Electron gun component, electron gun, and electron beam device

Abstract

An electron gun component comprising an electron emission member 10 that emits electrons, and a suppressor electrode 50 that has an opening 50a, wherein: the electron emission member 10 is inserted into the opening 50a; and at a minimum surface B among a cross section and an opening surface 50b of the opening 50a, the ratio ([(D+R1) / R2]×100) of the sum of a distance D between a center C1 of a region A occupied by the electron emission member and a center C2 of the minimum surface B and a radius R1 of the region A of the electron emission member to a radius R2 of the minimum surface B is 80.0% or less.

Description

Electron gun parts, electron guns, and electron beam devices

[0001] The present disclosure relates to electron gun components, electron guns, electron beam devices, and the like.

[0002] Electron guns are used in electron beam devices such as electron microscopes and semiconductor inspection devices. Electron guns include an electron gun component and an extraction electrode, and the electron gun component includes an electron-emitting member that emits electrons and a suppressor electrode having an opening. Various configurations of electron guns have been studied (see, for example, Patent Document 1 listed below).

[0003] Japanese Patent Application Laid-Open No. 2007-250491

[0004] In some electron gun components, an electron emitting member is inserted into an opening in a suppressor electrode. In this case, if the electron emitting member and the suppressor electrode are close to each other at the opening of the suppressor electrode, a discharge may occur between the electron emitting member and the suppressor electrode, preventing electron emission.

[0005] An object of one aspect of the present disclosure is to provide an electron gun component capable of suitably emitting electrons.An object of another aspect of the present disclosure is to provide an electron gun including such an electron gun component.An object of another aspect of the present disclosure is to provide an electron beam device including such an electron gun.

[0006] [1] An electron gun component comprising an electron-emitting member that emits electrons and a suppressor electrode having an opening, the electron-emitting member being inserted into the opening, wherein, at the smallest surface of the opening surface and cross section of the opening, the ratio ([(D+R1) / R2]×100) of the sum of the distance D between the center of an area occupied by the electron-emitting member and the center of the smallest surface and the radius R1 of the area of ​​the electron-emitting member to the radius R2 of the smallest surface is 80.0% or less. [2] The electron gun component according to [1], wherein the ratio ([D / R2]×100) of the distance D to the radius R2 is 30.0% or less. [3] The electron gun component according to [1] or [2], wherein the ratio ([R1 / R2]×100) of the radius R1 to the radius R2 is 50.0% or less. [4] The electron gun component according to any one of [1] to [3], wherein the distance D is 60 μm or less. [5] An electron gun component according to any one of [1] to [4], wherein the radius R1 is 125 μm or less and the radius R2 is 500 μm or less. [6] An electron gun comprising the electron gun component according to any one of [1] to [5] and an extraction electrode facing the suppressor electrode. [7] An electron beam device comprising the electron gun according to [6].

[0007] According to one aspect of the present disclosure, it is possible to provide an electron gun component capable of suitably emitting electrons. According to another aspect of the present disclosure, it is possible to provide an electron gun including such an electron gun component. According to another aspect of the present disclosure, it is possible to provide an electron beam device including such an electron gun.

[0008] Fig. 1 is a schematic end view showing an example of an electron gun component. Fig. 2 is a diagram showing an example of the aperture surface and the smallest surface of the cross section of an aperture in a suppressor electrode. Fig. 3 is a diagram showing another example of the aperture surface and the smallest surface of the cross section of an aperture in a suppressor electrode.

[0009] A numerical range "A or more" means A and a range exceeding A. A numerical range "A or less" means a range of A and less than A. In the numerical ranges described in stages in this specification, the upper limit or lower limit of a numerical range in a certain stage can be arbitrarily combined with the upper limit or lower limit of a numerical range in another stage. In the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with a value shown in the examples. "A or B" may include either A or B, or may include both. The materials exemplified in this specification may be used alone or in combination of two or more.

[0010] The electron gun component according to this embodiment includes an electron emitter that emits electrons and a suppressor electrode having an opening, the electron emitter being inserted into the opening of the suppressor electrode. In the electron gun component according to this embodiment, in the smallest surface of the opening surface and cross section of the suppressor electrode opening (hereinafter sometimes simply referred to as the "smallest surface B of the suppressor electrode"), the ratio X1 (X1 = [(D + R1) / R2] × 100) of the sum of the distance D between the center of an area A occupied by the electron emitter and the center of the smallest surface B of the suppressor electrode and the radius R1 of the area A to the radius R2 of the smallest surface B of the suppressor electrode is 80.0% or less.

[0011] According to the findings of the present inventors, in an electron gun component including an electron emitter inserted into an opening of a suppressor electrode, the electron emitter and the suppressor electrode may come close to each other at the opening of the suppressor electrode due to misalignment of the component during fabrication of the electron gun component, residual stress in the component, gravity applied to the component, and the like. In contrast, the ratio X1 in the electron gun component according to this embodiment can be used as an indicator of the degree of proximity between the electron emitter and the suppressor electrode at the opening of the suppressor electrode. According to the electron gun component according to this embodiment, the ratio X1 is 80.0% or less, thereby preventing the electron emitter and the suppressor electrode from coming close to each other at the opening of the suppressor electrode. Therefore, discharge between the electron emitter and the suppressor electrode is prevented, allowing electrons to be emitted favorably. The electron gun component according to this embodiment can be used as a Schottky electron gun component.

[0012] The electron gun component according to this embodiment includes an electron-emitting member that emits electrons. The electron-emitting member may emit electrons upon heating, upon application of an electric field, or upon both heating and application of an electric field. The electron-emitting member may have a tip that emits electrons. The electrons may be emitted in any direction, such as vertically upward, vertically downward, horizontally, inclined from the vertical, or inclined from the horizontal. The shape of the electron-emitting member is not particularly limited, and the electron-emitting member may be, for example, a columnar member extending in the electron emission direction. Examples of the cross-sectional shape of the electron-emitting member (a cross-section perpendicular to the electron emission direction) include a circle (e.g., a perfect circle, an ellipse), a polygon (e.g., a triangle, a rectangle, a pentagon, a hexagon), and the like. The tip of the electron-emitting member may be flat or sharp (e.g., tapered to a point). The length of the electron-emitting member (length in the electron-emitting direction) may be 100 to 5000 μm, 500 to 4000 μm, or 1000 to 3000 μm.

[0013] Examples of constituent elements of the electron-emitting member include tungsten, iridium, lanthanoids, etc. Examples of lanthanoids include lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Examples of constituent materials of the electron-emitting member include tungsten (for example, single crystals of tungsten such as W(100) and W(310)), lanthanoid-containing borides (LaB ６ (e.g., LaB ６ single crystal), CeB ６ (For example, CeB ６ Examples of the IrCe compound include Ir ２ Ce, Ir ３ Ce, Ir ７ Ce ２ , Ir ５ Ce, etc. The constituent materials of the electron-emitting member may be used singly or in combination of two or more.

[0014] The electron-emitting member is inserted into the opening (through-hole) of the suppressor electrode and penetrates the opening of the suppressor electrode, i.e., the electron-emitting member extends from one opening surface of the opening of the suppressor electrode to the other opening surface.

[0015] The electron gun component according to this embodiment includes a suppressor electrode having an opening (through-hole), through which an electron-emitting member is inserted. The suppressor electrode can be used to suppress electron emission from portions of the electron-emitting member other than the tip (for example, the side portions of the electron-emitting member), and can also be used to suppress electron emission from other members such as a filament, which will be described later. The shapes of the opening surface and cross section of the suppressor electrode include circles (perfect circles, ellipses, etc.) and polygons (triangles, rectangles, pentagons, hexagons, etc.).

[0016] The electron gun component according to this embodiment may include an electron source having an electron-emitting member and a suppressor electrode. The electron source may include a member other than the electron-emitting member. Examples of the member other than the electron-emitting member include a diffusion source (reservoir), a filament, a support member, and the like.

[0017] The diffusion source is in contact with the electron emitting member. The diffusion source may be disposed on the outer periphery of the electron emitting member between the tip and base ends of the electron emitting member, or on the outer periphery of the central part of the electron emitting member in the electron emission direction. The constituent material of the diffusion source is not particularly limited, and examples thereof include zirconium oxide (e.g., ZrO), calcium oxide (e.g., CaO), etc.

[0018] The filament is connected to the electron-emitting member and may be connected to the electron-emitting member via a conductive member between them. The filament can be used to heat the electron-emitting member. The electron source may have a single filament or multiple filaments. The filament may be made of a heat-resistant and conductive material. Elements constituting the filament include tungsten, rhenium, molybdenum, platinum, aluminum, silicon, potassium, etc. The filament may be a tungsten filament or a tungsten-rhenium (tungsten-rhenium alloy) filament.

[0019] The support member supports the filament. The support member may have an insulating member and a pair of terminals, the pair of terminals penetrating the insulating member at a distance from each other. In this case, one end of the filament may be connected to one terminal, and the other end of the filament may be connected to the other terminal.

[0020] The electron gun component according to this embodiment may include a first power supply for heating (heating by electrical current) the electron emitting member and / or the filament. The first power supply is capable of supplying a current to the electron emitting member for heating the electron emitting member, and is capable of supplying a current to the filament for heating the filament. The first power supply may be electrically connected to the electron emitting member via the filament, may be electrically connected to the electron emitting member via a terminal of the support member and the filament, or may be electrically connected to the filament via a terminal of the support member.

[0021] The electron gun component according to this embodiment may include a second power supply (bias power supply, suppressor power supply) for applying a voltage to the suppressor electrode. The second power supply may be connected to the suppressor electrode and may output a negative voltage with respect to the suppressor electrode.

[0022] 1 is a schematic end view of an example of an electron gun component 100. The electron gun component 100 includes an electron emitting member 10, a diffusion source (reservoir) 20, a filament 30, a support member 40, and a suppressor electrode 50.

[0023] The electron emitting member 10 is a columnar member extending in the electron emission direction and has a tip 10a that emits electrons. The diffusion source 20 is disposed on the outer periphery of the central portion of the electron emitting member 10 in the electron emission direction. The filament 30 has a shape obtained by bending a straight filament, and the base end of the electron emitting member 10 is connected to the bent portion of the filament.

[0024] The support member 40 has an insulating member (insulator) 42 and a pair of linear terminals 44. The pair of terminals 44 penetrate the insulating member 42 at a distance from each other. One end of the filament 30 is connected to one of the pair of terminals 44, and the other end of the filament 30 is connected to the other of the pair of terminals 44. A first power source (not shown) for heating the electron-emitting member 10 is electrically connected to the electron-emitting member 10 via the pair of terminals 44 and the filament 30.

[0025] The suppressor electrode 50 has a cylindrical portion 52, a connecting portion 54, a tapered portion 56, and a tip portion 58. The cylindrical portion 52 is a cylindrical body having an internal space and is connected to the insulating member 42 housed in the internal space via the connecting portion 54 disposed in the internal space. The tapered portion 56 is connected to the end of the cylindrical portion 52 in the electron emission direction. The tapered portion 56 has a diameter that decreases along the electron emission direction. The tip portion 58 is connected to the end of the tapered portion 56 in the electron emission direction. The tip portion 58 is flat, and an opening 50a through which the electron emitting member 10 is inserted is formed in the center of the tip portion 58. The opening 50a has an opening surface 50b on the tip 10a side of the electron emitting member 10 as the smallest surface B of the opening surface and cross section of the opening 50a. A second power supply (not shown) for applying a voltage to the suppressor electrode 50 is connected to the suppressor electrode 50.

[0026] In the electron gun component according to this embodiment, in the smallest surface B of the opening surface and cross section (cross section perpendicular to the opening direction) of the opening of the suppressor electrode, the ratio X1 (X1 = [(D + R1) / R2] × 100) of the sum of the distance D between the center of the region A occupied by the electron emitting member and the center of the smallest surface B of the suppressor electrode and the radius R1 of the region A of the electron emitting member to the radius R2 of the smallest surface B of the suppressor electrode is 80.0% or less, from the viewpoint of preventing the electron emitting member and the suppressor electrode from coming into close proximity to each other and thereby facilitating the suitable emission of electrons. The ratio X1 may be 75.0% or less, 70.0% or less, 65.0% or less, 60.0% or less, 55.0% or less, 50.0% or less, 45.0% or less, 40.0% or less, or 35.0% or less, from the viewpoint of preventing the electron emitting member and the suppressor electrode from coming into close proximity to each other and thereby facilitating the suitable emission of electrons. From the viewpoint of easily suppressing the emission of excess electrons that may cause noise, the ratio X1 may be 0% or more, more than 0%, 5.0% or more, 10.0% or more, 15.0% or more, 20.0% or more, 25.0% or more, 30.0% or more, 35.0% or more, 40.0% or more, 45.0% or more, 50.0% or more, or 55.0% or more. From these viewpoints, the ratio X1 may be 0% or more and 80.0% or less, 0% or more and 60.0% or less, 0% or more and 50.0% or more, 0% or more and 40.0% or more, 0% or more and 35.0% or more, more than 0% and 80.0% or less, more than 0% and 60.0% or less, more than 0% and 50.0% or less, more than 0% and 40.0% or less, more than 0% and 35.0% or less, 30.0 to 80.0%, 30.0 to 60.0%, 30.0 to 50.0%, 30.0 to 40.0%, or 30.0 to 35.0%. As shown in the examples described later, the ratio X1 can be calculated by obtaining the distance D, the radius R1, and the radius R2 using an observation image of the smallest surface B of the suppressor electrode. The observation image can be obtained by focusing on the smallest surface B of the suppressor electrode from the tip side of the electron emitting member in a direction perpendicular to the smallest surface B of the suppressor electrode. Regardless of the opening direction of the suppressor electrode, an image of the minimum plane B can be obtained. The minimum plane B is the plane with the smallest diameter, and when the opening plane or cross-sectional shape of the opening is not a perfect circle, it is the plane with the smallest radius of the largest inscribed circle.When the shape and dimensions of the opening are constant in the opening direction, the smallest surface B may be the opening surface (opening end) on the tip side of the electron emitting member in the opening.

[0027] The radius R1 of the region A occupied by the electron emitting member on the smallest surface B of the suppressor electrode may be in the following range. From the viewpoints of easily preventing the electron emitting member and the suppressor electrode from coming into close proximity, easily increasing brightness during electron emission, easily preventing positional change of the electron emitting member due to its own weight, and easily concentrating the electric field to emit electrons, the radius R1 may be 200 μm or less, 180 μm or less, 150 μm or less, 125 μm or less, 120 μm or less, 100 μm or less, 90.0 μm or less, 80.0 μm or less, 70.0 μm or less, or 65.0 μm or less. From the viewpoint of easily preventing damage due to impact, the radius R1 may be 1.0 μm or more, 5.0 μm or more, 10.0 μm or more, 20.0 μm or more, 30.0 μm or more, 40.0 μm or more, 50.0 μm or more, or 60.0 μm or more. From these viewpoints, the radius R1 may be 1.0 to 200 μm, 1.0 to 100 μm, 1.0 to 80 μm, 10.0 to 200 μm, 10.0 to 100 μm, 10.0 to 80.0 μm, 30.0 to 200 μm, 30.0 to 100 μm, or 30.0 to 80.0 μm. If the shape of region A is not a perfect circle, the radius R1 is the radius of the smallest circumscribing circle of region A (see FIG. 3 described below).

[0028] The radius R2 of the smallest surface B of the suppressor electrode may be in the following range, taking into consideration the ratio with R1 described below. From the viewpoint of easily suppressing the emission of excess electrons that may cause noise, the radius R2 may be 1000 μm or less, 900 μm or less, 800 μm or less, 700 μm or less, 600 μm or less, 500 μm or less, 400 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less. From the viewpoint of easily suppressing the electron emitting member and the suppressor electrode from coming into close proximity, the radius R2 may be 10 μm or more, 30 μm or more, 50 μm or more, 80 μm or more, 100 μm or more, 120 μm or more, 150 μm or more, 180 μm or more, or 200 μm or more. From these viewpoints, the radius R2 may be 10 to 1000 μm, 10 to 500 μm, 10 to 300 μm, 50 to 1000 μm, 50 to 500 μm, 50 to 300 μm, 100 to 1000 μm, 100 to 500 μm, or 100 to 300 μm. When the shape of the smallest surface B of the suppressor electrode is not a perfect circle, the radius R2 is the radius of the largest inscribed circle of the smallest surface B (see FIG. 3 described later).

[0029] A distance D between the center of an area A occupied by the electron emitting member on the smallest surface B of the suppressor electrode and the center of the smallest surface B of the suppressor electrode may be in the following range, taking into consideration the ratio with R1 described below. From the viewpoint of easily preventing the electron emitting member and the suppressor electrode from coming into close proximity, the distance D may be 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 20 μm or less, 15 μm or less, 10 μm or less, 5 μm or less, or 3 μm or less. From the viewpoint of improving the manufacturing yield, the distance D may be 0 μm or more, more than 0 μm, 1 μm or more, 3 μm or more, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. From these viewpoints, the distance D may be 0 μm or more and 500 μm or less, 0 μm or more and 80 μm or less, 0 μm or more and 30 μm or less, 0 μm or more and 15 μm or less, 0 μm or more and 10 μm or less, more than 0 μm and 500 μm or less, more than 0 μm and 80 μm or less, more than 0 μm and 30 μm or less, more than 0 μm and 15 μm or less, more than 0 μm and 10 μm or less, 1 to 500 μm, 1 to 80 μm, 1 to 30 μm, 1 to 15 μm, or 1 to 10 μm. The distance D can be adjusted by the relative position of the center of the region A with respect to the opening of the suppressor electrode. For example, the distance D can be adjusted by the installation positions of each member when fabricating the electron gun components (for example, the fixing position of the filament with respect to the terminal of the support member). The distance D can also be adjusted by passing current through the electron-emitting member, the filament, etc. to heat them.

[0030] The ratio X2 (X2 = [D / R1] × 100) of the distance D to the radius R1 may be in the following range. From the viewpoint of easily preventing the electron emitting member and the suppressor electrode from coming into close proximity and thereby facilitating favorable electron emission, the ratio X2 may be 100% or less, 90.0% or less, 80.0% or less, 70.0% or less, 60.0% or less, 50.0% or less, 40.0% or less, 30.0% or less, 20.0% or less, or 10.0% or less. From the viewpoint of improving the manufacturing yield, the ratio X2 may be 0% or more, more than 0%, 1.0% or more, 3.0% or more, 5.0% or more, 10.0% or more, 20.0% or more, 30.0% or more, 40.0% or more, 50.0% or more, 60.0% or more, or 70.0% or more. From these viewpoints, the ratio X2 may be 0% or more and 100%, 0% or more and 80.0%, 0% or more and 40.0%, 0% or more and 20.0%, 0% or more and 10.0%, more than 0% and 100% or less, more than 0% and 80.0% or less, more than 0% and 40.0% or less, more than 0% and 20.0% or less, more than 0% and 10.0% or less, 3.0 to 100%, 3.0 to 80.0%, 3.0 to 40.0%, 3.0 to 20.0%, or 3.0 to 10.0%.

[0031] The ratio X3 of the distance D to the radius R2 (X3 = [D / R2] × 100) may be in the following range. From the viewpoint of easily preventing the electron emitting member and the suppressor electrode from coming into close proximity and thereby facilitating favorable electron emission, the ratio X3 may be 50.0% or less, 40.0% or less, 30.0% or less, 25.0% or less, 20.0% or less, 15.0% or less, 10.0% or less, 8.0% or less, 6.0% or less, 5.0% or less, 3.0% or less, or 2.0% or less. From the viewpoint of improving the manufacturing yield, the ratio X3 may be 0% or more, more than 0%, 1.0% or more, 2.0% or more, 3.0% or more, 5.0% or more, 6.0% or more, 8.0% or more, 10.0% or more, 15.0% or more, 20.0% or more, or 25.0% or more. From these viewpoints, the ratio X3 may be 0% or more and 50.0% or less, 0% or more and 30.0% or less, 0% or more and 15.0% or less, 0% or more and 8.0% or less, 0% or more and 5.0% or less, more than 0% and 50.0% or less, more than 0% and 30.0% or less, more than 0% and 15.0% or less, more than 0% and 8.0% or less, more than 0% and 5.0% or less, 1.0 to 50.0%, 1.0 to 30.0%, 1.0 to 15.0%, 1.0 to 8.0%, or 1.0 to 5.0%.

[0032] The ratio X4 of the radius R1 to the radius R2 (X4 = [R1 / R2] × 100) may be in the following range. From the viewpoint of easily preventing the electron emitting member and the suppressor electrode from coming into close proximity to each other and thereby facilitating favorable electron emission, or from the viewpoint of easily concentrating an electric field and facilitating electron emission, the ratio X4 may be 80.0% or less, 70.0% or less, 60.0% or less, 50.0% or less, 40.0% or less, or 35.0% or less. From the viewpoint of easily preventing damage due to impact, the ratio X4 may be more than 0%, 1.0% or more, 5.0% or more, 10.0% or more, 15.0% or more, 20.0% or more, 25.0% or more, or 30.0% or more. From these viewpoints, the ratio X4 may be greater than 0% and less than 80.0%, greater than 0% and less than 60.0%, greater than 0% and less than 40.0%, 10.0 to 80.0%, 10.0 to 60.0%, 10.0 to 40.0%, 20.0 to 80.0%, 20.0 to 60.0%, or 20.0 to 40.0%.

[0033] Fig. 2 is a diagram showing an example of the opening surface and the smallest surface of the cross section of the opening of the suppressor electrode. In Fig. 2, area A occupied by the electron emitting member exists on smallest surface B of the suppressor electrode, and the shapes of area A and smallest surface B are perfect circles. Area A has a center C1 and a radius R1. Smallest surface B has a center C2 and a radius R2. Centers C1 and C2 are separated by a distance D.

[0034] Fig. 3 is a diagram showing another example of the aperture surface and the smallest surface of the cross section of the aperture of the suppressor electrode. Fig. 3 differs from Fig. 2 in that the shapes of region A and smallest surface B are polygonal rather than circular. When region A and smallest surface B are polygonal in this way, as shown in Fig. 3, the center C1 and radius R1 of region A are determined by the center and radius of the smallest circumscribing circle A' of region A, and the center C2 and radius R2 of smallest surface B are determined by the center and radius of the largest inscribing circle B' of smallest surface B.

[0035] 2 and 3 is expressed as the ratio of the sum of distance D and radius R1 to radius R2 ([(D+R1) / R2]×100). In this case, the greater the sum of distance D and radius R1, due to the greater distance D and / or radius R1, the more likely a discharge will occur because region A1 will be closer to the inner edge of the suppressor electrode located on the outer periphery of minimum face B. In other words, when the electron emitting member is positioned away from the center of minimum face B and / or when the dimension of the electron emitting member in the radial direction of minimum face B is large, the electron emitting member will be closer to the suppressor electrode, making it more likely a discharge will occur.

[0036] The electron gun according to this embodiment includes the electron gun component according to this embodiment and an extraction electrode facing the suppressor electrode. The electron gun according to this embodiment can be used as a Schottky electron gun.

[0037] The extraction electrode can be used to apply an electric field for emitting electrons from the electron-emitting member. The extraction electrode may have an opening (through-hole) through which the electrons emitted from the electron-emitting member pass. The extraction electrode may have a positive potential relative to the suppressor power supply having a negative potential.

[0038] The electron gun according to this embodiment may include a third power supply for applying a voltage to the extraction electrode. The third power supply may be connected to the extraction electrode and may output a positive voltage with respect to the extraction electrode.

[0039] The electron gun according to this embodiment may include an acceleration electrode facing the extraction electrode at a position opposite the suppressor electrode with respect to the extraction electrode. That is, the extraction electrode is disposed between the suppressor electrode and the acceleration electrode. The acceleration electrode can be used to accelerate electrons emitted from the electron-emitting member. The acceleration electrode may have an opening (through-hole) through which the electrons emitted from the electron-emitting member pass. The acceleration electrode may have a positive potential relative to the suppressor power supply having a negative potential.

[0040] The electron gun component according to the present embodiment may include a fourth power supply for applying a voltage to the acceleration electrode. The fourth power supply may be connected to the acceleration electrode and may output a positive voltage with respect to the acceleration electrode.

[0041] The electron beam apparatus according to this embodiment includes the electron gun according to this embodiment. Examples of the electron beam apparatus include an X-ray generator, an electron microscope, a semiconductor manufacturing apparatus, an analytical apparatus (an inspection apparatus such as an electron probe microanalyzer), and a processing apparatus (such as an electron beam evaporation apparatus).

[0042] The present disclosure will be described in more detail below using examples, but the present disclosure is not limited to the following examples.

[0043] <Production of Electron Gun Component> The electron gun component 100 shown in Fig. 1 was obtained by the following procedure: The electron gun component 100 was adjusted so that the electron emission direction was directed vertically upward.

[0044] First, a straight filament (material: tungsten, cross-sectional shape: circular, diameter: 127 μm) was bent to obtain the filament 30. Next, a support member 40 was prepared, which included an insulating member 42 (material: alumina) and a pair of terminals 44 (material: Kovar, distance between terminals: 5.59 mm). Next, one end of the filament 30 was welded and connected to one of the pair of terminals 44, and the other end of the filament 30 was welded and connected to the other of the pair of terminals 44.

[0045] A cylinder of tungsten single crystal (longitudinal direction of the cylinder: (100) crystal orientation of the tungsten single crystal, radius: 63.5 μm, length: 2000 μm) was prepared as the electron-emitting member 10. Next, the side of the base end of the electron-emitting member 10 was welded to the side of the bent portion of the filament 30. Subsequently, to release stress, the electron-emitting member 10 and the filament 30 were heated by passing electricity between a pair of terminals 44 of the support member 40.

[0046] The tip 10a of the electron-emitting member 10 was sharpened by electrolytic polishing. Next, a diffusion source (reservoir) 20 of zirconium oxide (ZrO) was formed on the outer periphery of the central part of the electron-emitting member 10 in the electron emission direction.

[0047] A suppressor electrode 50 having a cylindrical portion 52, a connecting portion 54, a tapered portion 56, and a tip portion 58 was prepared. Next, the electron emitting member 10 was inserted into the opening 50a of the suppressor electrode 50, and the support member 40 and the suppressor electrode 50 were connected via the connecting portion 54. The length of the portion of the electron emitting member 10 protruding from the opening surface 50b was 250 μm. As a result, an electron gun component 100 was obtained in which the relative relationship between the electron emitting member 10 and the opening 50a of the suppressor electrode 50 satisfied the relative relationship shown in Table 1. The relative relationship between the electron emitting member 10 and the opening 50a of the suppressor electrode 50 was adjusted by adjusting the installation positions of each component when fabricating the electron gun component 100 (e.g., the fixing position of the filament 30 relative to the terminal 44 of the support member 40), and by applying electricity to heat the electron emitting member 10, the filament 30, etc.

[0048] <Observation of Suppressor Electrode Opening> Using a scanning electron microscope (SEM), an image was obtained by focusing from the tip 10a side of the electron emitting member 10 onto the opening surface 50b of the suppressor electrode 50 in a direction perpendicular to the opening surface 50b. The image analysis procedure will be explained with reference to FIG. 3 . Image analysis software was used to identify the area A occupied by the electron emitting member on the minimum surface B of the suppressor electrode, and the minimum surface B of the suppressor electrode. The center and radius of the smallest circumscribing circle of area A were obtained as the center C1 and radius R1 of area A. The center and radius of the largest inscribing circle of minimum surface B were obtained as the center C2 and radius R2 of minimum surface B.

[0049] The radius R1 was 63.5 μm, and the radius R2 was 200 μm. The results of measuring the distance D between the center C1 of region A and the center C2 of the smallest surface B are shown in Table 1. Table 1 also shows the calculation results of the ratio X1 (X1 = [(D + R1) / R2] × 100) of the sum of the distance D and the radius R1 to the radius R2, the ratio X2 (X2 = [D / R1] × 100) of the distance D to the radius R1, and the ratio X3 (X3 = [D / R2] × 100) of the distance D to the radius R2. The ratio X4 (X4 = [R1 / R2] × 100) of the radius R1 to the radius R2 was 31.8%.

[0050] <Evaluation: Electron Emission Test> A Schottky electron gun was fabricated by connecting an extraction electrode, an acceleration electrode, and various power supplies (the first to fourth power supplies described above) to the above-described electron gun component 100. Electron emission was performed for 120 hours using this Schottky electron gun under the following conditions. Cases where electron emission could be continued for 120 hours were judged as "A," and cases where electron emission could not be continued for 120 hours due to discharge or the like were judged as "B." The results are shown in Table 1. Vacuum degree: 2.53 x 10 －８ Pa Temperature of electron-emitting member: 1800 K Bias voltage (voltage between electron-emitting member and suppressor electrode): -300 V Voltage of extraction power supply: 4700 V Diameter of extraction electrode opening: 0.5 mm Distance between tip of electron-emitting member and opening of extraction electrode: 0.75 mm Voltage of acceleration power supply: 4700 V Diameter of acceleration electrode opening: 2.0 mm Distance between extraction electrode and acceleration electrode: 10 mm

[0051]

[0052] 10...electron emitting member, 10a...tip, 20...diffusion source, 30...filament, 40...support member, 42...insulating member, 44...terminal, 50...suppressor electrode, 50a...opening, 50b...opening surface, 52...cylindrical portion, 54...connecting portion, 56...tapered portion, 58...tip portion, 100...electron gun component, A...area, A'...circumscribed circle, B...minimum surface, B'...inscribed circle, C1, C2...center, D...distance, R1, R2...radius.

Claims

1. An electron gun component comprising an electron-emitting member that emits electrons and a suppressor electrode having an opening, wherein the electron-emitting member is inserted into the opening, and the ratio ([(D+R1) / R2] x 100) of the sum of the distance D between the center of the area occupied by the electron-emitting member and the center of the smallest surface of the opening surface and cross section of the opening and the radius R1 of the area of ​​the electron-emitting member to the radius R2 of the smallest surface is 80.0% or less.

2. An electron gun component according to claim 1, wherein the ratio of the distance D to the radius R2 ([D / R2] x 100) is 30.0% or less.

3. An electron gun component according to claim 1, wherein the ratio of the radius R1 to the radius R2 ([R1 / R2] x 100) is 50.0% or less.

4. The electron gun component according to claim 1, wherein the distance D is 60 μm or less.

5. An electron gun component according to claim 1, wherein said radius R1 is 125 μm or less and said radius R2 is 500 μm or less.

6. An electron gun comprising the electron gun component according to any one of claims 1 to 5 and an extraction electrode facing the suppressor electrode.

7. An electron beam device comprising the electron gun according to claim 6.

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