Electron beam generator and additional components

Abstract

The filament (26) is composed of a filament body (46) and filament legs (48, 50). In each filament leg (48, 50), the portion surrounded by the sheath (40, 42) in a non-contact manner is the surrounded portion (64). The ratio of the length (U3, V3) of the surrounded portion (64) to the length (U2, V2) of the stripped portion (63) is 60% or more, preferably 80% or more.

Description

Technical Field

[0001] The present invention relates to an electron beam generating device and additional components, and in particular to a technology for improving the quality of electron beams used for evaporation. Background Art

[0002] The vacuum evaporation device based on the electron beam evaporation method has an electron beam generator (for example, refer to Japanese Patent Publication No. 2004-192903). In such a vacuum evaporation device, the electron beam generated by the electron beam generator is irradiated to the evaporation material in the crucible while being bent by the action of a magnetic field or the like. As a result, the evaporation material evaporates and forms an evaporation film on the surface of the object. The electron beam generator is also called an electron gun or an electron beam gun.

[0003] The electron beam generating device has a filament that emits thermal electrons. The filament generally has a filament body and two filament legs. As the form of the filament body, various forms are known. The entire or most of each filament leg generally has a simple shape, specifically a straight line shape.

[0004] Japanese Patent Application Laid-Open No. 2003-297273 discloses an electron beam generator for vapor deposition. In this electron beam generator, a linear member is wound around the middle of each filament leg. This document does not disclose a member that wraps each filament leg in a non-contact manner.

[0005] In addition, Japanese Patent Gazette No. 2003-317640 discloses an ion source for plasma generation. The ion source is used during ion implantation and is not used during vapor deposition. The ion source has a filament disposed in a plasma generation container. The filament as a whole has a U-shaped form, specifically, it is composed of a middle portion having an arc-shaped form and two linear portions extending from both ends of the middle portion. The vicinity of the root of each linear portion (specifically, the portion where the raw material gas is liquefied if the raw material gas is attached) is wrapped by a sheath. The length of each sheath is very small compared to the length of each linear portion. This can be explained as, in order to increase the amount of arc discharge in the plasma generation container, it is preferred to increase the exposed portion of the filament, and therefore, it is preferred to reduce the length of each sheath while ensuring the function of each sheath as much as possible. Summary of the invention

[0006] The present invention aims to improve the quality of electron beams in an electron beam generator for evaporation. In addition, the present invention aims to increase the temperature of a filament body or make the temperature distribution of the filament body uniform in an electron beam generator for evaporation. In addition, the present invention aims to suppress the release of thermal electrons from outside the filament body. In addition, the present invention aims to extend the life of the filament.

[0007] The electron beam generating device of the present invention is characterized in that it includes: a filament having a filament body, a first filament leg connected to one end of the filament body, and a second filament leg connected to the other end of the filament body; a first holding portion, which holds a first held portion of the first filament leg; a second holding portion, which holds a second held portion of the second filament leg; a first surrounding portion, which surrounds the first surrounded portion of the first filament leg in a non-contact manner, the first surrounded portion being located on the filament body side compared to the first held portion; and a second surrounding portion, which surrounds the second surrounded portion of the second filament leg in a non-contact manner, the second surrounded portion being located on the filament body side compared to the second held portion, in the first filament leg, a first stripped portion is provided between the first held portion and one end of the filament body, in the second filament leg, a second stripped portion is provided between the second held portion and the other end of the filament body, the length of the first surrounded portion is 60% or more relative to the length of the first stripped portion, and the length of the second surrounded portion is 60% or more relative to the length of the second stripped portion.

[0008] The additional component involved in the present invention is characterized in that it includes a surrounding portion, which surrounds the filament pin in the filament that generates the electron beam in a non-contact manner, the surrounding portion has a hollow shape extending in the direction of the central axis of the filament pin, the filament pin is composed of a retained portion and a stripped portion connected to the retained portion, the surrounding portion surrounds the surrounded portion connected to the retained portion within the stripped portion, and the ratio of the length of the surrounded portion to the length of the stripped portion is more than 60%. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a side view showing the electron beam generating device according to the first embodiment.

[0010] Figure 2 is a perspective view showing a first example of a filament assembly.

[0011] Figure 3 is a cross-sectional view showing a first example of a filament assembly.

[0012] Figure 4 It is a side view showing a filament foot and sheath.

[0013] Figure 5 This is a side view showing another filament leg and sheath.

[0014] Figure 6 is a cross-sectional view showing a second example of the filament assembly.

[0015] Figure 7is a cross-sectional view showing a third example of the filament assembly.

[0016] Figure 8 is a cross-sectional view showing a fourth example of the filament assembly.

[0017] Fig. 9 is a cross-sectional view showing a fifth example of the filament assembly.

[0018] Fig.10 It is a diagram showing a first modification example of the filament.

[0019] Fig.11 It is a diagram showing a modified example of the additional components.

[0020] Fig.12 It is a diagram showing a modified example of the structure.

[0021] Fig.13 It is a diagram showing a second modification example of the filament.

[0022] Fig.14 It is a side view showing the electron beam generating device according to the second embodiment.

[0023] Fig.15 is a cross-sectional view of a filament assembly according to a comparative example.

[0024] Fig.16 It is a diagram showing a vapor deposition device. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments will be described with reference to the accompanying drawings.

[0026] (1) Overview of Implementation

[0027] The electron beam generating device for vapor deposition according to the embodiment includes a filament, a first holding portion, a second holding portion, a first surrounding portion, and a second surrounding portion. The filament has a filament body, a first filament leg connected to one end of the filament body, and a second filament leg connected to the other end of the filament body. The first holding portion is a component that holds the first held portion of the first filament leg. The second holding portion is a component that holds the second held portion of the second filament leg. The first surrounding portion is a component that surrounds the first surrounded portion of the first filament leg in a non-contact manner, and the first surrounded portion is located on the filament body side compared to the first held portion. The second surrounding portion is a component that surrounds the second surrounded portion of the second filament leg in a non-contact manner, and the second surrounded portion is located on the filament body side compared to the second held portion. In the first filament leg, the first stripped portion is between the first held portion and one end of the filament body. In the second filament leg, the second stripped portion is between the second held portion and the other end of the filament body. The ratio of the length of the first surrounded portion to the length of the first stripped portion is 60% or more. The ratio of the length of the second surrounded portion to the length of the second peeled portion is 60% or more.

[0028] Hereinafter, depending on the situation, the first filament leg and the second filament leg are sometimes referred to as filament legs, the first held portion and the second held portion are sometimes referred to as held portions, the first surrounded portion and the second surrounded portion are sometimes referred to as surrounded portions, and the first stripped portion and the second stripped portion are sometimes referred to as stripped portions. In addition, the first holding portion and the second holding portion are sometimes referred to as holding portions, and the first surrounding portion and the second surrounding portion are sometimes referred to as surrounding portions.

[0029] According to the above configuration, most (specifically, 60% or more) of the stripped portion of the filament leg is surrounded by the surrounding portion, so that all or part of the plurality of advantages described below can be obtained.

[0030] The radiation energy released from the surrounded portion of the filament pin reaches the surrounding portion, where it is absorbed. In the configuration example described later, heat conduction from the filament pin to the surrounding portion also occurs. Due to radiation (and heat conduction), the temperature of the surrounding portion rises. The surrounded portion of the filament pin is surrounded by the surrounding portion, which is a high-temperature body, in a non-contact manner, so the temperature drop of the filament pin is suppressed, and the heat outflow through the filament pin is suppressed. In other words, the temperature of the filament pin is increased. As a result, the temperature of the filament body is increased, or the temperature distribution of the filament body is uniformized. In particular, the temperature drop near one end and the other end of the filament body can be effectively suppressed. As a result, the amount of thermal electrons released from the filament body can be increased. In other words, the quality of the electron beam is improved (the first advantage).

[0031] For example, when the two filament legs are orthogonal to the thermal electron extraction direction, if two surrounding parts are not provided, the electron beam may be diffused due to the thermal electrons released from the two filament legs. In contrast, if the above structure is adopted, the thermal electrons released from the surrounded portion can be shielded by the surrounding part, so the reduction of the quality of the electron beam can be prevented or suppressed (the second advantage).

[0032] According to the experiment of the inventor, it was confirmed that when the filament is used in an oxygen atmosphere, the life of the filament is extended by adopting the above-mentioned structure. Specifically, when the surrounding part is not used, oxidation is promoted in the middle part of the filament pin, where the diameter is reduced and eventually breaks. In contrast, if the filament pin is surrounded by the surrounding part in a non-contact manner, oxidation can be suppressed (the third advantage). As reasons for this, it can be pointed out that the temperature of the filament pin as a whole rises, the possibility that the intermediate temperature in the filament pin where oxidation is easy to occur is difficult to generate, the possibility that oxygen molecules are difficult to reach the filament pin due to the surrounding part itself, and the possibility that oxygen molecules are difficult to reach the filament pin due to the oxidized particles released into the surrounding part. The possibility of multiple oxidation suppression mechanisms working simultaneously can also be pointed out.

[0033] In addition, the length of the stripped portion is the length along the imaginary central axis of the filament leg, and similarly, the length of the enclosed portion is the length along the imaginary central axis of the filament leg. The length of the enclosed portion is also the length of the enclosing portion. Each length is the length along the component axis. The component axis is the axis passing through the center of gravity of the cross section (cross section) at each position along the length direction of the component.

[0034] When the surrounded portion is not dominant in the stripped portion, specifically, when the ratio of the length of the surrounded portion to the length of the stripped portion is less than 60%, it is not possible to fully suppress the temperature drop of the filament body caused by the heat outflow from the two ends of the filament body, or to generate temperature deviation in the filament body. Therefore, in order to improve the quality of the electron beam, it is necessary to make most or most of the stripped portion as the surrounded portion. Specifically, it is necessary to set the ratio of the length of the surrounded portion to the length of the stripped portion to be 60% or more. In order to further improve the quality of the electron beam, the ratio is preferably 80% or more, particularly preferably 85% or more. The stripped portion may also be completely surrounded by the surrounding portion, that is, the above ratio may also be set to 100%. In order to reliably avoid contact between the filament body and the surrounding portion, the above ratio may also be set to less than 98% or less than 96%.

[0035] In order to make the surrounding part fully function, it is preferred to make the inner surface of the surrounding part close to the outer surface of the surrounded part. In other words, it is preferred to reduce the gap between them. However, the size of the gap should be determined in a way that the surrounded part can reliably avoid contact between the surrounded part and the surrounding part.

[0036] Heat conduction occurs from the held portion of the filament pin to the holding portion. If the held portion is reduced while the filament can be stably and reliably held, the heat flowing from the held portion to the holding portion can be reduced, thereby further suppressing the temperature drop of the entire filament pin. The ratio of the length of the held portion to the overall length of the filament pin can be, for example, less than 20% or less than 30%. In this case, the ratio can also be set to more than 5% or more than 10%. As described above, each length is a length along the central axis.

[0037] In an embodiment, the first enclosing portion has a cylindrical shape that absorbs heat radiated from the first enclosed portion and shields thermal electrons released from the first enclosed portion. The second enclosing portion has a cylindrical shape that absorbs heat radiated from the second enclosed portion and shields thermal electrons released from the second enclosed portion. According to this structure, it is easy to uniformly heat the entire enclosed portion. In addition, the manufacture and installation of each enclosing portion becomes easy.

[0038] The electron beam generating device involved in the embodiment also includes a first clamping mechanism for clamping the first enclosing portion and a second clamping mechanism for clamping the second enclosing portion. If the outer surface of each enclosing portion is a cylindrical surface, it is not necessary to consider its orientation when setting each enclosing portion. The two clamping mechanisms can stably and reliably clamp the two enclosing portions. The two clamping mechanisms can clamp two holding portions in addition to the two enclosing portions. Each clamping mechanism is a structure that functions as a fixing unit or a holding unit.

[0039] In the embodiment, the first holding portion is integrated with the first surrounding portion, and the second holding portion is integrated with the second surrounding portion. That is, the first holding portion and the first surrounding portion are composed of a single component, and the second holding portion and the second surrounding portion are composed of another single component. According to this structure, the installation operation of the first holding portion and the first surrounding portion, and the installation operation of the second holding portion and the second surrounding portion become easy. In addition, it is possible to make the heat conduction from each holding portion to each surrounding portion good.

[0040] In the embodiment, the first additional component is constituted by the first holding portion and the first surrounding portion, and the second additional component is constituted by the second holding portion and the second surrounding portion. The first additional component and the second additional component have the same form as each other. If an additional method is adopted, that is, if the filament and the holding portion and the surrounding portion are respectively monomerized, the additional component can be installed on the filament as needed. If the first additional component and the second additional component have the same form, it is not necessary to consider the type of the additional component when setting the additional component. In addition, when the additional component is consumed, its replacement becomes easy.

[0041] In addition, it is also conceivable to provide the holding portion and the surrounding portion fixedly for each filament leg. For example, the filament may be configured such that the first holding portion, the second holding portion, the first surrounding portion, and the second surrounding portion are integrated or assembled therein.

[0042] In an embodiment, the first retaining portion and the first enclosing portion are a first structure having a first cavity through which the first enclosed portion passes. The first structure absorbs heat released from the first enclosed portion and shields thermal electrons released from the first enclosed portion. The second retaining portion and the second enclosing portion are a second structure having a second cavity through which the second enclosed portion passes. The second structure absorbs heat released from the second enclosed portion and shields thermal electrons released from the second enclosed portion. The first structure and the second structure may each be composed of one or more blocks. The first cavity and the second cavity are respectively wells through which the enclosed portion passes without contact. The bottom wall of the well is equivalent to the retaining portion.

[0043] In an embodiment, the first filament leg has a first straight portion including a first enclosed portion and an inclined portion connected to the first straight portion via a bent portion. The second filament leg has a second straight portion including a second enclosed portion. The first enclosing portion extends to the bent portion or its vicinity. The length of the first enclosing portion is the same as the length of the second enclosing portion. According to this structure, it is easy to avoid contact between the first filament leg (especially its inclined portion) and the first enclosing portion. In addition, the shape of the first enclosing portion and the shape of the second enclosing portion can be made consistent. The inclined portion is a connecting portion between the first straight portion and the filament body.

[0044] The additional component involved in the embodiment includes a surrounding portion, which surrounds the filament pin in the filament that generates the electron beam in a non-contact manner. The surrounding portion has a hollow shape extending in the direction of the central axis of the filament pin. The filament pin is composed of a retained portion and a stripped portion connected to the retained portion. The stripped portion is a portion that is not connected to other components. The surrounding portion surrounds the surrounded portion connected to the retained portion in the stripped portion. The ratio of the length of the surrounded portion to the length of the stripped portion is 60% or more. The additional component is usually configured as a replaceable consumable, but can also be configured as a structure (i.e., a non-consumable) assembled in the electron beam generating device.

[0045] The additional component of the embodiment includes a bottom integrated with the surrounding part. The bottom has a holding hole for inserting the held part. According to this structure, the filament is easily installed. If the surrounding part and the holding part are integrated, their manufacture and handling become easy.

[0046] In any type of filament for vapor deposition, the filament body has a central axis parallel to a direction (first direction) orthogonal to the bundle extraction direction, in other words, the filament body has one end and the other end separated in the first direction. In a filament in which two filament legs extend from both ends of the filament body in a second direction orthogonal to the first direction, the filament body has a complex form such as a spiral form, a linear form, a curved form, etc. In this case, the filament body has a fixed width in the second direction, and two portions exceeding the width are defined as two filament legs. In a filament in which two filament bodies extend from both ends of the filament body in parallel to the first direction, the filament body has a non-linear form such as a spiral form and a plate form. In this case, the two portions exceeding the two ends of the portion having a non-linear shape can be defined as two filament legs. In the case where two portions having an L-shape are drawn out from both ends of the portion having a non-linear form, the non-linear portion is defined as the filament body, and the two portions drawn out therefrom are defined as two filament legs.

[0047] (2) Details of implementation methods

[0048] Figure 1 The electron beam generator 10 for evaporation according to the first embodiment is shown. The electron beam generator 10 is arranged in a vacuum chamber of a vacuum evaporation device. The electron beam generated by the electron beam generator 10 is irradiated to the evaporation material in the crucible. When a metal oxide film such as a silicon dioxide (SiO2) film, a zirconium oxide (ZrO2) film, a titanium oxide (TiO2) film, etc. is formed on the surface of an object as a evaporation film, oxygen is introduced into the vacuum chamber. However, the structure described below can also function effectively without introducing oxygen into the vacuum chamber.

[0049] In addition, Figure 1 In the following description, for example, the x direction is the first horizontal direction, the y direction is the second horizontal direction, and the z direction is the vertical direction (plumb direction).

[0050] The member 12 is made of a conductive member such as copper, and an anode electrode 30 as an extraction electrode is fixed to the member 12. The base 16 is connected to the member 12 via the insulating member 14. The insulating member 14 is, for example, an insulator. The base 16 is made of, for example, stainless steel.

[0051] As will be described later, the base set 18 is composed of a pair of bases, which are fixed to the base 16. The pair of bases are physically and electrically separated from each other. The base 16 may also be composed of a pair of base members.

[0052] Four blocks 22R, 24R, 22L, and 24L are mounted on the base assembly 18. They include two block pairs arranged in the x direction. Each block pair is composed of two blocks arranged in the y direction. Each block 22R, 24R, 22L, and 24L is composed of conductive components such as stainless steel and copper.

[0053] The filament 26 is made of, for example, tungsten. The filament 26 is a component that releases thermal electrons by generating heat. As described later, the filament 26 is composed of a filament body and two filament legs (a first filament leg and a second filament leg). When a filament current flows through the filament 26, the filament 26 generates heat and reaches a very high temperature, and thermal electrons are released from the filament 26. When the filament 26 is consumed, it is replaced with a new one.

[0054] In an embodiment, two filament legs of the filament 26 are surrounded by two sheaths 40, 42. Each sheath 40, 42 is made of, for example, a heat-resistant metal or ceramic, and in an embodiment, is made of stainless steel. Each sheath 40, 42 limits the heat outflow from the filament body by surrounding each filament leg, thereby increasing the temperature of the filament body or making the temperature distribution of the filament body uniform. Depending on the setting method and use environment of the filament 26, in addition to the above-mentioned basic advantages, each sheath 40, 42 also provides a plurality of secondary advantages described later. The structure and function of each sheath 40, 42 will be described in detail later.

[0055] The filament assembly 300 according to the first example includes a filament 26, a pair of sheaths 40, 42, a base assembly 18, and a plurality of blocks 22R, 24R, 22L, 24L. The two right blocks 22R, 24R and the two left blocks 22L, 24L each function as a clamping mechanism. The two sheaths 40, 42 are clamped by the two clamping mechanisms to hold the filament 26. In addition, a beam shaping electrode 32 is provided so as to cover the filament body of the filament 26.

[0056] A fixed voltage is applied between the two filament legs by the power supply 36, and a filament current flows through the filament 26. As a result, the filament 26 generates heat, and thermal electrons are released from the filament 26. On the other hand, the anode electrode 30 is grounded. A negative voltage in the range of, for example, -4 to -12 kV is applied to the filament 26 by the power supply 34. This negative voltage acts as an extraction voltage for accelerating thermal electrons released from the filament 26 in a predetermined direction. As a result, an electron beam 38 is generated.

[0057] The beam extraction direction is the -y direction. In the first embodiment, each filament leg is orthogonal to the beam extraction direction. Fig.14 In the second embodiment shown, the filament legs are parallel to the bundle extraction direction.

[0058] In order to manipulate the electric field near the filament 26 to generate a good electron beam 38, a beam shaping electrode 32 is provided. The arrangement and form of the filament 26, the anode electrode 30, the beam shaping electrode 32, etc. are only exemplified. In addition, the electron beam 38 is deflected by the magnetic field formed by the permanent magnet or electromagnet not shown, and irradiated to the evaporation material in the crucible.

[0059] Fig.16 2 shows a vacuum evaporation device 200 based on electron beam evaporation method. The interior of the vacuum container is a vacuum chamber 201, and an electron beam generator 202, a crucible 204, a holder 208, etc. are arranged in the vacuum chamber 201. A evaporation material 206 is placed in the crucible 204. The dome-shaped holder 208 holds a plurality of objects (processed products) 210. An electron beam 212 is generated in the electron beam generator 202 and irradiated to the evaporation material 206. As a result, the evaporation material 206 evaporates (see reference numeral 214). As a result, a vapor deposition layer is formed on the surface of the plurality of objects 210.

[0060] A turntable for holding a plurality of crucibles may also be arranged in the vacuum chamber 201. In this case, the evaporation material to be irradiated with the electron beam is selected by changing the rotation angle of the turntable. In order to effectively or stably form a good evaporation layer, it is desirable that the quality of the electron beam 212 (particularly the electron beam morphology and the thermal electron density) is good.

[0061] exist Figure 2 , a perspective view of a filament assembly 300 according to the first example is shown. The two filament legs of the filament 26 are surrounded by two sheaths 40, 42. The base group 18 is composed of two bases 18R, 18L arranged in the x direction.

[0062] Bolts are provided across the two blocks 22R and 24R arranged in the y direction to fasten them, but the illustration is omitted. The two blocks 22R and 24R and the bolts fastening them constitute the clamping mechanism 320. Bolts are provided across the two blocks 22L and 24L arranged in the y direction to fasten them, but the illustration is omitted. The two blocks 22L and 24L and the bolts fastening them constitute the clamping mechanism 322.

[0063] The clamping mechanism 320 is a mechanism for clamping the sheath 40, and the clamping mechanism 322 is a mechanism for clamping the sheath 42. V-shaped grooves 44 for clamping are formed on the blocks 22R, 24R, 22L, and 24L, respectively. The sheaths 40 and 42 can be held by other mechanisms or other structures. Incidentally, the two clamping mechanisms 320 and 322 are electrically insulated from each other.

[0064] Figure 3A front view of a filament assembly 300 according to the first example is shown. The filament 26 is composed of a filament body 46 and two filament legs 48 and 50. The filament 26 is made, for example, by forming a linear member having a predetermined diameter. That is, in the embodiment, the filament body 46, the filament legs 48 and the filament legs 50 have a uniform cross-sectional shape (circular) and a uniform cross-sectional size, respectively, except for some curved portions generated when the filament is formed. However, the cross-sectional shape and cross-sectional size of the filament body 46 may be different from the cross-sectional shape and cross-sectional size of the filament legs 48 and 50. The filament legs 48 are led out from one end of the filament body 46, and the filament legs 50 are led out from the other end of the filament body 46.

[0065] The filament body 46 is in a solenoid shape, that is, in a coil shape or a spiral shape, and its central axis 68 is parallel to the x direction. The central axis 68 is orthogonal to the beam extraction direction. The number of turns of the filament body 46 is, for example, in the range of 5 to 10. Other filament bodies other than the solenoid shape may also be used. For example, a linear filament body, a spiral filament body, a plate-shaped filament body, etc. may be used.

[0066] The length 46A of the filament body 46 in the x direction is set within a range of 9 to 20 mm, for example. The length 46A may be 12 mm. The height of the entire filament 26 (dimension in the z direction) is set within a range of 14 to 30 mm, for example. For example, the height may be 17 mm.

[0067] One end (right end) of the filament body 46 is connected to the filament pin 48. The other end (left end) of the filament body 46 is connected to the filament pin 50. In the illustrated configuration example, the two filament pins 48 and 50 extend in a direction (i.e., z direction) orthogonal to the central axis 68 of the filament body 46. One end and the other end of the filament body 46 are separated in the x direction.

[0068] The filament body 46 has a fixed extension in the z direction. The height of its lower edge is represented by z1. In the filament 26 shown in the figure, the portion below the height z1 is defined as filament legs 48, 50. In the case where the filament body has a simple straight-line shape or a spiral-shaped shape, the two filament legs can be defined based on the filament body as described above.

[0069] In the illustrated configuration example, the filament pin 48 and the filament pin 50 have the same configuration except for a portion. First, the filament pin 48 will be described in detail.

[0070] The filament pin 48 is roughly divided into a held portion 62 and a stripped portion 63 connected to the held portion. The held portion 62 is a portion held by the sheath 40. The stripped portion 63 is a portion that does not contact other components. The stripped portion 63 is composed of a surrounded portion 64 and an exposed portion 65 connected to the portion. The surrounded portion 64 is an intermediate portion surrounded by the sheath 40 in a non-contact manner, in other words, a portion that is lower than the opening of the sheath 40 and higher than the bottom 54 described later. The exposed portion 65 is a portion that is pushed out of the sheath 40. The surrounded portion 64 and the non-held portion constitute a straight portion.

[0071] In the filament leg 48, the exposed portion 65 is an inclined portion (see reference numeral 65A). In this respect, the filament leg 48 is different from the filament leg 50. In the filament leg 50, the exposed portion 65 is a straight portion (see reference numeral 65B).

[0072] The filament pin 48 has a central axis U as a virtual axis. The central axis U is a component axis passing through the center of gravity of the cross section at each position of the filament pin 48. As the length along the central axis U, the total length of the filament pin 48 is represented by U1, the length of the stripped portion 63 is represented by U2, the length of the surrounded portion 64 is represented by U3, and the length of the exposed portion 65 is represented by U4. U3 is also the length of the cylindrical portion (surrounding portion) 52 described later.

[0073] In the embodiment, in order to improve the quality of the electron beam, the majority or most of the stripped portion 63, specifically, more than 60% thereof, is set as the surrounded portion 64. In detail, the ratio of the length U3 of the surrounded portion 64 to the length U2 of the stripped portion 63 is set to more than 60%. In order to further improve the quality of the electron beam, the ratio of the length U3 of the surrounded portion 64 to the length U2 of the stripped portion 63 is set to more than 80%, and more preferably, to more than 85%.

[0074] In order to satisfy the above numerical conditions, the shape of the sheath 40 is specified. The entire stripped portion 63 may also be the surrounded portion 64. In other words, the above ratio may be 100%. However, in order to avoid contact between the sheath 40 and the filament body 46, the above ratio is preferably 98% or less or 96% or less.

[0075] As described above, the filament pin 50 has the same shape as the filament pin 48 except for a part. In detail, the filament pin 50 is defined as the part below z1, and is linear as a whole. The filament pin 50 is roughly divided into a held portion 62 and a stripped portion 63, and the stripped portion 63 is composed of a surrounded portion 64 and an exposed portion 65. The exposed portion 65 of the filament pin 50 is parallel to the z direction (see the reference numeral 65B). In this respect, the shape of the filament pin 50 is different from that of the filament pin 48.

[0076] The filament pin 50 has a central axis V as a virtual axis. The central axis V is equivalent to the component axis as described above. The length of each part is defined along the central axis V. The entire length of the filament pin 50 is represented by V1. In the filament pin 50, the length of the stripped portion 63 is represented by V2, the length of the surrounded portion 64 is represented by V3, and the length of the exposed portion 65 is represented by V4.

[0077] In the embodiment, from the viewpoint of improving the quality of the electron beam, the same numerical conditions as the above numerical conditions are also applied to the filament pin 50. That is, the ratio of the length U3 of the surrounded portion 64 to the length U2 of the stripped portion 63 is set to 60% or more. In order to further improve the quality of the electron beam, the ratio of the length U3 of the surrounded portion 64 to the length U2 of the stripped portion 63 is set to 80% or more, and particularly preferably to 85% or more. In order to satisfy the above numerical conditions, the form of the sheath 42 is specified.

[0078] In order to suppress the outflow of heat through the held portion 62, the ratio of the length of the held portion 62 to the total length of the filament legs 48, 50 may be set to 30% or 20% or less. In this case, the lower limit of the ratio may be 5% or 10% or more.

[0079] Next, the sheath 40 and the sheath 42 are described in detail. The sheath 40 and the sheath 42 have the same structure as each other. The sheath 42 is used as a representative for description.

[0080] The sheath 42 is an additional component. The sheath 42 has a cylindrical shape as a whole. The sheath 42 is made of a material that can withstand high temperatures, such as metal, ceramic, etc. Specifically, the sheath 42 is made of stainless steel. The sheath 42 can be made of tungsten. The outer surface of the sheath 42 is a cylindrical surface.

[0081] The sheath 42 is composed of a cylindrical portion 52 and a bottom portion 54. In practice, the sheath 42 is composed of a single member, that is, the cylindrical portion 52 and the bottom portion 54 are integrated. Alternatively, the cylindrical portion 52 and the bottom portion 54 may be separately formed into individual parts and then combined.

[0082] The cylindrical portion 52 functions as a surrounding portion. The cylindrical portion 52 surrounds the surrounded portion 64 of the filament pin 50 in a non-contact manner. In the illustrated configuration example, the surrounded portion 64 may also be referred to as an intermediate portion. Both the outer surface and the inner surface of the cylindrical portion 52 are cylindrical surfaces. The inner surface of the cylindrical portion 52 faces the internal space 58.

[0083] The wall thickness of the cylindrical portion 52 is set, for example, within the range of 0.1 to 4 mm, and is 0.3 mm in the illustrated configuration example. The inner diameter of the cylindrical portion is set, for example, within the range of 1 to 4 mm, and is 1.5 mm in the illustrated configuration example. The outer diameter of the cylindrical portion is set, for example, within the range of 2 to 12 mm, and is 2.1 mm in the illustrated configuration example. The distance between the surface of the filament pin 50 and the inner surface of the cylindrical portion 52 (see reference numeral 70) is set, for example, within the range of 0.1 to 1.6 mm, and is 0.35 mm in the illustrated configuration example. The length of the stripped portion 63 is set, for example, within the range of 10 to 30 mm, and the length of the surrounded portion 64 is set, for example, within the range of 6 to 30 mm. In any case, each length is specified so as to satisfy the above-mentioned numerical conditions. In addition, the width of the exposed portion 65 in the z direction, that is, the gap between the filament body 46 and the sheaths 40 and 42, is set, for example, within the range of 0.5 to 2.5 mm.

[0084] The bottom 54 is the bottom wall of the sheath 42, and functions as a holding portion. The bottom 54 has a disc-like shape, and a holding hole 60 is formed in the center thereof. A non-holding portion (lower end portion) 62 of the filament pin 50 is detachably inserted into the holding hole 60, and the held portion 62 is held by the bottom 54. The held portion 62 and the inner surface of the holding hole 60 may also be fixed. The filament 26 and the sheath 42 (and the sheath 40) may be integrated.

[0085] In the filament pin 50, the portion accommodated in the internal space 58 of the cylindrical portion 52 is the surrounded portion 64. The cylindrical portion 52 has an embedded portion 56 existing below the upper surface of the block 24L and a protruding portion 55 protruding above the upper surface of the block 24L. In the illustrated configuration example, the protruding portion 55 extends to the vicinity of the filament body 46. Thus, the above-mentioned numerical conditions are satisfied.

[0086] The shape of the sheath 42 is defined so that the sheath 42 does not contact the filament 26 except for the bottom 54. From the viewpoint of increasing the temperature of the filament body 46 or making the temperature distribution uniform, it is preferable to increase the ratio of the length U3, V3 of the surrounded portion to the length U2, V2 of the stripped portion 63, but from the viewpoint of reliably preventing the sheaths 40, 42 from contacting the filament 26, it is preferable to make the above ratio less than 100%.

[0087] In addition, in order to suppress the flow of the sheaths 40 and 42 to the blocks 24R and 24L (and Figure 2 The heat outflow of the blocks 22R, 22L, etc. shown in the figure can also be reduced by thinning the thickness of each block in the z direction.

[0088] As described above, the sheath 40 has the same structure as the sheath 42. A plurality of sheaths having the same form may be produced, and any two of them may be used as the sheath 40 and the sheath 42. Each of the sheaths 40 and 42 is held by four V-groove inner surfaces 44A.

[0089] Figure 4 1 is a right side view showing a filament leg 48 of the filament 26. The filament body 46 has a spiral shape, and its outer shape is close to a cylinder. The filament leg 48 includes a straight portion 48a and an inclined portion 48b. The straight portion 48a and the inclined portion 48b are connected via a curved portion 48c. The straight portion 48a corresponds to the surrounded portion 64 and the retained portion. The inclined portion 48b is an exposed portion 65 (65A). The inclined portion 48b is a connecting portion that connects the straight portion 48a to the filament body 46.

[0090] The length U2 of the stripped portion 63 corresponds to the sum of the length U3 of the surrounded portion 64 and the length U4 of the inclined portion 48b (exposed portion 65). The upper end height of the sheath 40 is located at or near the curved portion 48c. Figure 4 4 shows thermal electrons R emitted from the surrounded portion 64. The thermal electrons R are shielded by the inner surface of the sheath 40. Thus, degradation of the quality of the electron beam due to the thermal electrons R is prevented.

[0091] Figure 5 FIG. 2 is a right side view showing the other filament leg 50 of the filament 26. Figure 5 In the figure, the same reference numerals are given to the elements already described. The filament pin 50 is in a straight line shape as a whole. The filament pin 50 has a stripped portion 63, which is composed of a surrounded portion 64 and an exposed portion 65. The ratio of the length V3 of the surrounded portion 64 to the length V2 of the stripped portion 63 satisfies the above-mentioned numerical conditions. In the filament pin 50, the thermal electrons R emitted from the surrounded portion 64 are also shielded by the sheath 42, preventing the degradation of the quality of the electron beam caused by the thermal electrons R.

[0092] In the structure involved in the above-mentioned embodiment, the radiation energy emitted from each surrounded part of each filament leg reaches the inner surface of each sheath. In addition, heat is supplied from each filament leg to each sheath through heat conduction. As a result, the temperature of each sheath rises. At the same time, the temperature of each filament leg rises, and the heat outflow through each filament leg is suppressed. As a result, the temperature of the filament body is increased, or the temperature distribution here is uniform. As a result, the quality of the electron beam is improved.

[0093] In the filament assembly according to the first example, since the cylindrical portion and the bottom portion are formed as one body in each sheath, heat conduction from the bottom portion to the cylindrical portion is promoted. In addition, the filament is detachably held by two holding holes formed in the two bottom portions, and a complicated structure does not need to be provided when holding the filament. In addition, the central axis of each filament leg coincides with the central axis of each cylindrical portion.

[0094] Figure 6 A filament assembly 302 is shown in accordance with a second example. Figure 6 : shows a horizontal cross section of the filament assembly 302. A well 72A is formed in the block 72 and a well 74A is formed in the block 74. A sheath 76 is partially inserted in the well 72A and a sheath 78 is partially inserted in the well 74A. The sheath 76 and the sheath 78 are respectively enclosed by the filament legs 49R and 49L. In this way, the sheaths 76 and 78 may be prismatic.

[0095] Figure 7 The filament assembly 304 according to the third example is shown. A block 82 is mounted on a base 80, and a block 84 is mounted on a base 81. A through hole is formed in the block 82, and a cylindrical sheath 86 is inserted into the through hole. Similarly, a through hole is formed in the block 84, and a cylindrical sheath 88 is inserted into the through hole. The lower end surfaces of the sheaths 86 and 88 abut against the upper surfaces of the bases 80 and 81. The filament 90 has filament pins 92 and 94. The base 80 has a holding hole 96 for holding a held portion (end portion) 92A of the filament pin 92. The base 81 has a holding hole 98 for holding a held portion (end portion) 94A of the filament pin 94. The end surfaces of the held portions 92A and 94A abut against the bottom surfaces of the holding holes 96 and 98.

[0096] Each sheath 86, 88 is configured to satisfy the above numerical conditions. That is, in each filament leg 92, 94, the ratio of the length U3, V3 of the surrounded portion 64 to the length U2, V2 of the stripped portion 63 is 60% or more, preferably 80% or more.

[0097] Figure 8 The filament assembly 306 according to the fourth example is shown. The filament 110 has filament pins 112 and 114. The block 102 is mounted on the base 100, and the block 104 is mounted on the base 101. The block 102 is formed with a well 106, and the block 104 is formed with a well 108. A through hole is formed at the bottom 102B of the well 106, and a held portion (end portion) 112A of the filament pin 112 is inserted into the through hole. A through hole is formed at the bottom 104B of the well 108, and a held portion (end portion) 114A of the filament pin 114 is inserted into the through hole. Each through hole functions as a holding hole.

[0098] In the blocks 102 and 104, the portions 102A and 104A surrounding the wells 106 and 108 respectively function as surrounding portions. The bottom portions 102B and 104B in the blocks 102 and 104 function as retaining portions. The portions 102A and 104A surrounding the wells 106 and 108 become high temperature portions, resulting in an increase in the temperature of the filament pins 112 and 114 and suppression of heat outflow therefrom. The wells 106 and 108 have two cavities 106A and 108A formed inside, and the surrounded portions of the two filament pins 112 and 114 pass through these cavities 106A and 108A.

[0099] In the structure according to the fourth example, as described above, the blocks 102 and 104 as the structure function as the surrounding portion and the holding portion. In addition, the blocks 102 and 104 can function as the clamping member.

[0100] Each block 102, 104 is configured to satisfy the above numerical conditions. That is, in each filament leg 112, 114, the ratio of the length U3, V3 of the surrounded portion 64 to the length U2, V2 of the stripped portion 63 is 60% or more, preferably 80% or more.

[0101] Fig. 9 The filament assembly 308 according to the fifth example is shown. The filament 120 has a filament body 122 and filament legs 124 and 126. The filament legs 124 and 126 extend from both ends of the filament body 122 to both sides of the filament body 122. Specifically, the central axis of each filament leg 124 and 126 is parallel to the central axis of the filament body 122.

[0102] The sheaths 128 and 130 are respectively composed of cylindrical parts 136 and 140 and bottoms 138 and 142. The held portions (ends) 124A and 126A of the filament pins 124 and 126 are held by the bottoms 138 and 142 as the holding portions. The surrounded portions of the filament pins 124 and 126 pass through the inside of the cylindrical parts 136 and 140. The sheaths 128 and 130 are held by the blocks 132 and 134.

[0103] In the structure of the fifth example, each sheath 128, 130 is also configured to satisfy the above numerical conditions. That is, in each filament leg 124, 126, the ratio of the length U3, V3 of the surrounded portion to the length U2, V2 of the stripped portion is 60% or more, preferably 80% or more. In addition, the complex portion (helical portion) with an increased surface area is the filament body 122, and the two straight portions drawn from both ends thereof are the two filament legs 124, 126.

[0104] Fig.10 The first modification of the filament is shown. In addition, the same reference numerals are given to the elements already described and their description is omitted. Fig.11The same is true.

[0105] exist Fig.10 In the embodiment, the ends of the two filament legs in the filament 26A have an L-shaped form. Specifically, the ends of the filament legs 150 pass through the retaining hole 60 formed in the bottom 54 of the sheath 40. The ends are composed of a first portion 150d connected to the surrounded portion and a second portion 150e connected to the first portion 150d. The first portion 150d is parallel to the z direction, and the second portion is parallel to the y direction. There is a bend between them. Fig.10 In the structure shown, the first portion 150d is the portion to be held. Alternatively, the entire end portion may be the portion to be held.

[0106] In addition, the entire filament leg may be formed into an L-shape. In this case, the end portion may also be formed into an L-shape in the same manner as described above.

[0107] Fig.11 1 shows a modified example of the sheath (additional component). The sheath 152 divided into two parts is composed of a first part 152a and a second part 152b. A groove 154a is formed at the bottom of the first part 152a, and a groove 154b is formed at the bottom of the second part 152b. The sheath 152 is formed by the combination of the first part 152a and the second part 152b. In this case, the held portion of the filament pin 150 is held by the two grooves 154a and 154b. The two grooves 154a and 154b function as a holding hole 154 in their combined state.

[0108] Fig.12 A modified example of a structure for holding a filament is shown. The filament leg 150 of the filament 26A is held by the combination of the block 156 and the block 158. The other filament leg is also held by the same structure.

[0109] Block 156 has a semi-cylindrical recess 160A and a groove 164A. Block 158 also has a semi-cylindrical recess 160B and a groove 164B. The combination of blocks 156 and 158 holds the filament pin 150.

[0110] Specifically, in the combined state, the two grooves 164A and 164B are combined to function as a holding hole, and the held portion of the filament pin 150 is held by the two grooves 164A and 164B. In the combined state, the two recesses 160A and 160B are combined to form a cavity 160 that accommodates the surrounded portion of the filament pin 150. The periphery of the cavity 160 functions as a surrounding portion. The lower side portion of the cavity 160 functions as a holding portion.

[0111] Fig.13Indicates a modification of the filament. The illustrated filament 166 has a linear filament body 168 and two filament legs 170, 172 extending from both ends thereof. The filament body 168 extends in the x-direction, and each filament leg 170, 172 extends in the z-direction. The cross-section of the filament body 168 is, for example, semicircular, D-shaped, flat, or the like. In this modification, the main portion that releases thermal electrons is the portion parallel to the x-direction, which is the filament body 168. That is, in the z-direction, the range indicated by the figure numeral 174 corresponds to the filament body 168. The portion below, specifically, the two portions within the range indicated by the figure numeral 175 are the filament legs 170, 172. Two sheaths are mounted on the two filament legs 170, 172.

[0112] Fig.14 The electron beam generating device for vapor deposition according to the second embodiment is shown. In the first embodiment, a filament having a vertical posture is provided in the electron beam generating device, but in the second embodiment, a filament 26 having a horizontal posture is provided in the electron beam generating device. The clamping mechanism 184 holds two sheaths 40 and 42 having a horizontal posture. The enclosed portions of the two filament legs are enclosed by the two sheaths 40 and 42, and the held portions of the two filament legs are held. Reference numeral 30 indicates an anode electrode for thermal electron extraction, and reference numeral 186 indicates a beam shaping electrode. The beam extraction direction is the -y direction. Reference numeral 38 indicates an electron beam.

[0113] In the second embodiment, the sheaths 40 and 42 are also provided so as to satisfy the above numerical conditions. This can increase the temperature of the filament body or make its temperature distribution uniform, thereby improving the quality of the electron beam.

[0114] Fig.15 The filament 220 is made of tungsten and is disposed in a vacuum chamber. Oxygen is introduced into the vacuum chamber. That is, the filament 220 is in an oxygen atmosphere.

[0115] The filament 220 is composed of a filament body 222 and two filament legs 224 and 226. The filament legs 224 are clamped by the right side block pair ( Fig.16 Only one block 228 is shown in the right pair of blocks, and the filament foot 226 is clamped by the left pair of blocks ( Fig.16 Only one block 230 is shown in the middle left block pair. The filament body 222 is the high temperature part. A temperature gradient is generated in the stripped parts of each filament leg 224, 226. In particular, an intermediate temperature that is easy to oxidize is generated in the middle parts 232, 234 in each stripped part. The melting point of tungsten oxide is lower than that of tungsten, and the oxidized part evaporates, which promotes the thinning of the middle parts 232, 234. When oxidation further proceeds, the middle parts 232, 234 break.

[0116] According to the structure involved in the embodiment, the stripped portion of each filament leg is surrounded by the surrounding portion, thereby increasing the overall temperature of each filament leg. As a result, the generation of the above-mentioned intermediate temperature can be effectively avoided. In other words, the life of the filament can be extended. According to experiments, it has been confirmed that the life of the filament can be increased by 3 times.

[0117] According to the structure involved in the embodiment, the quality of the electron beam can be improved. The advantage is that it can be obtained regardless of whether there is oxygen in the vacuum chamber. In particular, the advantages of high temperature or uniform temperature distribution of the filament body can be obtained in the structure of the first embodiment and the structure of the second embodiment. The structure involved in the embodiment can also be applied to other electron beam generating devices.

Claims

1. An electron beam generating device for evaporation, It is characterized in that The invention comprises: a filament having a filament body, a first filament leg connected to one end of the filament body, and a second filament leg connected to the other end of the filament body; a first holding portion that holds a first held portion of the first filament leg; a second holding portion that holds a second held portion of the second filament leg; a first surrounding portion surrounding a first surrounded portion of the first filament leg in a non-contact manner, the first surrounded portion being located on the filament body side relative to the first held portion; and a second surrounding portion surrounding a second surrounded portion of the second filament leg in a non-contact manner, the second surrounded portion being located on the filament body side relative to the second held portion, In the first filament leg, a first stripping portion is formed between the first held portion and one end of the filament body. In the second filament leg, a second stripping portion is formed between the second held portion and the other end of the filament body. The ratio of the length of the first surrounded portion to the length of the first peeled portion is 60% or more, The ratio of the length of the second surrounded portion to the length of the second peeled portion is 60% or more, The first surrounding portion has a form that absorbs heat radiated from the first surrounded portion and shields thermal electrons released from the first surrounded portion, The second surrounding portion has a form that absorbs heat radiated from the second surrounded portion and shields thermal electrons released from the second surrounded portion.

2. The electron beam generating device for vapor deposition according to claim 1, characterized in that: The ratio of the length of the first surrounded portion to the length of the first peeled portion is 80% or more, The ratio of the length of the second surrounded portion to the length of the second peeled portion is 80% or more.

3. The electron beam generating device for vapor deposition according to claim 1, characterized in that: The first surrounding portion has a cylindrical shape that absorbs heat radiated from the first surrounded portion and shields thermal electrons released from the first surrounded portion. The second surrounding portion has a cylindrical shape that absorbs heat radiated from the second surrounded portion and shields thermal electrons released from the second surrounded portion.

4. The electron beam generating device for vapor deposition according to claim 3, characterized in that: include: A first clamping mechanism for clamping the first surrounding portion; and A second clamping mechanism clamps the second surrounding portion.

5. The electron beam generating device for vapor deposition according to claim 1, characterized in that: The first holding portion is integrated with the first surrounding portion, The second holding portion is integrated with the second surrounding portion.

6. The electron beam generating device for vapor deposition according to claim 5, characterized in that: The first retaining portion and the first surrounding portion constitute a first additional component, The second retaining portion and the second surrounding portion constitute a second additional component, The first additional component and the second additional component have the same form as each other.

7. The electron beam generating device for vapor deposition according to claim 1, characterized in that: The first holding portion and the first surrounding portion are first structures having a first hole through which the first surrounded portion passes. The first structure absorbs heat released from the first surrounded portion and shields thermal electrons released from the first surrounded portion. The second holding portion and the second surrounding portion are second structures having a second hole through which the second surrounded portion passes. The second structure absorbs heat released from the second surrounded portion and shields thermal electrons released from the second surrounded portion.

8. The electron beam generating device for vapor deposition according to claim 1, characterized in that: The first filament leg includes a first straight portion including the first surrounded portion, and an inclined portion connected to the first straight portion via a bent portion. The second filament leg has a second straight portion including the second surrounded portion, The first surrounding portion extends to the bent portion or its vicinity, The length of the first surrounding portion is the same as the length of the second surrounding portion.

9. An additional component for an electron beam generating device, characterized in that: The invention comprises a surrounding portion which surrounds the filament leg in the filament for generating the electron beam in a non-contact manner, The surrounding portion has a hollow shape extending toward the central axis of the filament leg. The filament foot is composed of a held portion and a stripped portion connected to the held portion. The surrounding portion surrounds the surrounded portion connected to the held portion in the stripped portion, The ratio of the length of the surrounded portion to the length of the stripped portion is 60% or more, The surrounding portion has a form that absorbs heat radiated from the surrounded portion and shields thermal electrons released from the surrounded portion.

10. The additional component according to claim 9, characterized in that comprising a bottom portion integrated with the surrounding portion, The bottom portion has a holding hole into which the held portion is inserted.

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