JP7105022B1 - ELECTRON GUN, ELECTRON BEAM APPARATUS, AND METHOD FOR FORMING MULTI ELECTRON BEAMS - Google Patents

Abstract

An electron gun capable of forming more electron beams than the number of lenses provided in a multi-lens array, an electron beam application apparatus, and a method for forming multi-electron beams are provided. The electron gun includes an electron source, an anode for extracting electrons by an electric field formed by forming an electric field between the electron source, an anode for forming an electron beam, a multi-lens array, and a controller. When the electron beam irradiated to the multi-lens array is defined as the first electron beam, m first electron beams (m is an arbitrary integer equal to or greater than 2) are formed, and n multi-lens arrays (n is an arbitrary integer equal to or greater than 2) are formed. (any integer above), and a maximum of m×n second electron beams emitted from the multi-lens array can be formed, and the controller determines the emission positions of the m first electron beams when they are emitted. When one electron beam emission position is defined, the positional relationship between the first electron beam emission position and the lenses provided in the multi-lens array is controlled so as to achieve a preset positional relationship. [Selection drawing] Fig. 12

Description

The disclosure in this application relates to an electron gun, an electron beam application apparatus and a method of forming multiple electron beams.

Devices for generating multiple electron beams (multi-electron beams) are known.

As a related technique, Patent Literature 1 describes forming a plurality of electron beams from one electron beam emitted from an electron gun by using a correction electron optical system. Japanese Patent Application Laid-Open No. 2002-200003 describes an array-shaped correction electron optical system in which a plurality of holes through which electron beams pass is formed. Each hole is formed with a blanking electrode having a deflection function, an aperture diaphragm having an aperture (AP) that defines the shape of a penetrating electron beam, wiring, a unipotential lens, and a blanking aperture.

JP-A-9-245708

The invention described in Patent Document 1 can form a plurality of electron beams from one electron beam by passing the electron beam through an array-shaped correction electron optical system. Therefore, the more holes the arrayed correction electron optical system has, the more electron beams can be formed from one electron beam. However, the array-shaped correction electron optical system described in Patent Document 1 requires microfabrication to form electrodes and the like in each hole. Therefore, as the number of holes is increased, even one hole having a defect causes one array (hereinafter, a hole having a lens function through which an electron beam passes is referred to as a "lens", and two or more "lenses" are referred to as a "lens". The formed array is sometimes referred to as a "multi-lens array".) becomes a defective product, and there is a problem that the production yield of the multi-lens array deteriorates. In addition, as the number of lenses increases, the multi-lens array must be replaced if even one of the lenses becomes defective during use, resulting in increased running costs when using electron beams.

The present application was made in order to solve the above problems. (any integer of ) can form a maximum of m×n second electron beams by irradiating a multilens array having lenses.

An object of the present application is to provide an electron gun, an electron beam application apparatus, and a method for forming multiple electron beams, which can form more electron beams than the number of lenses provided in a multi-lens array.

The disclosure in this application relates to an electron gun, an electron beam application apparatus, and a method of forming multiple electron beams, which are described below.

上記（８）に記載の電子銃。
（１０）上記（９）に記載の電子銃を含む電子線適用装置であって、
前記電子線適用装置が、
走査電子顕微鏡、
電子線検査装置、または、
走査型透過電子顕微鏡、
である、
電子線適用装置。
（１１）マルチ電子ビームの形成方法であって、該形成方法は、
第１電子ビーム形成工程と、
第２電子ビーム形成工程と、
を含み、
前記第１電子ビーム形成工程は、
放出可能な電子を生成する電子発生源およびアノードとの間で電界を形成することで、電子発生源からｍ個（ｍは２以上の任意の整数）の第１電子ビームを射出し、
または、
放出可能な電子を生成する電子発生源およびアノードとの間で電界を形成することで電子ビームを引き出し、引き出した電子ビームを分割することでｍ個（ｍは２以上の任意の整数）の第１電子ビームを形成し、
前記第２電子ビーム形成工程は、
前記ｍ個の第１電子ビームを、ｎ個（ｎは２以上の任意の整数）のレンズを具備したマルチレンズアレイに照射し、前記マルチレンズアレイが具備する個々のレンズには異なる位置から照射された前記第１電子ビームが入射することで、最大ｍ×ｎ個の第２電子ビームを形成し、
前記電子発生源から前記マルチレンズアレイの方向をＺ方向と規定し、前記電子発生源から前記第１電子ビームが射出する際の射出位置を第１電子ビーム射出位置と規定した時に、
前記Ｚ方向に見た時の前記第１電子ビーム射出位置および前記マルチレンズアレイが具備するレンズの位置関係が、予め設定した位置関係となるように制御される、
マルチ電子ビームの形成方法。
（１２）前記第１電子ビーム射出位置の配置を射出配置と規定し、前記マルチレンズアレイが具備するレンズの配置をレンズ配置と規定した時に、
前記射出配置および前記レンズ配置は、同一または相似した配置であり、
前記Ｚ方向に見た前記射出配置を基準とした時に、前記Ｚ方向に見た前記レンズ配置が、前記射出配置と同一または相似した配置とならないように、前記射出配置の中心を回転軸として回転した位置に配置される、
上記（１１）に記載のマルチ電子ビームの形成方法。
（１３）像面に形成される前記第２電子ビームの照射領域を第２電子ビーム照射領域と規定した時に、
前記第２電子ビーム照射領域は、照射対象を欠損および重複なく埋め尽くすことができる形状である、
上記（１２）に記載のマルチ電子ビームの形成方法。
（１４）前記射出配置および前記レンズ配置が、正方形の４隅と中心、または、正六角形の６隅と中心であり、
前記射出配置および前記レンズ配置が以下の式を満たし、
前記Ｚ方向に見た前記射出配置を基準とした時に、前記Ｚ方向に見た前記レンズ配置を前記射出配置と同一または相似した配置から前記射出配置の中心を回転軸として回転した角度が、以下の式においてθで表される、

上記（１３）に記載のマルチ電子ビームの形成方法。
（１５）上記（１４）に記載のマルチ電子ビームの形成方法により形成されたマルチ電子ビームを照射対象上で走査する走査工程を含む、
マルチ電子ビームの走査方法。 (1) an electron source that generates electrons that can be emitted;
an anode capable of forming an electric field with the electron source, extracting the emissible electrons by the formed electric field, and forming an electron beam;
a multi-lens array;
a control unit;
an electron gun comprising
When the electron beam irradiated to the multi-lens array is defined as a first electron beam, m (m is an arbitrary integer equal to or greater than 2) first electron beams are formed,
The multi-lens array comprises n lenses (n is any integer equal to or greater than 2),
When the electron beam emitted from the multi-lens array is defined as the second electron beam,
The first electron beams irradiated from different positions are incident on the individual lenses of the multi-lens array, thereby forming a maximum of m×n second electron beams,
The control unit
When the direction from the electron source to the multi-lens array is defined as the Z direction, and the emission position when the m first electron beams are emitted is defined as the first electron beam emission position,
The positional relationship between the first electron beam emission position and the lenses included in the multi-lens array when viewed in the Z direction can be controlled so as to be a preset positional relationship.
electron gun.
(2) the electron source is a photocathode;
wherein the control unit controls the position of the excitation light received by the photocathode;
The electron gun according to (1) above.
(3) the electron source is a field emitter or Schottky;
the controller controls an element that emits the first electron beam from the field emitter or Schottky;
The electron gun according to (1) above.
(4) further comprising a rotation mechanism that rotates the multi-lens array with the Z direction as a rotation axis;
wherein the control unit controls the rotation mechanism;
The electron gun according to any one of (1) to (3) above.
(5) further comprising a moving mechanism for moving the multi-lens array in the Z direction as a moving direction;
The control unit controls the movement mechanism,
The electron gun according to any one of (1) to (4) above.
(6) When the arrangement of the first electron beam emission positions is defined as the emission arrangement and the arrangement of the lenses provided in the multi-lens array is defined as the lens arrangement,
the injection arrangement and the lens arrangement are the same or similar arrangements;
When the injection arrangement seen in the Z direction is used as a reference, the lens arrangement seen in the Z direction is rotated about the center of the injection arrangement as a rotation axis so that the arrangement is not the same as or similar to the injection arrangement. placed in the
The electron gun according to any one of (1) to (5) above.
(7) the injection arrangement and the lens arrangement are
3 or more evenly spaced odd points in a straight line,
the four corners and center of the square, and
Six corners and the center of a regular hexagon,
is any one selected from the group consisting of
The electron gun according to (6) above.
(8) When the area irradiated with the second electron beam formed on the image plane is defined as the second electron beam irradiation area,
The second electron beam irradiation area has a shape that can fill the irradiation target without loss or overlap.
The electron gun according to (7) above.
(9) the injection arrangement and the lens arrangement are four corners and the center of a square or six corners and the center of a regular hexagon;
the injection arrangement and the lens arrangement satisfy the following equations,
When the injection arrangement seen in the Z direction is used as a reference, the angle of rotation of the lens arrangement seen in the Z direction from the same or similar arrangement as the injection arrangement about the center of the injection arrangement is as follows. represented by θ in the formula of

The electron gun according to (8) above.
(10) An electron beam application apparatus including the electron gun according to (9) above,
The electron beam application device is
scanning electron microscope,
electron beam inspection device, or
scanning transmission electron microscope,
is
Electron beam application equipment.
(11) A method of forming a multi-electron beam, comprising:
a first electron beam forming step;
a second electron beam forming step;
including
The first electron beam forming step includes:
By forming an electric field between an electron source that generates electrons that can be emitted and an anode, m (m is an arbitrary integer equal to or greater than 2) first electron beams are emitted from the electron source,
or,
An electron beam is extracted by forming an electric field between an electron source that generates electrons that can be emitted and an anode, and m (m is an arbitrary integer of 2 or more) is obtained by dividing the extracted electron beam. 1 forming an electron beam,
The second electron beam forming step includes:
A multi-lens array having n lenses (n is an arbitrary integer equal to or greater than 2) is irradiated with the m first electron beams, and the individual lenses of the multi-lens array are irradiated from different positions. forming a maximum of m×n second electron beams by incidence of the first electron beam,
When the direction from the electron source to the multi-lens array is defined as the Z direction, and the emission position when the first electron beam is emitted from the electron source is defined as the first electron beam emission position,
The positional relationship between the first electron beam emission position and the lenses included in the multi-lens array when viewed in the Z direction is controlled so as to be a preset positional relationship.
A method for forming multiple electron beams.
(12) When the arrangement of the first electron beam emission positions is defined as the emission arrangement and the arrangement of the lenses provided in the multi-lens array is defined as the lens arrangement,
the injection arrangement and the lens arrangement are the same or similar arrangements;
When the injection arrangement seen in the Z direction is used as a reference, the lens arrangement seen in the Z direction is rotated about the center of the injection arrangement as a rotation axis so that the arrangement is not the same as or similar to the injection arrangement. placed in the
The method for forming a multi-electron beam according to (11) above.
(13) When the irradiation area of the second electron beam formed on the image plane is defined as the second electron beam irradiation area,
The second electron beam irradiation area has a shape that can fill the irradiation target without loss or overlap.
The method for forming a multi-electron beam according to (12) above.
(14) the injection arrangement and the lens arrangement are four corners and the center of a square or six corners and the center of a regular hexagon;
the injection arrangement and the lens arrangement satisfy the following equations,
When the injection arrangement seen in the Z direction is used as a reference, the angle obtained by rotating the lens arrangement seen in the Z direction from an arrangement identical or similar to the injection arrangement about the center of the injection arrangement as the rotation axis is as follows. represented by θ in the formula of

The method for forming a multi-electron beam according to (13) above.
(15) A scanning step of scanning the irradiation target with the multi-electron beam formed by the method for forming a multi-electron beam according to (14) above,
Scanning method of multiple electron beams.

The electron gun, electron beam application apparatus, and method of forming multiple electron beams disclosed in the present application can reduce the number of lenses included in the multilens array to the number of second electron beams. Therefore, it is possible to improve the production yield of the multi-lens array and reduce the running cost when using the electron gun or the electron beam application device.

FIG. 1 is a diagram schematically showing an electron gun 1 and an electron beam application device 10 according to an embodiment. FIG. 2 is a diagram for explaining an outline of how the electron gun 1 according to the embodiment forms multiple electron beams. FIG. 3 is a diagram for explaining an outline of how the electron gun 1 according to the embodiment forms multiple electron beams. FIG. 4 is a diagram for explaining an outline of how the electron gun 1 according to the embodiment forms multiple electron beams. FIG. 5 is a flow chart of a method for forming multiple electron beams. FIG. 6 is a diagram for explaining the outline of the second embodiment. FIG. 7 is a diagram showing an example in which the irradiation regions of the second electron beam B2 overlap. FIG. 8 is a diagram showing an example in which the irradiation area of the second electron beam B2 is missing. FIG. 9 is a diagram for explaining the outline of the third embodiment. FIG. 10 is a diagram for explaining the outline of the third embodiment. FIG. 11 is a diagram for explaining the outline of the third embodiment. FIG. 12 is a diagram for explaining the outline of the third embodiment. FIG. 13 is a diagram for explaining the outline of the third embodiment. FIG. 14 is a diagram for explaining the outline of the third embodiment. FIG. 15 is a diagram for explaining the outline of the third embodiment. FIG. 16 is a diagram for explaining the outline of the third embodiment.

An electron gun, an electron beam application apparatus, and a method for forming multiple electron beams will be described in detail below with reference to the drawings. In this specification, members having the same type of function are given the same or similar reference numerals. Further, repetitive descriptions of members denoted by the same or similar reference numerals may be omitted.

In addition, the position, size, range, etc. of each configuration shown in the drawings may not represent the actual position, size, range, etc., in order to facilitate understanding. As such, the disclosures in this application are not necessarily limited to the locations, sizes, ranges, etc. disclosed in the drawings.

(definition of direction)
In this specification, the Z direction is defined as the direction in which an electron beam formed by an electron source travels in a three-dimensional orthogonal coordinate system of X, Y, and Z axes. Note that the Z direction is, for example, the vertically downward direction, but the Z direction is not limited to the vertically downward direction.

(Embodiment of Electron Gun and Electron Beam Application Apparatus)
Embodiments of an electron gun 1, an electron beam application apparatus 10, and a method for forming multiple electron beams will be described with reference to FIGS. 1 to 4. FIG. FIG. 1 is a diagram schematically showing an electron gun 1 and an electron beam application device 10 according to an embodiment. 2 to 4 are diagrams for explaining an outline of how the electron gun 1 according to the embodiment forms multiple electron beams.

An electron gun 1 according to the embodiment includes at least an electron source 2 , an anode 3 and a multi-lens array 4 . The electron gun 1 may optionally include a power supply 5 for generating an electric field between the electron source 2 and the anode 3, a control section 6 for controlling the electron source 2, and the like. Although not shown, the electron gun 1 may include an acceleration electrode and an acceleration power supply for accelerating the electron beam formed by the electron source 2 and the anode 3 .

In the example shown in FIG. 1 , the counterpart device E of the electron beam application device 10 (the portion of the electron beam application device 10 excluding the electron gun 1 ) includes an electron beam deflection device 7 . The electron beam deflector 7 is used to scan the irradiation target S with the second electron beam B2 formed by the electron gun 1 . It should be noted that the example shown in FIG. Although illustration is omitted, the mating device E may be provided with known structural members according to the type of the electron beam application device 10 . In the example shown in FIG. 1, the number of electron beams B formed by the electron gun 1 is one in order to show the outline of the electron gun 1 and the electron beam application apparatus 10 as a whole. The outline of the multiple electron beams in the electron gun 1 and the electron beam application apparatus 10 according to the embodiment will be described later in detail with reference to FIGS. 2 to 4. FIG.

The electron source 2 is not particularly limited as long as it can form an electron beam B by generating electrons that can be emitted and extracting the generated electrons by an electric field formed between the anode 3, and a known electron source 2 is used. be able to. Examples of the electron source 2 include photocathode, field emitter, Schottky, and hot cathode. In this specification, the electron beam irradiated to the multi-lens array 4 (before passing through the multi-lens array 4) is referred to as a first electron beam B1, and after passing through the multi-lens array 4 (multi-lens The electron beam emitted from the array 4) may be referred to as a second electron beam B2. Further, when the first electron beam B1 and the second electron beam B2 are not particularly distinguished, they may be simply referred to as an electron beam B in some cases.

An example of an electron gun 1 using a photocathode 2a as an electron source 2 will be described with reference to FIG. The photocathode 2a generates electrons that can be emitted in response to receiving the excitation light L emitted from the light source 2b. The principle by which the photocathode 2a generates electrons that can be emitted in response to receiving the excitation light L is known (see, for example, Japanese Patent No. 5808021).

The photocathode 2a is formed of a substrate such as quartz glass or sapphire glass, and a photocathode film (not shown) adhered to the first surface 2a1 (the surface on the anode 3 side) of the substrate. The photocathode material for forming the photocathode film is not particularly limited as long as it can generate electrons that can be emitted by irradiation with the excitation light L. Materials that require EA surface treatment, materials that do not require EA surface treatment, etc. mentioned. Materials requiring EA surface treatment include, for example, III-V group semiconductor materials and II-VI group semiconductor materials. Specific examples include AlN, Ce ₂ Te, GaN, compounds of one or more alkali metals and Sb, AlAs, GaP, GaAs, GaSb, InAs, and mixed crystals thereof. Other examples include metals, specifically Mg, Cu, Nb, LaB ₆ , SeB ₆ , Ag, and the like. The photocathode 2a can be produced by subjecting the photocathode material to EA surface treatment, and the photocathode 2a can select excitation light in the near-ultraviolet to infrared wavelength region according to the gap energy of the semiconductor. In addition, electron beam source performance (quantum yield, durability, monochromaticity, time response, spin polarization) according to the application of the electron beam can be achieved by selecting the semiconductor material and structure.

Materials that do not require EA surface treatment include, for example, simple metals such as Cu, Mg, Sm, Tb, and Y, alloys, metal compounds, diamond, WBaO, Cs ₂ Te, and the like. A photocathode that does not require EA surface treatment may be produced by a known method (see, for example, Japanese Patent No. 3537779). The contents of US Pat. No. 3,537,779 are incorporated herein by reference in their entirety.

The light source 2b is not particularly limited as long as it can form the electron beam B by applying the excitation light L to the photocathode 2a. The light source 2b may be, for example, a high output (watt class), high frequency (several hundred MHz), ultrashort pulse laser light source, relatively inexpensive laser diode, LED, or the like. The excitation light L to be irradiated may be either pulsed light or continuous light, and may be appropriately adjusted according to the purpose. In the example shown in FIG. 1, the light source 2b is arranged outside the vacuum chamber CB, and the excitation light L is applied to the first surface 2a1 side of the photocathode 2a. Alternatively, the light source 2b may be arranged within the vacuum chamber CB. In addition, the excitation light L may be applied to the second surface 2a2 (the surface opposite to the anode 3) of the photocathode 2a.

The anode 3 is not particularly limited as long as it can form an electric field with the electron source 2, and an anode 3 generally used in the field of electron guns may be used. In the example shown in FIG. 1, by forming an electric field between the photocathode 2a and the anode 3, electron beams B are formed by extracting electrons generated in the photocathode 2a by irradiation of the excitation light L, which can be emitted.

In the example shown in FIG. 1, the power supply 5 is connected to the photocathode 2a in order to form an electric field between the photocathode 2a and the anode 3, but a potential difference is generated between the photocathode 2a and the anode 3. There is no particular restriction on the arrangement of the power supply 5.

Next, an outline of how the electron gun 1 according to the embodiment forms multiple electron beams will be described with reference to FIGS. 2 to 4. FIG. In the example shown in FIGS. 2 and 3, the photocathode 2a is linearly irradiated with three excitation lights La to Lc at different locations to form three first electron beams B1a to B1c (FIG. 2 The illustration of the first electron beams B1a to B1c is omitted here (shown in FIG. 3). , nine second electron beams B2a to B2c are formed (the second electron beams B2a to B2c are not shown in FIG. 2; they are shown in FIG. 3), and the nine second electron beams B2 are formed on the image plane IS. forming a focus. The image plane IS means a virtual plane on which the second electron beam B2 forms a focal point. The image plane IS may or may not match the surface of the irradiation target S. 3 is a cross-sectional view taken along lines AA, BB and CC of FIG. 2. FIG. An anode 3 exists between the photocathode 2a and the multi-lens array 4, but the illustration of the anode 3 is omitted in FIGS. 2 and 3 in order to avoid complicating the drawings.

When the first electron beams B1a to B1c irradiated from different positions are incident on the individual lenses 41 of the multi-lens array 4, the incident first electron beams B1a to B1c are converged and focused on the image plane IS. It has the function of forming. Therefore, by irradiating the multi-lens array 4 having n lenses 41 with m first electron beams B1, a maximum of m×n second electron beams B2 can be formed. In order to form the maximum m×n second electron beams B2, each of the m first electron beams B1 should cover all the n lenses 41 of the multi-lens array 4. should be irradiated.

In order for each of the m first electron beams B1 to be irradiated so as to cover all of the n lenses 41, for example, the spread of the first electron beam B1 is adjusted, and the m first electron beams B1 are irradiated. The adjustment of the irradiation position of the beam B1, the arrangement of the n lenses 41, etc. may be adjusted by appropriately combining them. The spread of the first electron beam B1 can be adjusted by changing the strength of the electric field formed between the electron source 2 and the anode 3. FIG. Note that the electron gun 1 disclosed in the present application does not necessarily need to form the m×n second electron beams B2 from the m first electron beams B1. There may be a lens 41 that any first electron beam B1 cannot reach. In other words, the electron gun 1 disclosed in the present application irradiates the multi-lens array 4 having n lenses 41 with m first electron beams B1, thereby generating m+1 or more or n+1 or more second electron beams B1. It is sufficient if the electron beam B2 can be formed. The upper limits of m and n are not particularly limited as long as they are within the range in which the technical ideas disclosed in the present application can be achieved. In order to increase the number of m and n while avoiding an increase in the size of the apparatus, advanced microfabrication technology is required, such as reducing the distance between the lenses 41 arranged in the multi-lens array 4, which leads to an increase in cost. Become. Therefore, the upper limits of m and n may be appropriately set in consideration of the merit of increasing the number of the second electron beams B2, the size of the apparatus, the cost, and the like.

The number of first electron beams B1 may be greater than, equal to, or less than the number of lenses 41 (integer of 2 or more) as long as it is an integer of 2 or more. Also, the arrangement of the first electron beams B1 (the positional relationship in which the m first electron beams B1 are emitted. In the example shown in FIGS. positional relationship of the lens 41) may be the same or different. Further, when the arrangement of the first electron beam B1 and the arrangement of the lens 41 are the same, when viewed from the electron source 2 in the direction of the multi-lens array 4 (Z direction), the first The arrangement of the electron beam B1 and the arrangement of the lens 41 may match or may be shifted. Furthermore, the arrangement of the first electron beam B1 and the arrangement of the lens 41 may have similar shapes with different sizes, although the shape when viewed in the Z direction is the same.

Note that the staggered arrangement includes, for example, the arrangement shown in FIG. 2 as described in (1) to (3) below.
(1) Changing the position of either the electron source 2 or the multi-lens array 4 in the XY plane direction. In other words, the arrangement of the first electron beam B1 and the arrangement of the lens 41 do not match when viewed in the Z direction. In this case, when viewed in the Z direction, all of the m first electron beam B1 emission positions may not coincide with the lens 41, and some of the emission positions of the first electron beam B1 may coincide with the lens 41 .
(2) Rotate either the electron source 2 or the multi-lens array 4 with the Z direction as the central axis. The center of rotation is not particularly limited, and the center of rotation may be a point where any one of the positions from which the first electron beam B1 is emitted coincides with the lens 41, or the position at which the first electron beam B1 is emitted and the lens 41. may be set as the center of rotation.
(3) A combination of (1) and (2) above.

In the example shown in FIGS. 2 and 3, the first electron beam B1 and the lens 41 are linearly arranged, but this is merely an example. As described above, the electron gun 1 according to the embodiment irradiates the multi-lens array 4 having n lenses 41 with the m first electron beams B1 to obtain m+1 or more or n+1 or more second electron beams B1. The arrangement of the first electron beam B1 and the arrangement of the lens 41 are not particularly limited as long as the electron beam B2 can be formed.

For example, in the example shown in FIG. 4, five first electron beams B1 are formed by irradiating five excitation light beams L non-linearly (at the four corners of the square and at the middle point of the square). (The illustration of the first electron beam B1 is omitted). Each of the five first electron beams B1 formed is incident on each of the five lenses 41a to 41e provided in the multi-lens array 4. As shown in FIG. Therefore, as shown in the image plane IS on the right side of FIG. 4, five second electron beams B2 are formed from each of the lenses 41a to 41e, so that a total of 25 second electron beams B2 are formed. be. Of course, also in the example shown in FIG. 4, the first electron beam B1 and the lens 41 may be arranged to be shifted as described above.

As long as at least two or more first electron beams B1 are formed, the forming method is not particularly limited. When the electron source 2 is a photocathode 2a, the photocathode 2a may be irradiated with m excitation lights L as shown in FIGS. In order to irradiate the photocathode 2a with m excitation lights L, m light sources 2b may be used. Alternatively, as shown in FIG. 1, a light splitter 2c such as a liquid crystal shutter is arranged between the single light source 2b and the photocathode 2a, and the excitation light emitted from the single light source 2b is separated by the light splitter 2c. You may divide L into any desired number. Note that two or more light sources 2b and optical splitters 2c may be combined. Further alternatively, first, the electron beam B may be emitted from the photocathode 2a, and the emitted electron beam B may be split using an aperture array or the like to form m first electron beams B1. If the electron beam B is to be split as set in advance, for example, an aperture array formed of a metal plate or the like may be used. When controlling the number of splits of the electron beam B and the position of the first electron beam B1 to be formed, an aperture array with a blanking function (for example, an aperture array with a deflection function, an electrostatic lens array) may be used. .

In FIGS. 1 to 4, an example using the photocathode 2a as the electron source 2 is explained, but as described above, a known electron source 2 such as a field emitter, Schottky, hot cathode, etc. may be used. good. In that case, the light source 2b and the optical splitter 2c shown in FIG. 1 are unnecessary. Field emitters and Schottky can also be arrayed side by side. Therefore, in the case of the field emitter and Schottky, m first electron beams B1 may be emitted from an array of elements. may be divided to form m first electron beams B1.

A hot cathode is larger in size as an electron source 2 than a photocathode, a field emitter, and a Schottky. Therefore, although it is technically possible to arrange two or more hot cathodes, the size of the electron gun 1 may increase. Therefore, when a hot cathode is used as the electron source 2, the electron beam B is emitted first, and the emitted electron beam B is split using an aperture array or the like from the viewpoint of convenience rather than from a technical point of view. to form the first electron beam B1.

As the anode 3, one generally used in the field of the electron gun 1 may be used.

The multi-lens array 4 is not particularly limited as long as it has the function of converging the m first electron beams B1 incident on the respective lenses 41 and forming m focal points on the image plane IS. For example, the charged particle beam lens array described in JP-A-2013-30567, JP-A-2014-53408, etc. can be used. All matters described in JP-A-2013-30567 and JP-A-2014-53408 are incorporated herein by reference.

FIGS. 1-4 are but one example of the electron gun 1 disclosed in the present application. Various modifications may be made within the scope of the technical ideas disclosed in the present application. For example, in the example shown in FIG. 1, a controller 6 for controlling the light source 2b is provided. When a plurality of light sources 2b are provided, the control unit 6 can control the number of first electron beams B1 to be formed by controlling which light source 2b emits the excitation light L. FIG. When the optical splitter 2c is provided, the controller 6 may control the optical splitter 2c to control the number of the first electron beams B1 to be formed. The photocathode 2a has a feature of emitting an electron beam B from a position where the excitation light L is received. Therefore, when the photocathode 2a is used as the electron source 2, the controller 6 may control the position of the excitation light L received by the photocathode 2a. When the irradiation position of the excitation light L is changed, the incident angle of each of the first electron beams B1 entering the multi-lens array 4 can be adjusted. Therefore, even after the electron gun 1 is assembled, in other words, even after the multi-lens array 4 is set up, the controller 6 adjusts the irradiation number and/or the irradiation position of the excitation light L so that the image plane The number and positional relationship of focal points formed on the IS can be adjusted. Further, the control unit 6 may control the intensity of the excitation light L, or may control the excitation light L so as to irradiate the photocathode 2a as continuous light or pulsed light.

When array-like field emitters and Schottky are used as the electron source 2, the controller 6 may control from which element constituting the array the electron beam B is emitted. When the elements are arranged in the row direction and the column direction, the number and/or the emission position of the elements for emitting the electron beam B can be adjusted, so that the same effects as those of the photocathode 2a can be obtained.

When a plurality of hot cathodes are used as the electron source 2, the controller 6 may control from which hot cathode the electron beam B is emitted.

When an aperture array with a blanking function is used as the aperture array for splitting the electron beam B, regardless of the type of the electron source 2, a member (for example, an electrostatic lens, etc.) that performs the blanking function is controlled by the controller 6. may control the number and locations of the first electron beams B1 split from the electron beam B by controlling .

As the electron beam application device 10 mounting the electron gun 1, a known device mounting an electron gun can be used. For example, free electron laser accelerator, electron microscope, electron beam holography device, electron beam drawing device, electron beam diffraction device, electron beam inspection device, electron beam metal additive manufacturing device, electron beam lithography device, electron beam processing device, electron beam curing devices, electron beam sterilizers, electron beam sterilizers, plasma generators, atomic element generators, spin-polarized electron beam generators, cathodoluminescence devices, reverse photoelectron spectroscopy devices, and the like.

The second electron beam B2 formed by the electron gun 1 disclosed in the present application may be appropriately adjusted according to the type of electron beam application device 10. FIG. For example, when the electron beam application apparatus 10 is a scanning electron microscope or a scanning electron beam inspection apparatus, the sample is imaged by scanning a plurality of line-shaped second electron beams B2 formed as shown in FIG. You can save time and inspection time. On the other hand, when a plurality of second electron beams B2 are formed in a plane as shown in FIG. 4, it can be used for transmission electron microscopes, electron beam sterilizers, electron beam sterilizers, and the like. It can also be used for electron beam drawing devices (mask drawing devices, direct drawing devices), electron beam metal additive manufacturing devices (metal 3D printers), and the like, regardless of scanning or non-scanning.

(Embodiment of method for forming multiple electron beams)

Next, a method for forming multiple electron beams will be described with reference to FIG. FIG. 5 is a flow chart of a method for forming multiple electron beams. A method of forming a multi-electron beam includes a first electron beam forming step (ST1) and a second electron beam forming step (ST2).

In the first electron beam forming step (ST1), an electric field is formed between an electron source 2 that generates electrons that can be emitted and an anode 3, thereby generating m electron beams (m is an arbitrary value of 2 or more) from the electron source 2. (integer of ) of the first electron beam B1 is emitted. Alternatively, by forming an electric field between an electron source 2 that generates electrons capable of being emitted and an anode 3, electron beams B of a number less than m are extracted, and the extracted electron beams are divided into m (m is any integer equal to or greater than 2) first electron beams B1 may be formed. As the electron source 2, a known electron source such as a photocathode, a field emitter, a Schottky, or a hot cathode may be used as described in the embodiment of the electron gun 1. FIG. When a plurality of hot cathodes are used as the electron source 2, the electron gun 1 may become large. Therefore, when a hot cathode is used as the electron source 2, first, an electron beam B is extracted from the hot cathode, and the extracted electron beam B is divided into m (m is an arbitrary integer of 2 or more) first electrons. It is preferred to form beam B1.

In the second electron beam forming step (ST2), the m first electron beams B1 are irradiated to the multi-lens array 4 having n lenses 41 (where n is an arbitrary integer equal to or greater than 2). m×n second electron beams B2 are formed.

When the formed second electron beam B2 is scanned over the irradiation object S, although not shown, the second electron beam focused on the image plane IS after the second electron beam formation step (ST2). A second electron beam B2 scanning step (ST3) in which B2 is scanned while being deflected by the electron beam deflector 7, and a second electron beam B2 irradiation step (ST4) in which the irradiation target S is irradiated with the scanned second electron beam B2. and may include Moreover, when the scanning of the formed second electron beam B2 is unnecessary, the second electron beam B2 irradiation step (ST4) may be performed after the second electron beam formation step (ST2).

The electron gun 1 disclosed in the present application, the electron beam application device 10 equipped with the electron gun 1, and the method for forming a multi-electron beam (hereinafter, "the electron gun 1, the electron beam application device 10, and the method for forming a multi-electron beam" are summarized. described as "electron gun, etc.") has the following effects.
(1) When the number of the second electron beams B2 formed on the image plane IS (to be irradiated to the irradiation target S) is the same, the electron gun or the like irradiates the multi-lens array 4 with m first electron beams B1. , the number of lenses 41 included in the multi-lens array 4 can be made smaller than in Patent Document 1. Therefore, since the probability that any one lens 41 is defective when manufacturing the multi-lens array 4 is reduced, the manufacturing yield of the multi-lens array 4 is improved. Further, the fewer the number of lenses 41, the lower the probability that any one lens 41 will become defective when the electron gun or the like is used.
(2) As shown in FIGS. 3 and 4, the electron gun or the like disclosed in the present application causes m first electron beams B1 having different emission positions to be incident on the lens 41, thereby narrowing the distance between the lenses 41. A second electron beam B2 can be focused on the image plane IS at intervals. Therefore, assuming that the intervals between the second electron beams B2 formed on the image plane IS are the same, the interval between the lenses 41 of the electron gun 1 can be made wider than the hole provided in the lens 7 described in Japanese Unexamined Patent Application Publication No. 2002-200010. Therefore, manufacturing of the multi-lens array 4 is facilitated. Further, since the distance between the lenses 41 can be increased, the size of the lenses 41 can be increased. When the size of the lens 41 is increased, the beam current of the electron beam B1 passing through each lens 41 can be increased (brightness is increased).
(3) Assume an embodiment in which the electron source 2 forms m first electron beams B1 without using an aperture array or the like. In that case, from the viewpoint of forming m first electron beams B1, any one of a photocathode, a field emitter, a Schottky, and a hot cathode may be used. 1 size can be reduced. Also, in the field emitter or Schottky, when the elements are arranged in an array, as with the lens 41 of the multi-lens array 4, as the number of elements increases, defects in one of the elements forming the array during manufacture or use will increase. more likely to occur. On the other hand, the photocathode 2a can be manufactured as one member by bonding the photocathode film to the substrate. Therefore, when the photocathode 2a is used for the electron source 2 that forms the plurality of first electron beams B1, the size of the electron gun and the like can be reduced, and the probability of defects occurring during manufacture or use is reduced.
(4) Further, the photocathode 2a can easily change the number and arrangement of the emitted first electron beams B1 by adjusting the number and irradiation position of the excitation light L. Therefore, when the photocathode 2a is used as the electron source 2, even after the electron source 2 and the multilens array 4 are set up in the electron gun, the number and the incident angles of the first electron beams B1 incident on the multilens array 4 are can be adjusted to adjust the number and arrangement of the second electron beams B2 formed on the image plane IS (to irradiate the irradiation target S).

(Configuration example 1 that can be adopted in the embodiments of the electron gun and the electron beam application device)
Next, with reference to FIGS. 1 to 6, configuration examples that can be employed in the embodiments of the electron gun and the electron beam application apparatus (hereinafter, embodiments of the electron gun and the electron beam application apparatus employing the configuration examples) will be described. may be described as a “second embodiment”) will be described. FIG. 6 is a diagram for explaining the outline of the second embodiment.

As shown in FIGS. 2 and 4, the electron gun 1 disclosed in the present application irradiates a lens array 4 having n lenses 41 with m first electron beams B1, thereby generating m×n electron beams at maximum. number of second electron beams B2 can be formed on the image plane IS.

The inventors of the present invention have investigated the emission positions when the m first electron beams B1 are emitted (hereinafter sometimes referred to as "first electron beam emission positions") and the lenses included in the multi-lens array 4. 41 positional relationship and . As a result, the positional relationship between the first electron beam emission position and the lens 41 provided in the multi-lens array 4 when viewed in the Z direction (this positional relationship may be hereinafter referred to as "relative positional relationship") is It was newly discovered that the second electron beam B2 formed on the image plane IS can be controlled to have a suitable arrangement by controlling. An electron gun 1 according to the second embodiment includes a controller 6 as a component. Then, except that the control unit 6 controls the relative positional relationship to be a preset positional relationship, the above (embodiment of electron gun and electron beam application device (hereinafter referred to as "first embodiment") )). Therefore, in the second embodiment, the points different from the first embodiment will be mainly described, and repetitive descriptions of items already described in the first embodiment will be omitted. Therefore, it is needless to say that the items already explained in the first embodiment can be adopted in the second embodiment even if they are not explicitly explained in the second embodiment.

With reference to FIG. 6, the outline of the control content of the control part 6 of 2nd Embodiment is demonstrated. In FIG. 6A, when the arrangement of the first electron beam emission positions is defined as the emission arrangement and the arrangement of the lenses 41 provided in the multi-lens array 4 is defined as the lens arrangement, the emission arrangement as shown in FIG. And the lens arrangement is the same (same shape), and when the injection arrangement seen in the Z direction is used as a reference, the lens arrangement seen in the Z direction is the same as the injection arrangement (overlap). A second electron beam B2 formed on the surface IS is shown. In this specification, the "first electron beam emission position" means a position where m first electron beams B1 are emitted. More specifically, when the m first electron beams B1 are extracted directly from the electron source 2, the position where the electrons of the electron source 2 are extracted is the injection position. is split by an electron beam splitting device such as an aperture array to form m first electron beams B1, the position of the m first electron beams B1 emitted from the electron beam splitting device is the emission position. .

In FIG. 6B, when the injection arrangement seen in the Z direction is used as a reference, the lens arrangement is adjusted with the center of the injection arrangement as the rotation axis so that the lens arrangement seen in the Z direction does not become the same arrangement as the injection arrangement. It shows the second electron beam B2 formed on the image plane IS when arranged in a rotated position. FIG. 6(3) shows the second electron beam B2 formed on the image plane IS when the lens arrangement is further rotated on the basis of the injection arrangement from the example shown in FIG. 6(2). As is clear from the examples shown in FIGS. 6(1) to 6(3), the second electron beam B2 formed on the image plane IS is arranged by rotating the lens arrangement with reference to the emission arrangement viewed in the Z direction. changes. More specifically, in the example shown in FIG. 6(1), individual regions of the second electron beam B2 formed by passing through individual lenses 41 (a to e) (hereinafter referred to as "B2 individual lens regions") ) and the gap between the regions (the portion indicated by the circle in FIG. 6(1)) is approximately the same size as the B2 individual lens region. On the other hand, as shown in FIGS. 6(2) and 6(3), by rotating the relative positional relationship of the lens arrangement with respect to the injection arrangement, the gap between the B2 individual lens regions (indicated by the circle in FIG. 6(3) part) becomes smaller. If the electron beam application device is, for example, a non-scanning electron beam sterilizer or a non-scanning electron beam sterilizer, the smaller the gap between the B2 individual lens regions, the less uneven heating. Therefore, sterilization or sterilization efficiency can be increased. The degree to which the lens arrangement is rotated about the center of the injection arrangement may be appropriately set according to the purpose.

Note that FIG. 6 is an example in which the injection arrangement and the lens arrangement seen in the Z direction are the same (same shape). Alternatively, the injection arrangement and the lens arrangement are similar arrangements (similar shapes), and when the injection arrangement seen in the Z direction is used as a reference, the lens arrangement seen in the Z direction is not similar to the injection arrangement. , may be arranged at a position rotated about the center of the injection arrangement as the rotation axis. Further alternatively, the injection arrangement and lens arrangement may not be the same or similar as long as the gap between the B2 individual lens regions is reduced by changing the relative positional relationship of the injection arrangement and lens arrangement. In other words, the control unit 6 may perform control so that the relative positional relationship becomes a preset positional relationship.

The relative positional relationship may be set when the electron gun 1 is assembled so as to have a preset positional relationship. In other words, after the electron gun 1 is assembled, it can be fixed so that the relative positional relationship does not change. However, after assembling the electron gun 1, fine adjustment may be necessary. Therefore, after the electron gun 1 is assembled, it is desirable that the control section 6 can be controlled so as to adjust the relative positional relationship.

When the electron source 2 is the photocathode 2a, the controller 6 may control the position of the excitation light L received by the photocathode 2a. If the electron source 2 is a field emitter or Schottky, the controller 6 may control the field emitter or Schottky element that emits the first electron beam B1.

As shown in FIG. 1, the electron gun 1 includes a rotation mechanism 42 that rotates the multi-lens array 4 about the Z direction, and the controller 6 controls the rotation mechanism 42 to control the relative positional relationship. good too. The rotation mechanism 42 is not particularly limited as long as it can rotate the multi-lens array 4 . For example, a gear that engages with the outer periphery of the multi-lens array 4 may be provided, and the gear may be rotated by a drive source such as a motor. When the electron gun 1 has the rotation mechanism 42, the relative positional relationship can be controlled by adjusting the arrangement of the multi-lens array 4. FIG. Of course, the controller 6 may control both the electron source 2 and the rotating mechanism 42 of the multi-lens array 4 .

When the electron beam extracted from the electron source 2 is split by the electron beam splitting device to form m first electron beams B1, the controller 6 controls the rotating mechanism 42 of the multi-lens array 4 to You can control the relative positional relationship. Alternatively, although not shown, a rotating mechanism for rotating the electron beam splitting device (hereinafter sometimes referred to as a "splitting device rotating mechanism") is provided, and the controller 6 controls the splitting device rotating mechanism. By doing so, the relative positional relationship may be controlled. The dividing device rotating mechanism may have a mechanism similar to the rotating mechanism 42 . Of course, the controller 6 may control both the rotating mechanism 42 and the dividing device rotating mechanism.

Further, as shown in FIG. 1, the electron gun 1 may include a moving mechanism 43 for moving the multi-lens array 4 in the Z direction, and the control unit 6 may control the moving mechanism 43 . As will be described later, by adjusting the distance between the first electron beam emission position and the multi-lens array 4, the beam interval of the second electron beam B2 formed on the image plane IS can be controlled. The moving mechanism 43 is not particularly limited as long as it can move the multi-lens array 4 in the Z direction. For example, a drive source such as a rack and pinion mechanism and a motor may be provided.

When the controller 6 controls the rotating mechanism 42 for rotating the multi-lens array 4, the electron gun 1 must employ the rotating mechanism 42. FIG. On the other hand, when the controller 6 controls the photocathode, field emitter or Schottky, the rotating mechanism 42 for rotating the multi-lens array 4 is not required, and the electron gun 1 can be simplified. Therefore, it is more preferable for the controller 6 to control the photocathode, field emitter or Schottky. Furthermore, unlike field emitters or Schottkys, the photocathode has the feature of being able to rapidly emit an electron beam from any location where the excitation light L is received. Therefore, when a photocathode is used as the electron generation source 2 and the control unit 6 controls the excitation light L received by the photocathode, the relative positional relationship is controlled to be a preset positional relationship and/or the relative positional relationship fine-tuning can be performed quickly.

By controlling the relative positional relationship, the electron gun 1 according to the second embodiment has the effect that the second electron beam B2 formed on the image plane IS can be controlled to have a suitable arrangement.

(Configuration Example 2 Adoptable in Embodiments of Electron Gun and Electron Beam Apparatus)
Next, a more limited example of the relative positional relationship described in the second embodiment will be described. For the sake of convenience, this embodiment will be referred to as the third embodiment. As a result of intensive studies, the present inventors newly found that the formed second electron beam B2 can scan the irradiation target S without loss or overlap when the emission arrangement and the lens arrangement are in a specific relationship. Hereinafter, the relationship between the injection arrangement and the lens arrangement will be described in more detail with reference to the drawings. FIG. 7 is a diagram showing an example in which the irradiation regions of the second electron beam B2 overlap. FIG. 8 is a diagram showing an example in which the irradiation area of the second electron beam B2 is missing. 9 to 16 are diagrams for explaining the outline of the third embodiment.

In the third embodiment, it is assumed that the electron gun 1 is installed in a scanning electron beam application apparatus 10, for example. As shown in FIG. 2, when the second electron beam B2 can be formed linearly on the image plane IS, by scanning the formed linear second electron beam B2 with the electron beam deflection device 7, The irradiation target S can be irradiated with the second electron beam B2 without duplication or loss.

By the way, as shown in FIG. 4, it is assumed that the second electron beam B2 is formed non-linearly on the image plane IS. In that case, in the example shown in FIG. 7, first, 5×5=25 second electron beams B2 (the white portion surrounded by the dotted line in FIG. 7. For example, N1 (41a), N1 (41b) , N1 (41c).) are formed on the image plane IS, and the illumination object S is illuminated. Then, the second 5×5=25 second electron beams B2 deflected by the electron beam deflector 7 (hatched portions surrounded by dotted lines in FIG. 7. For example, N2 (41b), N2 (41c) ) is irradiated to the irradiation target S. In this state, as shown in FIG. 7, there is no overlap of the second electron beam B2 with which the irradiation target S is irradiated. However, the third 5×5=25 second electron beams B2 deflected by the electron beam deflector 7 (the portion surrounded by the dotted line in FIG. ), N3 (41b), and N3 (41c).) are irradiated onto the irradiation object S, for example, N3 (41c) is repeatedly irradiated onto the region already irradiated with the first second electron beam N1 (41b). will be Then, the second electron beam B2 is repeatedly irradiated to any region after the n-th time, such as N2 (41b) for the fourth time, N3 (41B) for the fifth time, and so on.

On the other hand, as shown in FIG. 8, the third 5×5=25 second electron beams B2 (the part surrounded by the dotted line in FIG. N3 (41b), N3 (41c).), for example, N3 (41c) does not overlap the second irradiation area of the second electron beam N2 (41b). It is also possible to increase the deflection width. However, if the deflection width of the electron beam deflector 7 is increased, a loss occurs in the irradiation area of the second electron beam B2 between N2 (41a) and N3 (41a).

In the third embodiment, as shown in FIG. 9, the area irradiated with the second electron beam B2 formed on the image plane (the area where ● in FIG. 9 gathers) is defined as the second electron beam irradiation area. Then, the second electron beam irradiation area has a shape that can completely fill the irradiation target S without loss or overlap. Note that in the third embodiment, the second electron beam irradiation area is non-linear. In other words, the second electron beam B2 is not aligned linearly. In the example shown in FIG. 9, the divided regions (S1, S2, S3, . Therefore, in the example shown in FIG. 9, the m×n second electron beams B2 formed can be scanned over the irradiation target S without overlapping or loss.

The shape in which the second electron beam irradiation area can completely cover the irradiation target S without loss or overlap is obtained by adjusting the injection arrangement and the lens arrangement to, for example, three or more odd-numbered points at equal intervals in a straight line, the four corners and the center of a square. , six corners and the center of a regular hexagon. Note that the above example is a typical example, and other arrangements may be used as long as the third embodiment can be implemented. The exit arrangement and lens arrangement are of the same size or similar shape when viewed in the Z direction.

Next, with reference to FIGS. 3 and 10 to 16, the relationship for the second electron beam irradiation area to fill the irradiation target S without loss or overlap will be described. First, the case where the injection arrangement and lens arrangement are four corners and the center of a square or six corners and the center of a regular hexagon will be described. As shown in FIGS. 3 and 10, a first electron beam B1 emitted from the electron source 2 passes through a lens provided in a multi-lens array (MLA) 4, and a second electron beam B2 is formed on the image plane IS. be done. At that time, the position vector P of the beam on the image plane IS can be expressed by the following equation (1). The symbol "C" in FIG. 10 is the direction connecting the injection position at the center of the injection arrangement and the lens arranged at the center of the lens arrangement (hereinafter sometimes referred to as "central axis"). More specifically, when the injection arrangement and lens arrangement are four corners and the center of a square, the directions are the directions connecting the centers, and when the six corners and the center of a regular hexagon are the directions connecting the centers. The meanings of the symbols in formula (1) are described following formula (1). Note that the meanings of the symbols in the formulas to be described later are also described together.

FIG. 11 is a view of the image plane IS in the Z direction when the exit arrangement and lens arrangement are the six corners and the center of a regular hexagon. The meanings of symbols in FIG. 11 are as described above. The second electron beam B2 formed on the image plane IS can be represented by the basis vectors shown in the following equation (2). Equation (3) is derived from Equation (2), and considering the relationship of Equation (4), the angle θ formed by vector P and vector Ps can be expressed by Equation (5).

In the equation (1) representing the position vector P of the beam on the image plane IS, when the first electron beam B1 passes through the central axis C of the multi-lens array 4, the absolute value of the vector R is expressed by the following equation (6). can be expressed as Also, when the first electron beam B1 emitted from the central axis C passes through a lens of the multi-lens array 4 deviating from the central axis C, the absolute value of the vector S can be expressed by the following equation (7).

In the above equations (3), (5), (6) and (7), the distance u from the electron source 2 to the multi-lens array 4, the distance v from the multi-lens array 4 to the image plane IS, the first electron beam B1 And by applying design information such as the number of lenses, when the injection arrangement seen in the Z direction is used as a reference, the lens arrangement seen in the Z direction is rotated from the same or similar arrangement as the injection arrangement by rotating the center of the injection arrangement. The angle θ to rotate about axis C can be calculated.

In the example shown in FIGS. 11 and 12, there are seven first electron beams B1 (six corners and the center of the regular hexagon), seven lenses in the multi-lens array 4 (six corners and the center of the regular hexagon), and u=63 mm. , v=20 mm and P=100 μm. In that case, since P′=P, φ=60°, h=2, and i=1, θ, R, and S can be calculated as follows.

FIG. 12 shows the arrangement based on the numerical values obtained by the above calculation. The emission position of the first electron beam B1 is set at an interval (center-to-center distance) of 315 μm (vector R) from the center and central axis of the electron source 2, and the lens is positioned from the center and central axis of the multi-lens array (MLA) 4. They are arranged at an interval (center-to-center distance) of 200.8 μm (vector S). Then, when viewed in the Z direction, relative rotation of θ=19.11° in the counterclockwise direction from the position at which the first electron beam B1 is emitted and the lens are similar, the image plane IS is in the direction of the vector P. 49 second electron beams B2 can be formed at intervals of 100 μm. The shapes of the 49 second electron beams B2 formed are divided regions S1, S2, . It is a shape that can irradiate Therefore, by using the electron gun 1 designed with the electron source 2 and the multi-lens array 4 as shown in FIG. 12, the irradiation object S can be scanned with the second electron beam B2 without missing or overlapping irradiation.

13 and 14 show an example in which there are five first electron beams B1 (four corners and the center of the square) and five lenses in the multi-lens array 4 (four corners and the center of the square). Assume u=63 mm, v=20 mm, and P=100 μm. In that case, as shown in FIG. 13, P′=P, φ=90°, h=2, and i=1, so θ, R, and S can be calculated as follows.

FIG. 14 shows the arrangement based on the numerical values obtained by the above calculation. The emission position of the first electron beam B1 is set at an interval (center-to-center distance) of 315 μm (vector R) from the center and central axis of the electron source 2, and the lens is positioned from the center and central axis of the multi-lens array (MLA) 4. They are arranged at intervals (center-to-center distance) of 170 μm (vector S). Then, when viewed in the Z direction, relative rotation of θ=63.43° in the counterclockwise direction from the position where the first electron beam B1 is emitted and the lens are similar, the image plane IS is in the direction of the vector P. 25 second electron beams B2 can be formed at intervals of 100 μm. The shapes of the 25 second electron beams B2 thus formed correspond to divided regions of the same shape that can fill the irradiation target S shown in FIG. 13 without loss or overlap.

Next, the case where the injection arrangement and the lens arrangement are three or more evenly-spaced odd-numbered points will be described. As shown in FIG. 2, when the injection arrangement seen in the Z direction is used as a reference, if the lens arrangement seen in the Z direction is the same as or similar to the injection arrangement (in other words, the rotation angle is 0 degrees), Second electron beams B2 are linearly formed on the image plane IS at regular intervals. On the other hand, as shown in FIG. 15, when the lens arrangement seen in the Z direction is based on the injection arrangement seen in the Z direction, when the lens arrangement seen in the Z direction is arranged at a position rotated around the center of the injection arrangement as a rotation axis, the position shown in FIG. , a parallelogram-shaped second electron beam irradiation area is formed on the image plane IS. Although the size of the parallelogram formed varies with the angle of rotation, the resulting shape remains a parallelogram. A parallelogram is a shape that can completely cover the irradiation target without loss or duplication. Therefore, when the injection arrangement and lens arrangement are three or more odd-numbered points that are equally spaced linearly, the rotation angle may be any angle, and the interval for scanning the second electron beam irradiation area is adjusted according to the rotation angle. do it. Also, the number of odd points is not particularly limited as long as it is 3 or more, and examples thereof include 5, 7, 9, 11, 13, 15, and the like. The upper limit of the odd number of points is not particularly limited in principle. The size of the irradiation target S, the size of the second electron beam B2, and the like may be taken into consideration when setting the value as appropriate.

FIG. 15 shows three equally spaced first electron beams B1, three equally spaced lenses of the multi-lens array 4, a distance from the electron source to the multi-lens array=63 mm, and a distance from the multi-lens array to the image plane. An example is shown for distance=20 mm. The emission position of the first electron beam B1 is set at an interval (center-to-center distance) of 315 μm (vector R) from the center and central axis of the electron source 2, and the lens is positioned from the center and central axis of the multi-lens array (MLA) 4. They are arranged at intervals (center-to-center distance) of 156 μm (vector S). Then, when viewed in the Z direction, relative rotation of θ=75.96° in the counterclockwise direction from the position at which the first electron beam B1 is emitted and the lens are similar to each other causes the image plane IS to be in the direction of the vector P. Nine second electron beams B2 can be formed at intervals of 100 μm.

The above description is for the case where the first electron beam emission position is formed in the electron source 2 . When the first electron beam emission position is formed in the electron beam splitting device, the electron source 2 can be read as the electron beam splitting device in the above description. Also, the sizes (preferably diameters) of the first electron beam B1, the second electron beam B2, and the lens 41 shown in the drawings are only schematic. The sizes of the first electron beam B1, the second electron beam B2, and the lens 41 may be appropriately adjusted within the objective ranges of the second and third embodiments.

As described above, in the third embodiment, the irradiation target S can be scanned with the formed second electron beam B2 without overlapping or loss. Therefore, the third embodiment is particularly useful for scanning electron beam application apparatus 10. FIG. Examples of the scanning electron beam application apparatus 10 include, but are not limited to, a scanning electron microscope, an electron beam inspection apparatus, a scanning transmission electron microscope, and the like. Of course, the third embodiment may be applied to a non-scanning electron beam application apparatus 10. FIG.

The third embodiment has the following effects in addition to the effects described in the second embodiment.
(1) Compared with the second embodiment, in the third embodiment, the shapes of the injection arrangement and the lens arrangement are specified, and furthermore, the lens arrangement is rotated with respect to the injection arrangement viewed in the Z direction. identify the angle. Therefore, compared to the second embodiment, the gap between the second electron beams B2 formed on the image plane IS can be made smaller.
(2) When applied to a scanning electron beam application apparatus, the formed second electron beam B2 can be scanned over the irradiation target S without overlapping or missing.

(Second Embodiment of Method for Forming Multiple Electron Beams)
Next, a second embodiment of the method for forming multiple electron beams will be described. In the second embodiment of the multi-electron beam forming method, the direction from the electron source 2 to the multi-lens array 4 is defined as the Z direction, and the emission position when the first electron beam B1 is emitted from the electron source 2 is When the first electron beam emission position is defined, the positional relationship between the first electron beam emission position and the lenses of the multi-lens array when viewed in the Z direction is controlled so as to achieve a preset positional relationship. So, unlike the above (embodiment of method for forming multiple electron beams (hereinafter sometimes referred to as "first embodiment of method")), other points are the same as the first embodiment of method. is. Therefore, in the second embodiment of the method for forming multiple electron beams, the description will focus on the differences from the first embodiment of the method, and the description will be repeated for the items already described in the first embodiment of the method. are omitted. Therefore, even if not explicitly explained in the second embodiment of the method for forming multiple electron beams, it goes without saying that the matters already explained in the first embodiment of the method can be adopted.

In the second embodiment of the method for forming a multi-electron beam, "the direction from the electron source 2 to the multi-lens array 4 is defined as the Z direction, and the emission position when the first electron beam B1 is emitted from the electron source 2 is defined as the first electron beam emission position, the positional relationship between the first electron beam emission position and the lenses provided in the multi-lens array when viewed in the Z direction is controlled so as to be a preset positional relationship. ” are the same as those described in the second and third embodiments. Therefore, a detailed description of each step included in the second embodiment of the method for forming multiple electron beams will be omitted since they have already been substantially described in the second and third embodiments.

Further, when performing a scanning step of scanning the irradiation target with the multi-electron beams formed by the second embodiment of the multi-electron beam forming method (multi-electron beam scanning method), the injection arrangement and the lens arrangement are The formed multi-electron beam may be scanned after controlling the arrangement described in the third embodiment.

The second embodiment of the method for forming multiple electron beams has the same effects as those described in the second and third embodiments.

INDUSTRIAL APPLICABILITY The electron gun, the electron beam application apparatus, and the method for forming multiple electron beams disclosed in the present application can improve the production yield of the multi-lens array and reduce the running cost of the electron gun or the electron beam application apparatus. Therefore, it is useful for industries dealing with multiple electron beams.

REFERENCE SIGNS LIST 1 electron gun 2 electron source 2a photocathode 2a1 first surface 2a2 second surface 2b light source 2c optical splitter 3 anode 4 multilens array 41, 41a ~ 41e... Lens 42... Rotating mechanism 43... Moving mechanism 5... Power supply 6... Control unit 7... Electron beam deflector 10... Electron beam applying device B... Electron beam B1, B1a to B1c... th 1 electron beam, B2, B2a to B2c... second electron beam, CB... vacuum chamber, E... partner device, IS... image plane, L, La to Lc... excitation light, S... irradiation object

Claims (15)

an electron source that produces electrons that can be emitted;
an anode capable of forming an electric field with the electron source, extracting the emissible electrons by the formed electric field, and forming an electron beam;
a multi-lens array;
a control unit;
an electron gun comprising
When the electron beam irradiated to the multi-lens array is defined as a first electron beam, m (m is an arbitrary integer equal to or greater than 2) first electron beams are formed,
The multi-lens array comprises n lenses (n is any integer equal to or greater than 2),
When the electron beam emitted from the multi-lens array is defined as the second electron beam,
The first electron beams irradiated from different positions are incident on the individual lenses of the multi-lens array, thereby forming a maximum of m×n second electron beams,
The control unit
When the direction from the electron source to the multi-lens array is defined as the Z direction, and the emission position when the m first electron beams are emitted is defined as the first electron beam emission position,
The positional relationship between the first electron beam emission position and the lenses included in the multi-lens array when viewed in the Z direction can be controlled so as to be a preset positional relationship.
electron gun. the electron source is a photocathode,
wherein the control unit controls the position of the excitation light received by the photocathode;
An electron gun according to claim 1. the electron source is a field emitter or Schottky,
wherein the controller controls an element that emits the first electron beam from the field emitter or Schottky;
An electron gun according to claim 1. further comprising a rotation mechanism that rotates the multi-lens array with the Z direction as a rotation axis;
wherein the control unit controls the rotation mechanism;
An electron gun according to any one of claims 1-3. further comprising a movement mechanism for moving the multi-lens array in the Z direction as a movement direction;
The control unit controls the movement mechanism,
An electron gun according to any one of claims 1-4. When the arrangement of the first electron beam emission positions is defined as the emission arrangement and the arrangement of the lenses provided in the multi-lens array is defined as the lens arrangement,
the injection arrangement and the lens arrangement are the same or similar arrangements;
When the injection arrangement seen in the Z direction is used as a reference, the lens arrangement seen in the Z direction is rotated about the center of the injection arrangement as a rotation axis so that the arrangement is not the same as or similar to the injection arrangement. placed in the
An electron gun according to any one of claims 1-5. wherein the injection arrangement and the lens arrangement are
3 or more evenly spaced odd points in a straight line,
the four corners and center of the square, and
Six corners and the center of a regular hexagon,
is any one selected from the group consisting of
An electron gun according to claim 6. When the area irradiated with the second electron beam formed on the image plane is defined as the second electron beam irradiation area,
The second electron beam irradiation area has a shape that can fill the irradiation target without loss or overlap.
An electron gun according to claim 7. The injection arrangement and the lens arrangement are four corners and the center of a square, or six corners and the center of a regular hexagon,
the injection arrangement and the lens arrangement satisfy the following equations,
When the injection arrangement seen in the Z direction is used as a reference, the angle of rotation of the lens arrangement seen in the Z direction from the same or similar arrangement as the injection arrangement about the center of the injection arrangement is as follows. represented by θ in the formula of

An electron gun according to claim 8. An electron beam application apparatus comprising the electron gun of claim 9,
The electron beam application device is
scanning electron microscope,
electron beam inspection device, or
scanning transmission electron microscope,
is
Electron beam application equipment. A method of forming a multi-electron beam, the method comprising:
a first electron beam forming step;
a second electron beam forming step;
including
The first electron beam forming step includes:
By forming an electric field between an electron source that generates electrons that can be emitted and an anode, m (m is an arbitrary integer equal to or greater than 2) first electron beams are emitted from the electron source,
or,
An electron beam is extracted by forming an electric field between an electron source that generates electrons that can be emitted and an anode, and m (m is an arbitrary integer of 2 or more) is obtained by dividing the extracted electron beam. 1 forming an electron beam,
The second electron beam forming step includes:
A multi-lens array having n lenses (n is an arbitrary integer equal to or greater than 2) is irradiated with the m first electron beams, and the individual lenses of the multi-lens array are irradiated from different positions. forming a maximum of m×n second electron beams by incidence of the first electron beam,
When the direction from the electron source to the multi-lens array is defined as the Z direction, and the emission position when the first electron beam is emitted from the electron source is defined as the first electron beam emission position,
The positional relationship between the first electron beam emission position and the lenses included in the multi-lens array when viewed in the Z direction is controlled so as to be a preset positional relationship.
A method for forming multiple electron beams. When the arrangement of the first electron beam emission positions is defined as the emission arrangement and the arrangement of the lenses provided in the multi-lens array is defined as the lens arrangement,
the injection arrangement and the lens arrangement are the same or similar arrangements;
When the injection arrangement seen in the Z direction is used as a reference, the lens arrangement seen in the Z direction is rotated about the center of the injection arrangement as a rotation axis so that the arrangement is not the same as or similar to the injection arrangement. placed in the
The method for forming multiple electron beams according to claim 11 . When the irradiation area of the second electron beam formed on the image plane is defined as the second electron beam irradiation area,
The second electron beam irradiation area has a shape that can fill the irradiation target without loss or overlap.
13. The method of forming a multi-electron beam according to claim 12. The injection arrangement and the lens arrangement are four corners and the center of a square, or six corners and the center of a regular hexagon,
the injection arrangement and the lens arrangement satisfy the following equations,
When the injection arrangement seen in the Z direction is used as a reference, the angle of rotation of the lens arrangement seen in the Z direction from the same or similar arrangement as the injection arrangement about the center of the injection arrangement is as follows. represented by θ in the formula of

14. The method of forming a multi-electron beam according to claim 13. A scanning step of scanning a multi-electron beam formed by the multi-electron beam forming method according to claim 14 on an irradiation target,
Scanning method of multiple electron beams.

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