurality of NEG materials, and at least two NEG materials with different positions in the height direction.

[0036] The coil spring 250 is a spring made by winding a metal wire, and its material retains its elasticity even when heated during activation. The length of the coil spring 250 is extended and contracted from its natural length, and it presses against the parts in contact with it in the direction of extension and contraction to maintain the applied force.

[0037] If the cover 253 covers the container 254, the coil spring 250-A will be compressed by the cover 253, applying a force in the height direction to the load distribution plate 251-B. The load distribution plate 251-B distributes the force of the coil spring 250-A to the plurality of NEG materials 201-B that are in contact below. The NEG materials 201-B are fixed in position by being pushed. The plurality of NEG materials 201-B will further transmit the pushing force to the load distribution plate 251-A below. The load distribution plate 251-A will distribute the applied force to the plurality of NEG materials 201-A that are in contact below, pushing and fixing them. In this way, the entire NEG material 201 is fixed by the coil spring 250-A, reducing the positional variation of the NEG material 201, especially the positional variation in the height direction. By reducing the positional variation, damage to the NEG material 201 can be suppressed. The coil spring 250 is elastic and will return to its original length when the cover 253 is removed. Therefore, it can be reused as long as it retains its elasticity.

[0038] The coil spring 250-B, in its contracted state, applies a circumferential force to the load distribution plate 251-C. The load distribution plate 251-C distributes the force of the coil spring 250-B to the NEG materials 201-C and 201-D that it contacts, thus pressing and fixing them. The NEG materials 201-C and 201-D further transmit this force to other NEG materials that are in contact circumferentially, thus pressing the entire NEG 201 circumferentially. As a result, the entire NEG material 201 is fixed by the coil spring 250-B, reducing positional changes of the NEG material 201, especially in the circumferential direction. By configuring the coil spring to press and fix the NEG material 201 in height or circumferential direction as described above, it is possible to prevent the NEG material 201 from moving from its designated position and causing collisions or friction with other parts, i.e., sliding. Alternatively, the coil spring 250 can be added in the direction in which a force is applied in the radial direction. Even under these conditions, the NEG material 201 remains fixed, especially with reduced positional variation in the radial direction. Multiple coil springs 250 are configured to increase the pushing height, circumference, and radius, thereby further securing the NEG material 201. The dimensions of the NEG material 201, such as its height or diameter, may not be fixed, potentially leaving a gap between the cover 253 of the housing 209 and the NEG material 201-B, allowing the NEG material 201 to move. Therefore, by configuring coil springs 250 that push in the height direction, impacts or slippage caused by the movement of the NEG material 201 are prevented. Furthermore, if the direction of the cover 253 covering the housing 209 is circumferential, a gap is easily created in the circumferential direction, making it more suitable to configure coil springs 250 that push in the circumferential direction. If the direction of the cover 253 is radial, a gap is easily created in the radial direction, making it more suitable to configure coil springs 250 that push in the radial direction.

[0039] An exhaust path 306 is formed in the space adjacent to the coil spring 250 in the circumferential direction. The exhaust path 306 acts as a vacuum exhaust path with high conductivity, so that the surface of the NEG material 201 disposed on the outer side in the radial direction (the side with the larger R) participates in vacuum exhaust, thereby increasing the effective exhaust speed.

[0040] The load-distribution plate 251 is a metal plate with a certain width and length, which disperses stress by making surface contact with the NEG material 201. By using the load-distribution plate 251, the force of the coil spring 250 is uniformized, and the force is made evenly distributed by contact with multiple NEG materials 201, thus preventing stress concentration and breakage of the NEG material 201. The more the load-distribution plate 251 contacts the NEG material 201, the more uniform the stress is, and the breakage of the NEG material 201 caused by stress concentration can be suppressed. In addition, by using the load-distribution plate 251, even if the number of installed coil springs 250 is reduced, the entire NEG material 201 can still be fixed by applying force. Furthermore, by spherical or chamfering the end face of the load-distribution plate 251, the breakage of the NEG material 201 caused by sharp end face contact can be suppressed. A convex positioning portion 301 is provided on the load distribution plate 251, and a coil spring 250 is disposed thereon. By positioning the coil spring 250 in the designated positioning portion 301, the stress applied to the NEG material 201 is prevented from being unevenly distributed depending on the position. Alternatively, the positioning portion 301 can also be concave, or it can be combined with other parts.

[0041] Regarding other effects of the load distribution plate 251, compared to the case where multiple NEG materials 201 are stacked in contact, the surface area exposed in the first vacuum chamber 105 can be increased. The load distribution plate 251-A is narrower than the width of the NEG material 201 that is in contact with it, thereby exposing the upper surface 304 of the NEG material 201-A to the vacuum. As a result, the upper surface 304 participates in vacuum degassing. Similarly, the load distribution plate 251-B is also narrower than the width of the NEG material 201 that is in contact with it, thereby exposing the upper surface 305 of the NEG material 201-B to participate in vacuum degassing. In addition, a surface exposed to the vacuum is also left on the lower side of the NEG material 201-B. By distributing the load distribution plates between the NEG materials 201 in this way, exposing a portion of the upper or lower surface of the NEG materials 201 to the vacuum, the degassing speed of the NEG materials 201 can be increased. Alternatively, an opening 302 can be provided in the load distribution plate 251. By providing the opening 302, the surface of the NEG material 201 facing the opening 302 will be exposed to the vacuum and participate in vacuum degassing. As a result, the degassing speed can be increased.

[0042] If the NEG material 201 moves from its designated position, the exposed area in the vacuum will change, potentially reducing the exhaust speed. Furthermore, if the moved NEG material 201 collides or slides with other parts or other NEG materials 201, some parts may break, generating foreign matter. Especially when the NEG material 201 is a sintered body, its surface has micron-scale irregularities, making it prone to breakage and becoming foreign matter. Therefore, the NEG material 201 must be held in contact with other parts to prevent movement or sliding. As in this embodiment, the NEG material 201 is fixed by using a coil spring 250 to reduce impacts or sliding caused by movement. If stress is concentrated in a part of the NEG material 201, such as its corners, it may crack and break, generating a large amount of foreign matter. However, stress concentration can be prevented by using a load-distribution plate 251. Causes of movement of the NEG material 201 include vibrations during assembly or transport of the device, earthquakes, etc. On the other hand, even when the NEG material 201 is fixed, activation can cause abnormalities such as breakage of the NEG material 201 or gaps in the casing 209. Next, the function of using the coil spring 250 to prevent such abnormalities during activation will be explained.

[0043] Figure 4 illustrates the function of this configuration in preventing malfunctions during the activation of the NEG material 201. To enable the NEG material 201 to vent, activation must be performed by heating to above 400°C. Here, the thermal expansion rates of the NEG material 201, the load-dispersing plate 251, the container 254, and the cover 253 are different; therefore, malfunctions will occur due to changes in their lengths caused by expansion during heating. The coil spring 250 reduces these malfunctions during activation.

[0044] Figure 4(A) is a cross-sectional view of a portion of the housing 209 without the coil spring 250. In this configuration, as an example, three layers of NEG material 201 are arranged in the height direction, and the cover 253 and the uppermost NEG material 201 are in contact to fix the entire NEG material 201. If activation is performed in this configuration, the total length L1 of the NEG material 201 and the load distribution plate 251 may become longer than the height L2 of the inner side of the container 254 due to thermal expansion. At this time, the cover 253 will exert a downward force on the NEG material 201. If this force is concentrated at the corners of the NEG material 201, a crack 401 will occur, causing a portion of the NEG material 201 to break and fall off. In addition, a large amount of particulate foreign matter will be generated from the crack 401, which will damage the tip 204 through discharge. In addition, if L1 becomes longer than L2, the cover 253 will be pushed up, potentially creating a slight gap 402 in the housing 209. If gap 402 is created, the housing 209 will not function as a partition, and the first vacuum chamber 105 and the second vacuum chamber 106 will be connected through the gap 402. As a result, the pressure in the first vacuum chamber will increase (deteriorate). Furthermore, the differential venting effect of the first vacuum chamber 105 will disappear, so when the pressure in the second vacuum chamber 106 increases due to discharge or electron collision desorption, the pressure in the first vacuum chamber 105 will also increase, making it impossible to stabilize the current. Furthermore, if the height L2 of the container becomes longer than L1 due to thermal expansion, the NEG material 201 will become unable to be fixed by the cover 253, and collisions or sliding with other parts may occur due to the movement of the NEG material 201.

[0045] Figure 4(B) is a cross-sectional view of a portion of the housing 209 using the coil spring 250. In this configuration, two layers of NEG material 201 are arranged in the height direction, and the coil spring 250 and the load-distribution plate 251 are arranged between the cover 253 and the NEG material 201. If activated, the coil spring 250 will expand and contract, causing the height L3 to change, thereby preventing malfunctions caused by the thermal expansion of the components.

[0046] When L1 lengthens due to thermal expansion, the coil spring 250 compresses while maintaining the pushing force on the NEG material 201. At this time, since the coil spring 250 is an elastic body, the pushing force is sufficiently smaller than the force of the rigid body, i.e., the cover 253, shown in FIG. 4(A). Furthermore, the force of the coil spring 250 is distributed throughout the NEG material 201 by the load distribution plate 251. As a result, cracking 401 in the NEG material 201 is prevented. In addition, by compressing the coil spring 250 to prevent the cover 253 from changing position, the cover 209 will not have a gap 402. As a result, differential exhaust between the first vacuum chamber 105 and the second vacuum chamber 106 is maintained. Furthermore, even when the height L2 of the container lengthens due to thermal expansion, the NEG material 201 is still pushed and kept fixed by the extension of the coil spring 250. As a result, even during heating, it prevents impacts or slippage caused by movement of the NEG material 201. Furthermore, even after activation ends and the temperature returns to normal, the coil spring 250 restores its original length, and each component returns to its original position and shape, while the NEG material 201 remains in a pressed state and is fixed. In this way, by configuring the coil spring 250 to extend and retract its length, it absorbs positional changes caused by the thermal expansion of other components even during heating, thus preventing malfunctions.

[0047] Furthermore, although Figure 4 illustrates the effect of the coil spring 250 disposed in the height direction, the coil spring disposed in the circumferential direction also prevents the NEG material 201 from cracking 401 or gap 402 caused by thermal expansion in the circumferential direction, or the impact or sliding caused by the movement of the NEG material 201. In addition, the coil spring 250 can also be disposed in the radial direction (R direction), and even in this case, abnormalities caused by thermal expansion in the radial direction can still be prevented.

[0048] As described above, by using the coil spring 250 to fix the NEG material 201, the decrease in exhaust speed caused by the movement of the NEG material 201 can be reduced, as well as the generation of foreign matter due to collision or sliding with other parts or other NEG materials. Furthermore, by using the coil spring 250, the breakage of the NEG material 201 and the generation of foreign matter during the activation of the NEG material 201, as well as the generation of gap 402 in the housing 209, can be prevented. In addition, by using the NEG material 201 to efficiently exhaust the vacuum from the first vacuum chamber 105, an extremely high vacuum can be achieved. Furthermore, by differentially exhausting the first vacuum chamber 105, the extremely high vacuum state of the first vacuum chamber 105 can be maintained without being affected by the pressure of the second vacuum chamber 106. Furthermore, by using individually formed NEG materials with millimeter-scale thicknesses in the NEG material 201, a longer lifespan, reduction of foreign matter, and reduction of differences in exhaust speed can be achieved. Based on these results, a charged particle wire device with long-term current stabilization will be provided. Example 2

[0049] Example 1 describes a configuration for fixing the NEG material 201 using a coil spring 250. Example 2 will describe a configuration for fixing the material using a coil spring 250 when there is no container partition 303. Furthermore, since some of the configurations or functions described in Example 1 can be applied to Example 2, the same reference numerals are used for the same configurations and functions, and descriptions are omitted.

[0050] The method for fixing the NEG material 201 in this embodiment will be explained using FIG. 5. In this configuration, the container 254 does not have a partition 303, and the NEG materials 201 are continuously arranged in the circumferential direction. In order to fix the NEG materials 201 in the circumferential direction, a load-distribution plate 251-C and a load-distribution plate 251-D are arranged between the NEG material 201-C at one end and the NEG material 201-E at the other end facing each other. A coil spring 250-B is arranged between the load-distribution plate 251-C and the load-distribution plate 251-D. The coil spring 250-B is arranged in a state of contraction from its natural length and applies a force in the circumferential direction. This force is transmitted to the load-distribution plate 251-C, and then distributed to the NEG materials 201-C and NEG materials 201-D. Furthermore, this force is sequentially transmitted to the other adjacent NEG materials 201 in the circumferential direction. As a result, the entire NEG material 201 is pressed and fixed. The load-distributing plate 251-C disperses and transmits stress, thus preventing the NEG material 201 from cracking or the formation of foreign objects. The coil spring 250-B also applies force to the load-distributing plate 251-D in the opposite circumferential direction. This force is distributed and transmitted to NEG materials 201-E and 201-F, and then sequentially to other NEG materials 201 (not shown) in front of them. As a result, all NEG materials 201 are pressed and fixed. As in this embodiment, even without partition walls 303 in the circumferential direction of the container, the NEG materials 201 are fixed by arranging coil springs 250 and load-distributing plates 251 between adjacent NEG materials 201, reducing positional changes, especially in the circumferential direction. This prevents movement, impact, or sliding of the NEG materials 201. Furthermore, when the NEG material 201 is activated, the coil spring 250 will also absorb displacement due to thermal expansion, thereby preventing the formation of cracks 401 or foreign objects, and the formation of gaps 402 in the casing 209. Although in this embodiment the coil spring 250 is arranged between adjacent NEG materials 201 in the circumferential direction, the same effect can be achieved by arranging the coil spring 250 and the load distribution plate 251 between adjacent NEG materials 201 in the height or radial direction. Example 3

[0051] In Embodiment 2, a configuration was described in which a coil spring 250 was used for fixing when there was no container partition 303. In Embodiment 3, a configuration in which a leaf spring 601 was used instead of the coil spring 250 for fixing will be described. In addition, some of the configurations or functions described in Embodiments 1 and 2 can be applied to Embodiment 3, so the same reference numerals are used for the same configurations and functions and the description is omitted.

[0052] The fixing method of the NEG material 201 in this embodiment will be explained with reference to FIG. 6. The leaf spring 601 has a structure formed by folding a metal plate. The pleated metal plate has elasticity to extend and retract, and maintains the applied force by pressing against the contacting parts. The leaf spring 601 is made of metal, so that it retains its elasticity even when heated during activation.

[0053] A leaf spring 601-A is disposed between the NEG material 201 and the cover 253. When the cover 253 covers the container 254, the leaf spring 601-A is compressed by the cover 253, applying a force in the height direction. This force is distributed and transmitted to the plurality of NEG materials 201 in contact below, and further transmitted to the plurality of NEG materials 201 in the lower layer through the load distribution plate 251. As a result, all NEG materials 201 are pressed and fixed in this position, especially reducing the change in position in the height direction. The leaf spring 601 is elastic and returns to its original length when the cover 253 is removed. Therefore, it can be reused.

[0054] A leaf spring 601-B is disposed between the container partition 303 and the NEG material 201. The leaf spring 601-B is disposed in a contracted state and applies a force in the circumferential direction. This force is distributed and transmitted to the plurality of NEG materials 201 in contact, and further transmitted to the NEG materials 201 adjacent in the circumferential direction. As a result, all NEG materials 201 are pressed and fixed, and the positional variation of the NEG materials 201, especially the positional variation in the circumferential direction, is reduced.

[0055] The leaf spring 601 has a surface structure, thus enabling it to be pressed with uniform stress through surface contact. As a result, stress concentration on a portion of the NEG material 201 can be prevented, thus avoiding breakage or foreign matter. Furthermore, the leaf spring 601 can contact multiple NEG materials 201, thus itself having the effect of dispersing force like a load-dispersing plate. Therefore, the load-dispersing plate 251-B adjacent to the coil spring 250 described in Embodiment 1 can be omitted, thereby reducing the number of parts.

[0056] As in this embodiment, the leaf spring 601 can also be used to fix the NEG material 201, thereby preventing impact or sliding caused by the movement of the NEG material 201. Furthermore, when the NEG material 201 is activated, the leaf spring 601 will absorb displacement due to thermal expansion, thereby preventing the formation of cracks 401 or foreign objects, and preventing the formation of gaps 402 in the housing 209. Example 4

[0057] Embodiment 3 describes a configuration using a leaf spring 601 for fixing. Embodiment 4 will describe a configuration using a leaf spring 701 arranged in the radial direction for fixing. Furthermore, since some of the configurations or functions described in Embodiments 1 to 3 can be applied to Embodiment 4, the same reference numerals are used for the same configurations and functions, and descriptions are omitted.

[0058] The method for fixing the NEG material 201 in this embodiment will be explained using FIG. 7. In this configuration, two rows of NEG materials 201 are arranged in the radial direction to increase the number of NEG materials 201 installed in the housing 209 and improve the exhaust speed. The NEG materials 201-G in the first row and the NEG materials 201-H in the second row in the radial direction are in contact with each other, and the NEG materials 201 in the same row are also in contact with each other in the circumferential direction. As a result, a plurality of NEG materials 201 are installed in the housing 209, increasing the exhaust speed. The load distribution plate 251 is also widened in the radial direction so that it contacts the NEG materials 201 in both the first and second rows in the radial direction to distribute and transmit the force of the coil spring 250 to the two rows. The opening 302 of the load distribution plate 251 is also widened by spanning two rows of NEG material 201 to increase the surface area of ​​the NEG material 201 exposed in the first vacuum chamber 105.

[0059] A leaf spring 701 is disposed between the NEG material 201 and the side wall 702 of the container. The leaf spring 701 is constructed as the leaf spring 601 described in Embodiment 3, and is constructed by folding a metal plate to apply force by pressing against the contacting parts. It retains its elasticity even when heated during activation.

[0060] The leaf spring 701 is configured in the contracted state to apply a force in the radial direction. This force is distributed and transmitted to the NEG material 201-H in the second row of the radial direction that it contacts. Furthermore, this force is transmitted to the NEG material 201-G in the first row of the radial direction on the inner side. As a result, all NEG materials 201 are pressed and fixed, especially reducing positional changes in the radial direction. Alternatively, a load-dispersing plate can be added between the NEG material 201-G in the first row of the radial direction and the NEG material 201-H in the second row. In this case, the force pressing against the NEG material 201-H in the second row will be further dispersed and averaged by the added load-dispersing plate before being transmitted to the NEG material 201-G in the first row.

[0061] As in Embodiment 3, the leaf spring 701 has a surface structure, thus uniformizing stress through surface contact. As a result, stress concentration on a portion of the NEG material 201 is prevented from causing cracks or foreign objects.

[0062] As in this embodiment, the leaf spring 701 can also be used to fix the NEG material 201, thereby preventing impact or sliding caused by the movement of the NEG material 201. Furthermore, when the NEG material 201 is activated, the leaf spring 701 will absorb displacement due to thermal expansion, thereby preventing the formation of cracks 401 or foreign objects, and the formation of gaps 402 in the casing. Example 5

[0063] Embodiment 4 describes a configuration in which a leaf spring 701 is arranged in the radial direction for fixing. Embodiment 5 will describe a configuration in which a gap-filling spacer 801 is arranged in the radial direction for fixing. In addition, some of the configurations or functions described in Embodiments 1 to 4 can be applied to Embodiment 5, so the same reference numerals are used for the same configurations and functions and the description is omitted.

[0064] The method for fixing the NEG material 201 in this embodiment will be explained with reference to FIG. 8. In this configuration, the NEG material 201 is fixed by a metal elastic spacer 801. The spacer is preferably annealed to soften it and make it elastic. Stainless steel or permalloy, titanium or titanium alloy, aluminum alloy, or copper alloy are used for the spacer 801.

[0065] A spacer 801-A is disposed between the NEG material 201 and the cover 253. The spacer 801-A has a plate-like structure and a thickness. When the cover 253 covers the container 254, the spacer 801-A is pressed down by the cover 253 and slightly compressed, applying a force in the height direction. This force is distributed and transmitted to the plurality of NEG materials 201 in contact below, and further transmitted to the plurality of NEG materials 201 in the lower layer through the load-distribution plate 251. As a result, the entire NEG material 201 is pressed and fixed in this position, especially reducing the positional change in the height direction. The spacer 801 is elastic and will return to its original length when the cover 253 is removed. Therefore, it can be reused.

[0066] A spacer 801-B is disposed between the container partition 303 and the NEG material 201. The spacer 801-B has a block-shaped structure. The spacer 801-B is disposed by pressing into the container 254, applying a force in the circumferential direction. This force is distributed and transmitted to the plurality of NEG materials 201 in contact, and further transmitted to the NEG materials 201 adjacent in the circumferential direction. As a result, the NEG materials 201 are all pressed and fixed, and the positional variation of the NEG materials 201, especially the positional variation in the circumferential direction, is reduced.

[0067] The gap-filling spacer 801 has a surface structure, which allows for uniform stress distribution and compression by making it in surface contact with the NEG material 201. As a result, stress concentration on a portion of the NEG material 201 can be prevented from causing cracks or foreign objects. Furthermore, the gap-filling spacer 801 can contact multiple NEG materials 201, thus acting as a load-distribution plate. Therefore, the coil spring 250 and the adjacent load-distribution plates 251-B or 251-C described in Embodiment 1 can be omitted, thereby reducing the number of parts.

[0068] As in this embodiment, the NEG material 201 can also be fixed by using the gap filler 801, and the impact or sliding caused by the movement of the NEG material 201 can be prevented.

[0069] Several embodiments of the present invention have been described above. The present invention is not limited to the above embodiments, and the constituent elements can be modified and embodied without departing from the spirit of the invention. For example, the coil spring 250-A and load-distribution plate 251-B of Embodiment 1 can be combined with the leaf spring 601-B of Embodiment 3. Furthermore, as alternatives to the coil spring 250 or the leaf spring 601, a helical spring, a volute spring, a disc spring, a formed wire spring, a ring spring, etc., can also be used. Furthermore, as the gun tip 204, a low work function material such as CeB 6 or LaB 6, or a surface-inactive material such as a carbon-coated material, can be used instead of the tungsten single crystal. Furthermore, a nanowire electron source or a single-atom electron source can be used, which sharpens the radius of curvature of the tip to tens of nm or to the level of several atoms to one atom. Furthermore, the charged particle sources to which this invention is applicable are not limited to CFE electron sources, but can also be applied to Schottky electron sources or ion sources. For example, a gas electric field ionization ion source can be used as an ion source. A tungsten single crystal with a <111> crystal orientation is used at the tip 204, and a positive voltage is applied to the tip 204 relative to the extraction electrode 203. This allows an ion beam to be emitted from the tip 204 as a charged particle line, even if the rest of the device configuration is the same. In addition, an ultra-high vacuum of less than 1 × 10⁻⁷ Pa is required to obtain a stable discharge current from the Schottky electron source. By applying this invention, efficient vacuum venting around the electron source (charged particle source) can be achieved, thus balancing efficient vacuum venting with miniaturization of the charged particle line device. Furthermore, the impact of pressure rise in the second vacuum chamber is reduced, making it easier to maintain a stable discharge current. [Simplified Explanation of the Diagram]

[0012] [Fig. 1] A schematic cross-sectional view illustrating an example of the overall configuration of a scanning electron microscope, showing an example of a charged particle wire device. [Fig. 2] A schematic cross-sectional view illustrating an example of the configuration of the CFE electron source and its surroundings in Example 1. [Fig. 3] A schematic perspective view illustrating an example of the arrangement and fixing method of the NEG material in Example 1. [Fig. 4] A schematic cross-sectional view illustrating an example of the function of the coil spring in Example 1 to prevent abnormal activation of the NEG material. [Fig. 5] A schematic perspective view illustrating an example of the arrangement and fixing method of the NEG material in Example 2. [Fig. 6] A schematic perspective view illustrating an example of the arrangement and fixing method of the NEG material in Example 3. [Fig. 7] A schematic perspective view illustrating an example of the arrangement and fixing method of the NEG material in Example 4. [Fig. 8] A schematic perspective view illustrating an example of the arrangement and fixing method of the NEG material in Example 5.

Claims

1. A charged particle wire device, characterized by comprising: a charged particle source, consisting of a single crystal needle, a filament connected to the single crystal needle, and an insulator holding the filament; a plurality of non-evaporating getter materials; a housing arranged around the axis of the electron wire emitted from the charged particle source; and lead-out electrodes having the housing; wherein, The aforementioned lead-out electrode is configured to heat the aforementioned plurality of non-evaporative getter materials, the aforementioned plurality of non-evaporative getter materials are arranged side by side in the aforementioned housing, and an elastic member is disposed between the aforementioned non-evaporative getter materials and the aforementioned housing, the elastic member being configured to push the aforementioned non-evaporative getter materials.

2. The charged particle beam device as described in claim 1, wherein, The aforementioned elastic component is a coil spring or a leaf spring.

3. The charged particle beam device as described in claim 2, wherein, The aforementioned plurality of non-evaporative getter materials are individually formed bulk materials with a thickness of 1 mm or more.

4. The charged particle beam device as described in claim 3, wherein, A load-bearing dispersion plate that comes into contact with the aforementioned plurality of non-evaporative getter materials.

5. The charged particle beam device as described in claim 4, wherein, The aforementioned load-distribution plate has an opening.

6. The charged particle beam device as described in claim 3, wherein, The aforementioned elastic member is configured such that the aforementioned non-evaporative getter material is pushed in the height direction.

7. The charged particle beam device as described in claim 3, wherein, The aforementioned non-evaporative getter material is configured in two or more layers in the height direction.

8. The charged particle beam device as described in claim 3, wherein, A plurality of the aforementioned elastic members are arranged such that the aforementioned non-evaporative getter material is pushed from two or more opposite directions.

9. The charged particle beam device as described in claim 3, wherein, It comprises: a first vacuum chamber located inside the aforementioned lead-out electrode, wherein the aforementioned non-evaporative getter is disposed; a second vacuum chamber having a higher pressure than the aforementioned first vacuum chamber, wherein the aforementioned heater and the aforementioned lead-out electrode are disposed; and the aforementioned casing having an opening only on the side of the aforementioned first vacuum chamber.

10. A charged particle wire device, characterized by comprising: a charged particle source consisting of a single crystal needle, a filament connected to the single crystal needle, and an insulator holding the filament; a plurality of non-evaporating getter materials; a housing arranged around the axis of the electron wire emitted from the charged particle source; and lead-out electrodes having the housing; wherein, The aforementioned lead-out electrode configuration includes a heater that heats the aforementioned plurality of non-evaporative getter materials. The aforementioned plurality of non-evaporative getter materials are arranged side by side within the aforementioned housing. An elastic member is disposed between the aforementioned non-evaporative getter materials, and the elastic member is configured to push the aforementioned non-evaporative getter materials.

11. The charged particle beam device as described in claim 10, wherein, The aforementioned elastic component is a coil spring or a leaf spring.

12. The charged particle beam device as described in claim 11, wherein, The aforementioned plurality of non-evaporative getter materials are individually formed bulk materials with a thickness of 1 mm or more.

13. An electron gun, characterized by comprising: a charged particle source consisting of a single crystal needle, a filament connected to the single crystal needle, and an insulator holding the filament; a plurality of non-evaporating getter materials; a housing arranged around the axis of electron lines emitted from the charged particle source; and lead-out electrodes having the housing; wherein, The aforementioned lead-out electrode is configured to heat the aforementioned plurality of non-evaporative getter materials, the aforementioned plurality of non-evaporative getter materials are arranged side by side in the aforementioned housing, and an elastic member is disposed between the aforementioned non-evaporative getter materials and the aforementioned housing, the elastic member being configured to push the aforementioned non-evaporative getter materials.

14. The electron gun as described in claim 13, wherein, The aforementioned elastic component is a coil spring or a leaf spring.

15. The electron gun as described in claim 14, wherein, The aforementioned plurality of non-evaporative getter materials are individually formed bulk materials with a thickness of 1 mm or more.

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