JP2021132025A - Electron beam generation device and attachment member - Google Patents

Abstract

To improve the quality of an electron beam in an electron beam generation device for vapor deposition.SOLUTION: A filament 26 includes a filament body 46 and filament legs 48 and 50. In each of the filament legs 48 and 50, a portion surrounded by sheaths 40 and 42 in a non-contact manner is an enclosed portion 64. The ratio of the lengths U3 and V3 of the enclosed portion 64 to the lengths U2 and V2 of an exposed portion 63 is 60% or more, and preferably 80% or more.SELECTED DRAWING: Figure 3

Description

The present invention relates to an electron beam generator and an attachment member, and more particularly to a technique for improving the quality of an electron beam for vapor deposition.

The vacuum vapor deposition apparatus based on the electron beam deposition method includes an electron beam generator (see, for example, Patent Document 1). In such a vacuum vapor deposition apparatus, the electron beam generated by the electron beam generator is irradiated to the vapor deposition material in the crucible while being bent by the action of a magnetic field or the like. As a result, the vaporized material evaporates, and a thin-film film is formed on the surface of the object. The electron beam generator is also called an electron gun or an electron beam gun.

The electron beam generator has a filament that emits thermions. The filament generally has a filament body and two filament legs. Various forms of the filament body are known. All or most of each filament leg usually has a simple morphology, specifically a linear morphology.

Patent Document 2 discloses an electron beam generator for vapor deposition. In the electron beam generator, a linear member is wound around an intermediate portion of each filament leg. Patent Document 2 does not disclose a member that wraps each filament leg in a non-contact manner.

In addition, Patent Document 3 discloses an ion source for plasma generation. The ion source is used in ion implantation, not in vapor deposition. The ion source has filaments arranged in a plasma generating vessel. The filament has a U-shaped shape as a whole, and specifically, it is composed of an intermediate portion having an arc-shaped shape and two linear portions extending from both ends of the intermediate portion. The vicinity of the root of each linear portion (specifically, the portion where the raw material gas is liquefied when the raw material gas adheres) is surrounded by a sheath. The length of each sheath is considerably smaller than the length of each linear part. In order to increase the amount of arc discharge in the plasma generation vessel, it is better to increase the exposed part of the filament, and therefore it is better to reduce the length of each sheath as long as the function of each sheath can be ensured. It is understood as a good one.

Japanese Unexamined Patent Publication No. 2004-192903 Japanese Unexamined Patent Publication No. 2003-297273 Japanese Unexamined Patent Publication No. 2003-317640

An object of the present invention is to improve the quality of an electron beam in an electron beam generator for vapor deposition. Alternatively, an object of the present invention is to make the temperature of the filament body higher or to make the temperature distribution of the filament body uniform in the electron beam generator for vapor deposition. Alternatively, an object of the present invention is to suppress the emission of thermoelectrons from other than the filament body. Alternatively, an object of the present invention is to extend the life of the filament.

The electron beam generator according to the present invention comprises a filament body, a filament having a first filament leg connected to one end of the filament body, a second filament leg connected to the other end of the filament body, and the first filament leg. The first holding portion that holds the first held portion, the second holding portion that holds the second held portion portion of the second filament leg, and the first filament leg that is more than the first held portion. A first enclosing portion that non-contactly encloses the first enclosing portion existing on the filament body side, and a second enclosing portion existing on the filament body side of the second filament leg with respect to the second held portion. A second enclosing portion that surrounds the filament in a non-contact manner is included, and a first exposed portion is provided between the first held portion and one end of the filament body in the first filament leg, and the second filament leg is said to have the same. The second exposed portion is between the second held portion and the other end of the filament body, and the ratio of the length of the first enclosed portion to the length of the first exposed portion is 60% or more. The ratio of the length of the second enclosed portion to the length of the second exposed portion is 60% or more.

The attachment member according to the present invention includes an enclosing portion that non-contactly encloses the filament legs in the filament that generates an electron beam, and the enclosing portion has a hollow form extending in the axial center direction of the filament legs, and the filament. The leg is composed of a held portion and an exposed portion connected to the held portion, and the surrounding portion surrounds the enclosed portion connected to the held portion within the exposed portion, and the enclosed portion relative to the length of the exposed portion. The proportion of the length of the portion is 60% or more.

According to the present invention, the quality of the electron beam can be improved in the electron beam generator for vapor deposition. Alternatively, according to the present invention, in the electron beam generator for vapor deposition, the temperature of the filament body can be raised or the temperature distribution of the filament body can be made uniform. Alternatively, according to the present invention, it is possible to suppress the emission of thermoelectrons from other than the filament body. Alternatively, according to the present invention, the life of the filament can be extended.

It is a side view which shows the electron beam generator which concerns on 1st Embodiment. It is a perspective view which shows the 1st example of a filament assembly. It is sectional drawing which shows the 1st example of a filament assembly. It is a side view which shows one filament leg and a sheath. It is a side view which shows the other filament leg and a sheath. It is sectional drawing which shows the 2nd example of a filament assembly. It is sectional drawing which shows the 3rd example of a filament assembly. It is sectional drawing which shows the 4th example of a filament assembly. It is sectional drawing which shows the 5th example of a filament assembly. It is a figure which shows the 1st modification of a filament. It is a figure which shows the modification of the attachment member. It is a figure which shows the deformation example of a structure. It is a figure which shows the 2nd modification of a filament. It is a side view which shows the electron beam generator which concerns on 2nd Embodiment. It is sectional drawing which shows the filament assembly which concerns on a comparative example. It is a figure which shows the vapor deposition apparatus.

Hereinafter, embodiments will be described with reference to the drawings.

(1) Outline of Embodiment The electron beam generator 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 member that holds the first held portion of the first filament leg. The second holding portion is a member that holds the second held portion of the second filament leg. The first enclosing portion is a member that non-contactly encloses the first enclosing portion existing on the filament body side of the first filament leg with respect to the first held portion. The second enclosing portion is a member that non-contactly encloses the second enclosing portion existing on the filament body side of the second filament leg with respect to the second held portion. In the first filament leg, the portion between the first held portion and one end of the filament body is the first exposed portion. In the second filament leg, the portion between the second held portion and the other end of the filament body is the second exposed portion. The ratio of the length of the first enclosed portion to the length of the first exposed portion is 60% or more. The ratio of the length of the second enclosed portion to the length of the second exposed portion is 60% or more.

Hereinafter, in some cases, the first filament leg and the second filament leg are both referred to as filament legs, the first held portion and the second held portion are both referred to as held portions, and the first enclosed portion and the second held portion are referred to. The enclosed portion is referred to as an enclosed portion, and the first exposed portion and the second exposed portion are both referred to as exposed portions. Further, the first holding portion and the second holding portion are both referred to as holding portions, and the first surrounding portion and the second surrounding portion are both referred to as surrounding portions.

According to the above configuration, since most of the exposed portion (specifically, 60% or more portion) of the filament leg is surrounded by the surrounding portion, all or a part of the plurality of advantages described below can be obtained.

The radiant energy emitted from the enclosed portion of the filament leg reaches the enclosing portion, and the radiant energy is absorbed in the enclosing portion. In the configuration example described later, heat conduction from the filament legs to the surrounding portion also occurs. Radiation (and heat conduction) raises the temperature of the enclosure. Since the enclosed portion of the filament leg is wrapped in a non-contact manner by the enclosing portion as a high temperature body, the temperature drop in the filament leg is suppressed and the heat outflow through the filament leg is suppressed. That is, the temperature of the filament legs is raised. As a result, the temperature of the filament body becomes high, or the temperature distribution in the filament body becomes uniform. 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 thermions emitted from the filament body can be increased. That is, the quality of the electron beam can be improved (first advantage).

For example, when the two filament legs are orthogonal to the thermoelectron extraction direction and the two surrounding portions are not provided, the thermoelectrons emitted from the two filament legs spread the electron beam. There is a risk. On the other hand, if the above configuration is adopted, the thermions emitted from the enclosed portion can be blocked by the enclosed portion, so that deterioration of the quality of the electron beam can be prevented or suppressed (second advantage).

According to the experiments of the present inventors, it has been confirmed that when the filament is used in an oxygen atmosphere, the life of the filament can be extended by adopting the above configuration. Specifically, when the surrounding portion is not used, oxidation is promoted at the intermediate portion of the filament leg, the diameter is reduced there, and finally fracture occurs. On the other hand, if the filament legs are wrapped in a non-contact manner by the surrounding portion, oxidation can be suppressed (third advantage). The reason may be that the temperature of the entire filament leg itself has risen, making it difficult for the filament leg to have an intermediate temperature that is likely to cause oxidation, and the surrounding area itself may have made it difficult for oxygen molecules to reach the filament leg. It can also be pointed out that the oxide particles released into the surrounding portion may make it difficult for oxygen molecules to reach the filament legs. It can also be pointed out that multiple oxidation suppression mechanisms may be working at the same time.

The length of the exposed portion is the length along the virtual central axis of the filament leg, and similarly, the length of the enclosed portion is along the virtual central axis of the filament leg. Is the length. The length of the enclosed portion is also the length of the enclosed portion. Each length is the length along the lumber axis. The material axis is an axis that passes through the center of gravity point on the cross section (cross section) at each position along the longitudinal direction of the member.

If the enclosed portion is not dominant in the exposed portion, specifically, if the ratio of the length of the enclosed portion to the length of the exposed portion is less than 60%, the filament due to heat outflow from both ends of the filament body. The temperature drop of the main body cannot be sufficiently suppressed, or the temperature varies in the filament main body. Therefore, in order to improve the quality of the electron beam, it is required that most or most of the exposed portion is the enclosed portion. Specifically, the ratio of the length of the enclosed portion to the length of the exposed portion is required to be 60% or more. In order to further improve the quality of the electron beam, the ratio should be 80% or more, particularly preferably 85% or more. The entire exposed portion itself may be surrounded by the enclosing portion, that is, the above ratio may be 100%. The above ratio may be 98% or less or 96% or less in order to surely avoid contact between the filament body and the surrounding portion.

In order for the surrounding portion to function sufficiently, it is better to bring the inner surface of the surrounding portion closer to the outer surface of the enclosed portion. That is, it is better to reduce the gap between them. However, the size of the gap is determined so that the contact between the enclosed portion and the enclosed portion can be reliably avoided.

Heat conduction occurs from the held portion of the filament leg to the holding portion. As long as the filament can be stably and surely held, if the held portion is made small, the amount of heat flowing out from the held portion to the holding portion can be reduced, and by extension, the temperature drop of the entire filament leg itself can be further suppressed. .. The ratio of the length of the held portion to the length of the entire filament leg may be, for example, 20% or less or 30% or less. In that case, the ratio may be 5% or more or 10% or more. Each length is a length along the central axis, as described above.

In the embodiment, the first siege portion has a tubular shape that absorbs heat radiated from the first siege portion and blocks thermions emitted from the first siege portion. The second siege portion has a tubular shape that absorbs heat radiated from the second siege portion and blocks thermions emitted from the second siege portion. According to this configuration, it becomes easy to raise the temperature of each enclosed portion as a whole uniformly. In addition, the manufacture and installation of each surrounding portion becomes easy.

The electron beam generator according to the embodiment further includes a first clamping mechanism that clamps the first surrounding portion and a second clamping mechanism that clamps the second surrounding portion. If the outer surface of each surrounding portion is a cylindrical surface, it is not necessary to consider the orientation when installing each surrounding portion. With the two clamping mechanisms, the two surrounding parts can be clamped stably and surely. Two clamps may clamp two retainers in addition to the two enclosures. Each clamp mechanism is a structure that functions as a fixing means or a holding means.

In the embodiment, the first holding portion and the first surrounding portion are integrated, and the second holding portion and the second surrounding portion are integrated. That is, the first holding portion and the first surrounding portion are composed of a single member, and the second holding portion and the second surrounding portion are composed of another single member. According to this configuration, the installation work of the first holding portion and the first surrounding portion and the installation work of the second holding portion and the second surrounding portion become easy. In addition, heat conduction from each holding portion to each surrounding portion can be improved.

In the embodiment, the first holding portion and the first surrounding portion constitute the first attachment member, and the second holding portion and the second surrounding portion constitute the second attachment member. The first attachment member and the second attachment member have the same form as each other. If the attachment method is adopted, that is, if the filament and the holding portion / surrounding portion are separated, the attachment member can be attached to the filament as needed. If the first attachment member and the second attachment member have the same form, it is not necessary to consider the type of the attachment member when installing the attachment member. Further, when the attachment member is worn out, it can be easily replaced.

It is also conceivable to provide a holding portion and a surrounding portion fixedly to each filament leg. For example, a filament in which the first holding portion, the second holding portion, the first surrounding portion and the second surrounding portion are integrated or assembled may be formed.

In the embodiment, the first holding portion and the first surrounding portion are first structures including a first cavity through which the first enclosed portion passes. The first structure absorbs the heat emitted from the first enclosed portion and blocks the thermions emitted from the first enclosed portion. The second holding portion and the second surrounding portion are second structures including a second cavity through which the second enclosed portion passes. The second structure absorbs the heat emitted from the second enclosed portion and blocks the thermions emitted from the second enclosed portion. The first structure and the second structure may be composed of one or more blocks, respectively. The first cavity and the second cavity are wells through which the enclosed portion passes in a non-contact manner, respectively. The bottom wall of the well corresponds to the holding part.

In an embodiment, the first filament leg has a first straight line portion including a first enclosing portion and an inclined portion connected to the first straight line portion via a bent portion. The second filament leg has a second straight portion including a second enclosing portion. The first surrounding portion extends to or near the bent portion. The length of the first siege and the length of the second siege are the same. According to this configuration, it becomes easy to avoid contact between the first filament leg (particularly the inclined portion thereof) and the first surrounding portion. Further, the shape of the first surrounding portion and the shape of the second surrounding portion can be made uniform. The inclined portion is a connecting portion between the first straight line portion and the filament body.

The attachment member according to the embodiment includes an enclosing portion that non-contactly encloses the filament legs in the filament that produces the electron beam. The surrounding portion has a hollow shape extending in the central axis direction of the filament legs. The filament leg is composed of a held portion and an exposed portion connected thereto. The exposed part is a part that is not in contact with other members. The surrounding portion surrounds the enclosed portion that is continuous with the held portion within the exposed portion. The ratio of the length of the enclosed portion to the length of the exposed portion is 60% or more. The attachment member is usually configured as a replaceable consumable, but may also be configured as a structure (ie, non-consumable) incorporated into the electron beam generator.

The attachment member according to the embodiment includes a bottom portion integrated with a surrounding portion. The bottom has a holding hole into which the held portion is inserted. This configuration facilitates filament installation. If the surrounding part and the holding part are integrated, they can be easily manufactured and handled.

In any type of thin film deposition filament, the filament body has a central axis parallel to the direction orthogonal to the beam extraction direction (first direction), in other words, one end of the filament body separated in the first direction. And the other end. In the filament in which the two filament legs extend in the second direction orthogonal to the first direction from both ends of the filament body, the filament body is in a complicated form such as a spiral form, a linear form, or curved. It has a form, etc. In that case, the filament body is defined as having a constant width in the second direction, with two portions exceeding that width being two filament legs. In a filament in which two filament bodies extend in parallel in the first direction from both ends of the filament body, the filament body has a non-linear shape such as a spiral shape or a plate shape. In that case, two portions beyond both ends of the portion having a non-linear morphology can be defined as two filament legs. When two parts having an L-shape are pulled out from both ends of a part having a non-linear shape, the non-linear part is defined as a filament body, and the two parts drawn from the filament body are defined as the filament body. It is defined as two filament legs.

(2) Details of the Embodiment FIG. 1 shows an electron beam generator 10 for vapor deposition according to the first embodiment. The electron beam generator 10 is arranged in a vacuum chamber of the vacuum vapor deposition apparatus. The electron beam generated by the electron beam generator 10 irradiates the vapor-deposited material in the crucible. _{When a metal oxide film such as silicon dioxide (SiO 2} ) film, zirconium oxide (ZrO ₂ ) film, titanium oxide (TiO ₂ ) film is formed on the surface of the object as a vapor deposition film, oxygen gas is produced in the vacuum chamber. Is introduced. However, the configuration described below can function effectively even when oxygen gas is not introduced into the vacuum chamber.

Although the electric circuit is also shown in FIG. 1, it is a supplementary and an example. 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 (vertical direction).

The component 12 is made of, for example, a conductive member such as copper, and the anode electrode 30 as a lead-out electrode is fixed to the component 12. The base 16 is connected to the component 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.

The pedestal pair 18 is composed of a pair of pedestals, which are fixed to the base 16, as will be described later. The pair of pedestals are physically and electrically separated from each other. The base 16 may be composed of a pair of base members.

Four blocks 22R, 24R, 22L, and 24L are mounted on the pedestal pair 18. They include two block pairs aligned in the x direction. Each block pair is composed of two blocks arranged in the y direction. Each block 22R, 24R, 22L, 24L is composed of a conductive member such as stainless steel or copper.

The filament 26 is made of, for example, tungsten. The filament 26 is a member that emits thermions by heat generation. As will be described later, the filament 26 is composed of a filament body and two filament legs (first filament leg and second filament leg). By passing a filament current through the filament 26, the filament 26 generates heat and becomes a very high temperature, and thermions are emitted from the filament 26. When the filament 26 is exhausted, it is replaced with a new one.

In the embodiment, the two filament legs of the filament 26 are surrounded by two sheaths 40, 42. The individual sheaths 40, 42 are made of, for example, a heat resistant metal or ceramic, and in embodiments, are made of stainless steel. Each of the sheaths 40 and 42 limits the heat outflow from the filament body by surrounding the filament legs, thereby raising the temperature of the filament body or making the temperature distribution of the filament body uniform. Depending on the installation mode and usage environment of the filament 26, in addition to the above-mentioned basic advantages, the sheaths 40 and 42 also provide a plurality of secondary advantages described later. The configuration and operation of each of the sheaths 40 and 42 will be described in detail later.

The filament assembly 300 according to the first example is composed of a filament 26, a pair of sheaths 40, 42, a pair of pedestals 18, and a plurality of blocks 22R, 24R, 22L, 24L. The two blocks 22R and 24R on the right side and the two blocks 22L and 24L on the left side function as clamp mechanisms, respectively. The two sheaths 40, 42 are clamped by the two clamping mechanisms, whereby the filament 26 is held. The beam shaping electrode 32 is provided so as to cover the filament body of the filament 26.

A constant voltage is applied between the two filament legs by the power supply 36, and a filament current is passed through the filament 26. As a result, the filament 26 generates heat, and thermions are emitted 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 thermions emitted from the filament 26 in a predetermined direction. This produces an electron beam 38.

The beam drawing direction is the −y direction. In the first embodiment, each filament leg is orthogonal to the beam drawing direction. In the second embodiment shown later in FIG. 14, each filament leg is parallel to the beam drawing direction.

A beam shaping electrode 32 is provided in order to manipulate the electric field in the vicinity of the filament 26 to generate a good electron beam 38. The arrangement and form of the filament 26, the anode electrode 30, the beam shaping electrode 32, and the like are examples. The electron beam 38 is deflected by a magnetic field formed by a permanent magnet or an electromagnet (not shown), and irradiates the vapor-deposited material in the crucible.

FIG. 16 shows a vacuum vapor deposition apparatus 200 based on an electron beam vapor deposition method. The inside of the vacuum container is a vacuum chamber 201, and an electron beam generator 202, a crucible 204, a cage 208, and the like are installed in the vacuum chamber 201. The vapor deposition material 206 is contained in the crucible 204. The dome-shaped cage 208 holds a plurality of objects (workpieces) 210. An electron beam 212 is generated in the electron beam generator 202, and the vapor deposition material 206 is irradiated with the electron beam 212. This causes the vaporized material 206 to evaporate (see reference numeral 214). As a result, a thin-film deposition layer is formed on the surfaces of the plurality of objects 210.

A turntable holding a plurality of crucibles may be arranged in the vacuum chamber 201. In that case, the vapor deposition material to be irradiated with the electron beam is selected by changing the rotation angle of the turntable. In order to form a good thin-film deposition layer efficiently or stably, it is desired to improve the quality of the electron beam 212 (particularly the beam morphology and thermionic density).

FIG. 2 shows the filament assembly 300 according to the first example as a perspective view. The two filament legs of the filament 26 are surrounded by two sheaths 40, 42. The pedestal pair 18 consists of two pedestals 18R and 18L arranged in the x direction.

Bolts for fastening the two blocks 22R and 24R arranged in the y direction are provided, but the illustration thereof is omitted. The clamp mechanism 320 is configured by the two blocks 22R and 24R and the bolts that fasten them. Bolts for fastening the two blocks 22L and 24L arranged in the y direction are provided, but the illustration thereof is also omitted. The clamp mechanism 322 is composed of the two blocks 22L and 24L and the bolts that fasten them.

The clamp mechanism 320 is a mechanism for sandwiching the sheath 40, and the clamp mechanism 322 is a mechanism for sandwiching the sheath 42. V-shaped grooves 44 for clamping are formed in the blocks 22R, 24R, 22L, and 24L, respectively. Sheaths 40, 42 may be retained by other mechanisms or structures. By the way, the two clamp mechanisms 320 and 322 are electrically insulated from each other.

FIG. 3 shows the front surface of the filament assembly 300 according to the first example. The filament 26 is composed of a filament body 46 and two filament legs 48 and 50. The filament 26 is manufactured, for example, by molding a linear member having a predetermined diameter. That is, in the embodiment, the filament body 46, the filament leg 48, and the filament leg 50 have a uniform cross-sectional shape (circular) and a uniform cross section, respectively, except for some bent portions generated during filament molding. Has a size. However, the cross-sectional shape and cross-sectional size of the filament main 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 pulled out from one end of the filament main body 46, and the filament legs 50 are pulled out from the other end of the filament main body 46.

The filament body 46 has a solenoid-like, that is, coil-like or spiral-like form, and its central axis 68 is parallel to the x direction. The central axis 68 is orthogonal to the beam drawing direction. The number of turns of the filament body 46 is, for example, in the range of 5 to 10. A filament body having another form other than the solenoid shape may be adopted. For example, a linear filament body, a spiral filament body, a plate filament body, and the like can be adopted.

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

The filament legs 48 are connected to one end (right end) of the filament body 46. The filament legs 50 are connected to the other end (left end) of the filament body 46. In the illustrated configuration example, the two filament legs 48 and 50 extend in a direction orthogonal to the central axis 68 of the filament body 46 (that is, in the z direction). One end and the other end of the filament body 46 are separated in the x direction.

The filament body 46 has a constant spread in the z direction. The level of its lower edge is indicated by z1. In the illustrated filament 26, the portion below the level z1 is defined as the filament legs 48,50. Similarly, when the filament body has a simple linear shape or the filament body has a spiral shape, two filament legs can be defined with reference to the filament body.

In the illustrated configuration example, the filament legs 48 and the filament legs 50 have the same shape as each other except for a part. First, the filament leg 48 will be described in detail.

The filament leg 48 is roughly classified into a held portion 62 and an exposed portion 63 connected to the held portion 62. The held portion 62 is a portion held by the sheath 40. The exposed portion 63 is a portion that is not in contact with other members. The exposed portion 63 is composed of an enclosed portion 64 and an exposed portion 65 connected thereto. The enclosed portion 64 is an intermediate portion surrounded by the sheath 40 in a non-contact manner, in other words, a portion below the opening of the sheath 40 and above the bottom portion 54 described later. The exposed portion 65 is a portion protruding from the sheath 40. The enclosed portion 64 and the non-holding portion form a straight portion.

In the filament leg 48, the exposed portion 65 constitutes an inclined portion (see reference numeral 65A). In this respect, the form of the filament leg 48 is different from that of the filament leg 50. In the filament leg 50, the exposed portion 65 is a straight portion (see reference numeral 65B).

The filament leg 48 has a central axis U as a virtual axis. The central axis U is a material axis that passes through the center of gravity point on the cross section of each position on the filament leg 48. As the length along the central axis U, the length of the filament leg 48 itself is indicated by U1, the length of the exposed portion 63 is indicated by U2, and the length of the enclosed portion 64 is indicated by U3. It is shown and the length of the exposed portion 65 is shown in U4. U3 is also the length of the tubular portion (surrounding portion) 52, which will be described later.

In the embodiment, in order to improve the quality of the electron beam, most or most of the exposed portion 63, specifically 60% or more thereof, is the enclosed portion 64. Specifically, the ratio of the length U3 of the enclosed portion 64 to the length U2 of the exposed 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 enclosed portion 64 to the length U2 of the exposed portion 63 is set to 80% or more, and more preferably 85% or more.

The form of the sheath 40 is defined so that the above numerical conditions are satisfied. The entire exposed portion 63 may be the enclosed portion 64. That is, the above ratio may be 100%. However, in order to avoid contact between the sheath 40 and the filament body 46, it is desirable that the above ratio is 98% or less or 96% or less.

The filament leg 50 has the same shape as the filament leg 48, except for a part, as described above. Specifically, the filament leg 50 is defined as a portion below z1 and is linear in its entirety. The filament leg 50 is roughly divided into a held portion 62 and an exposed portion 63, and the exposed portion 63 is composed of an enclosed portion 64 and an exposed portion 65. The exposed portion 65 of the filament leg 50 is parallel in the z direction (see reference numeral 65B). In this respect, the form of the filament leg 50 is different from that of the filament leg 48.

The filament leg 50 has a central axis V as a virtual axis. The central axis V corresponds to the material axis as described above. The length of each part is defined along the central axis V. Filament leg 50 The total length of the filament leg 50 is indicated by V1. In the filament leg 50, the length of the exposed portion 63 is indicated by V2, the length of the enclosed portion 64 is indicated by V3, and the length of the exposed portion 65 is indicated by V4.

In the embodiment, the same numerical conditions as the above numerical conditions are applied to the filament legs 50 from the viewpoint of improving the quality of the electron beam. That is, the ratio of the length U3 of the enclosed portion 64 to the length U2 of the exposed 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 enclosed portion 64 to the length U2 of the exposed portion 63 is set to 80% or more, and particularly preferably 85% or more. The form of the sheath 42 is determined so that the above numerical conditions are satisfied.

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 30% or less or 20% or less. In that case, the lower limit of the ratio may be 5% or more or 10% or more.

Next, the sheath 40 and the sheath 42 will be described in detail. The sheath 40 and the sheath 42 have the same configuration as each other. The sheath 42 will be described on behalf of them.

The sheath 42 is an attachment member. The sheath 42 has a tubular shape as a whole. The sheath 42 is made of a material that can withstand high temperatures, for example, metal, ceramic, or the like. Specifically, the sheath 42 is made of stainless steel. The sheath 42 may be made of tungsten. The outer surface of the sheath 42 is a cylindrical surface.

The sheath 42 is composed of a tubular portion 52 and a bottom portion 54. In reality, the sheath 42 is composed of a single member, that is, the tubular portion 52 and the bottom portion 54 are integrated. The tubular portion 52 and the bottom portion 54 may be separated and connected to each other.

The tubular portion 52 functions as a surrounding portion. The tubular portion 52 non-contactly surrounds the enclosed portion 64 of the filament leg 50. In the illustrated configuration example, the enclosed portion 64 can also be said to be an intermediate portion. Both the outer surface and the inner surface of the tubular portion 52 are cylindrical surfaces. The inner surface of the tubular portion 52 faces the internal space 58.

The wall thickness of the tubular portion 52 is set within the range of, for example, 0.1 to 4 mm, and is 0.3 mm in the illustrated configuration example. The inner diameter of the tubular portion is set within the range of, for example, 1 to 4 mm, and is 1.5 mm in the illustrated configuration example. The outer diameter of the tubular portion is set within the range of, for example, 2 to 12 mm, and is 2.1 mm in the illustrated configuration example. The distance between the surface of the filament leg 50 and the inner surface of the tubular portion 52 (see reference numeral 70) is set, for example, in the range of 0.1 to 1.6 mm, and in the illustrated configuration example, it is 0.35 mm. Is. The length of the exposed portion 63 is set, for example, within the range of 10 to 30 mm, and the length of the enclosed portion 64 is set, for example, within the range of 6 to 30 mm. In any case, each length is determined so that the above numerical conditions are satisfied. 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 within the range of, for example, 0.5 to 2.5 mm.

The bottom 54 is the bottom wall of the sheath 42, which serves as a retainer. The bottom portion 54 has a disk-like shape, and a holding hole 60 is formed in the center thereof. The non-holding portion (lower end portion) 62 of the filament leg 50 is detachably inserted into the holding hole 60, and the held portion 62 is held by the bottom portion 54. The held portion 62 and the inner surface of the holding hole 60 may be fixed. The filament 26 and the sheath 42 (and the sheath 40) may be integrated.

In the filament leg 50, the portion accommodated in the internal space 58 of the tubular portion 52 is the enclosed portion 64. The tubular portion 52 has a buried 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. As a result, the above numerical conditions are satisfied.

Except for the bottom 54, the shape of the sheath 42 is defined so that the sheath 42 does not come into contact with the filament 26. From the viewpoint of raising the temperature of the filament body 46 or making the temperature distribution uniform, it is better to increase the ratio of the lengths U3 and V3 of the enclosed portion to the lengths U2 and V2 of the exposed portion 63, but the sheath 40 From the viewpoint of surely preventing contact between the, 42 and the filament 26, it is desirable that the above ratio is less than 100%.

The thickness of each block in the z direction may be reduced in order to suppress the outflow of heat from the sheaths 40 and 42 to the blocks 24R and 24L (and the blocks 22R and 22L shown in FIG. 2).

As described above, the sheath 40 has the same configuration as the sheath 42. A large number of sheaths having the same shape 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-shaped groove inner surfaces 44A.

FIG. 4 is a right side view showing one filament leg 48 in 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 the bent portion 48c. The straight portion 48a corresponds to the enclosed portion 64 and the held 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.

The length U2 of the exposed portion 63 corresponds to the sum of the length U3 of the enclosed portion 64 and the length U4 of the inclined portion 48b (exposed portion 65). The upper end level of the sheath 40 is located at or near the bent portion 48c. FIG. 4 shows the thermions R emitted from the enclosed portion 64. Thermionic R is blocked by the inner surface of the sheath 40. This prevents deterioration of the quality of the electron beam due to thermionic R.

FIG. 5 is a right side view showing the other filament leg 50 of the filament 26. In FIG. 5, the elements already described are designated by the same reference numerals. Filament leg 50 The whole is linear. The filament leg 50 has an exposed portion 63, which is composed of an enclosed portion 64 and an exposed portion 65. The ratio of the length V3 of the enclosed portion 64 to the length V2 of the exposed portion 63 satisfies the above numerical condition. Also in the filament leg 50, the thermion R emitted from the enclosed portion 64 is blocked by the sheath 42, and the deterioration of the quality of the electron beam due to the thermion R is prevented.

In the configuration according to the above embodiment, the radiant energy emitted from each enclosed portion of each filament leg reaches the inner surface of each sheath. In addition, heat is supplied from each filament leg to each sheath by heat conduction. This raises the temperature of each sheath. At the same time, the temperature of each filament leg rises, and heat outflow through each filament leg is suppressed. As a result, the temperature of the filament body is raised, or the temperature distribution there is made uniform. This improves the quality of the electron beam.

In the filament assembly according to the first example, since the tubular portion and the bottom portion are integrated in each sheath, heat conduction from the bottom portion to the tubular portion is promoted. Further, the filament is detachably held by the two holding holes formed in the two bottoms, and it is not necessary to provide a complicated structure for holding the filament. The central axis of each filament leg and the central axis of each tubular portion coincide with each other.

FIG. 6 shows the filament assembly 302 according to the second example. FIG. 6 shows a horizontal cross section of the filament assembly 302. A rectangular well 72A is formed in the block 72 when viewed from the z direction, and a rectangular well 74A is also formed in the block 74 when viewed from the z direction. A rectangular sheath 76 viewed from the z direction is partially inserted into the well 72A, and a rectangular sheath 78 viewed from the z direction is partially inserted into the well 74A. The enclosed portions of the filament legs 49R and 49L are housed inside the sheaths 76 and 78. As described above, the prismatic sheaths 76 and 78 may be adopted.

FIG. 7 shows the filament assembly 304 according to the third example. The block 82 is mounted on the pedestal 80, and the block 84 is mounted on the pedestal 81. A through hole is formed in the block 82, and a tubular sheath 86 is inserted therein. Similarly, a through hole is formed in the block 84, and a tubular 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 pedestals 80 and 81. The filament 90 has filament legs 92,94. The pedestal 80 has a holding hole 96 for holding the held portion (end) 92A of the filament leg 92. The pedestal 81 has a holding hole 98 for holding the held portion (end) 94A of the filament leg 94. The end faces of the held portions 92A and 94A abut against the bottom surfaces of the holding holes 96 and 98.

Each of the sheaths 86 and 88 is configured to satisfy the above numerical conditions. That is, in each of the filament legs 92 and 94, the ratio of the lengths U3 and V3 of the enclosed portion 64 to the lengths U2 and V2 of the exposed portion 63 is 60% or more, preferably 80% or more.

FIG. 8 shows the filament assembly 306 according to the fourth example. The filament 110 has filament legs 112, 114. The block 102 is mounted on the pedestal 100, and the block 104 is mounted on the pedestal 101. A well 106 is formed in the block 102, and a well 108 is formed in the block 104. A through hole is formed in the bottom portion 102B of the well 106, and a held portion (end portion) 112A of the filament leg 112 is inserted into the through hole. A through hole is formed in the bottom portion 104B of the well 108, and a held portion (end portion) 114A of the filament leg 114 is inserted into the through hole. Each through hole functions as a holding hole.

In the blocks 102 and 104, the portions 102A and 104A surrounding the wells 106 and 108 function as surrounding portions, respectively. The bottom portions 102B and 104B of the blocks 102 and 104 function as holding portions. The portions 102A and 104A surrounding the wells 106 and 108 become high temperature portions, and as a result, the temperatures of the filament legs 112 and 114 are raised and the heat outflow from them is suppressed. The inside of the wells 106 and 108 constitutes two cavities 106A and 108A, and the enclosed portions of the two filament legs 112 and 114 pass through the cavities 106A and 108A.

In the configuration according to the fourth example, the blocks 102 and 104 as the structure function as the surrounding portion and the holding portion as described above. Further, the blocks 102 and 104 may function as clamp members.

Each of the blocks 102 and 104 is configured to satisfy the above numerical conditions. That is, in each of the filament legs 112 and 114, the ratio of the lengths U3 and V3 of the enclosed portion 64 to the lengths U2 and V2 of the exposed portion 63 is 60% or more, preferably 80% or more.

FIG. 9 shows the filament assembly 308 according to the fifth example. The filament 120 has a filament body 122 and filament legs 124,126. 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 axes of the filament legs 124 and 126 are parallel to the central axis of the filament body 122.

The sheaths 128 and 130 are composed of a tubular portion 136, 140 and a bottom portion 138, 142, respectively. The held portions (ends) 124A and 126A of the filament legs 124 and 126 are held by the bottom portions 138 and 142 as holding portions. The enclosed portions of the filament legs 124 and 126 pass through the inside of the tubular portions 136 and 140. The sheaths 128 and 130 are held by blocks 132 and 134.

Also in the configuration according to the fifth example, the sheaths 128 and 130 are configured so that the above numerical conditions are satisfied. That is, in each of the filament legs 124 and 126, the ratio of the lengths U3 and V3 of the enclosed portion to the lengths U2 and V2 of the exposed portions is 60% or more, and preferably 80% or more. The complex portion (spiral portion) in which the surface area is increased is the filament main body 122, and the two straight portions drawn out from both ends thereof are the two filament legs 124 and 126.

FIG. 10 shows a first modification of the filament. The elements already described are designated by the same reference numerals and the description thereof will be omitted. This also applies to FIG. 11, which will be described later.

In FIG. 10, the ends of the two filament legs of the filament 26A have an L-shaped shape. Specifically, the end of the filament leg 150 passes through a holding hole 60 formed in the bottom 54 of the sheath 40. The end portion is composed of a first portion 150d connected to the enclosed portion and a second portion 150e connected to the first portion 150d. The first portion 150d is parallel in the z direction and the second portion is parallel in the y direction. There is a bend between them. In the configuration shown in FIG. 10, the first portion 150d is the held portion. The entire end may be the held portion.

The entire filament leg itself may be L-shaped. In that case, the end portion may be L-shaped in the same manner as described above.

FIG. 11 shows a modified example of the sheath (attachment member). The bipartite sheath 152 is composed of a first portion 152a and a second portion 152b. A groove 154a is formed at the bottom of the first portion 152a, and a groove 154b is formed at the bottom of the second portion 152b. The sheath 152 is formed by the union of the first portion 152a and the second portion 152b, and at this time, the held portion of the filament leg 150 is held by the two grooves 154a and 154b. The two grooves 154a, 154b function as holding holes 154 in their combined state.

FIG. 12 shows a modified example of the structure holding the filament. The coupling of the blocks 156 and 158 holds the filament legs 150 of the filament 26A. The other filament leg is also held by a similar structure.

The 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 coupling of block 156 and block 158 holds the filament leg 150.

Specifically, in the bonded state, the two grooves 164A and 164B are united to function as a holding hole, and the held portion of the filament leg 150 is held by the two grooves 164A and 164B. In the bonded state, the two recesses 160A and 160B are united to form a cavity 160 that accommodates the enclosed portion of the filament leg 150. The circumference of the cavity 160 functions as a siege. The lower portion of the cavity 160 functions as a retainer.

FIG. 13 shows a modified example 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 the filament legs 170 and 172 extend in the z direction. The cross section of the filament body 168 has, for example, a semicircular shape, a D shape, a flat plate shape, or the like. In this modification, the main portion that emits thermions is the portion that is parallel to the x direction, which is the filament body 168. That is, in the z direction, the range indicated by reference numeral 174 corresponds to the filament body 168. The parts below that, specifically the two parts within the range indicated by reference numeral 175, are the filament legs 170 and 172. Two sheaths are attached to the two filament legs 170 and 172.

FIG. 14 shows the electron beam generator for vapor deposition according to the second embodiment. In the first embodiment, the filament having a vertical posture is installed in the electron beam generator, but in the second embodiment, the filament 26 having a horizontal posture is installed in the electron beam generator. The clamp mechanism 184 holds two sheaths 40, 42 having a horizontal posture. The two sheaths 40, 42 surround the enclosed portion of the two filament legs and hold the retained portion of the two filament legs. Reference numeral 30 indicates an anode electrode for thermionic extraction, and reference numeral 186 indicates a beam shaping electrode. The beam drawing direction is the −y direction. Reference numeral 38 indicates an electron beam.

Also in the second embodiment, the sheaths 40 and 42 are provided so that the above numerical conditions are satisfied. As a result, the temperature of the filament body can be raised, or the temperature distribution thereof can be made uniform, so that the quality of the electron beam can be improved.

FIG. 15 shows a comparative example. The filament 220 is made of tungsten, which is placed in a vacuum chamber. Oxygen gas is introduced into the vacuum chamber. That is, the filament 220 is in an oxygen atmosphere.

The filament 220 is composed of a filament body 222 and two filament legs 224,226. The filament legs 224 are sandwiched by the right block pair (FIG. 16 shows only one block 228 of the right block pairs), and the filament legs 226 are sandwiched by the left block pair (FIG. 16). FIG. 16 shows only one block 230 of the left block pair). The filament body 222 is a high temperature part. A temperature gradient occurs in the exposed portion of each filament leg 224,226. In particular, in the intermediate portions 232 and 234 of each exposed portion, an intermediate temperature that is easily oxidized is generated. The melting point of tungsten oxide is lower than that of tungsten, and the oxidized portion evaporates, which promotes the reduction in diameter of the intermediate portions 232 and 234. If the oxidation further progresses, the intermediate portions 232 and 234 will be broken.

According to the configuration according to the embodiment, the exposed portion of each filament leg is surrounded by a surrounding portion to increase the temperature of each filament leg itself. Thereby, the generation of the above-mentioned intermediate temperature can be effectively avoided. That is, the life of the filament can be increased. Experiments have confirmed that the life of the filament can be tripled.

According to the configuration according to the embodiment, the quality of the electron beam can be improved. The advantage is obtained with or without oxygen in the vacuum chamber. In particular, the advantage of increasing the temperature of the filament body or making the temperature distribution uniform can be obtained in both the configuration according to the first embodiment and the configuration according to the second embodiment. The configuration according to the embodiment may be applied to other electron beam generators.

10 electron beam generator, 26 filaments, 38 electron beams, 40, 42 sheaths, 46 filament bodies, 48, 50 filament legs, 52 tubular parts (surrounding part), 54 bottom parts (holding part).

Claims (10)

A filament body, a filament having 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 the first held portion of the first filament leg, and a first holding portion.
A second holding portion that holds the second held portion of the second filament leg, and a second holding portion.
A first enclosing portion that non-contactly encloses a first enclosing portion existing on the filament body side of the first filament leg with respect to the first held portion.
A second enclosing portion that non-contactly encloses the second enclosing portion existing on the filament body side of the second filament leg with respect to the second held portion.
Including
In the first filament leg, the portion between the first held portion and one end of the filament body is the first exposed portion.
In the second filament leg, the portion between the second held portion and the other end of the filament body is the second exposed portion.
The ratio of the length of the first enclosed portion to the length of the first exposed portion is 60% or more.
The ratio of the length of the second enclosed portion to the length of the second exposed portion is 60% or more.
An electron beam generator for vapor deposition, which is characterized by this. In the electron beam generator for vapor deposition according to claim 1,
The ratio of the length of the first enclosed portion to the length of the first exposed portion is 80% or more.
The ratio of the length of the second enclosed portion to the length of the second exposed portion is 80% or more.
An electron beam generator for vapor deposition, which is characterized by this. In the electron beam generator for vapor deposition according to claim 1,
The first encircling portion has a tubular shape that absorbs heat radiated from the first enclosing portion and blocks thermions emitted from the first enclosing portion.
The second encircling portion has a tubular shape that absorbs heat radiated from the second enclosing portion and blocks thermions emitted from the second enclosing portion.
An electron beam generator for vapor deposition, which is characterized by this. In the electron beam generator for vapor deposition according to claim 3.
A first clamping mechanism that clamps the first surrounding portion and
A second clamping mechanism that clamps the second surrounding portion, and
An electron beam generator for vapor deposition, which comprises. In the electron beam generator for vapor deposition according to claim 1,
The first holding portion and the first surrounding portion are integrated, and the first holding portion and the first surrounding portion are integrated.
The second holding portion and the second surrounding portion are integrated.
An electron beam generator for vapor deposition, which is characterized by this. In the electron beam generator for vapor deposition according to claim 5.
The first attachment member is composed of the first holding portion and the first surrounding portion.
The second attachment member is formed by the second holding portion and the second surrounding portion.
The first attachment member and the second attachment member have the same form as each other.
An electron beam generator for vapor deposition, which is characterized by this. In the electron beam generator for vapor deposition according to claim 1,
The first holding portion and the first surrounding portion are first structures including a first cavity through which the first enclosed portion passes.
The first structure absorbs the heat released from the first enclosed portion and blocks the thermions emitted from the first enclosed portion.
The second holding portion and the second surrounding portion are second structures including a second cavity through which the second enclosed portion passes.
The second structure absorbs the heat released from the second enclosed portion and blocks the thermions emitted from the second enclosed portion.
An electron beam generator for vapor deposition, which is characterized by this. In the electron beam generator for vapor deposition according to claim 1,
The first filament leg has a first straight line portion including the first enclosed portion and an inclined portion connected to the first straight line portion via a bent portion.
The second filament leg has a second straight portion including the second enclosed portion.
The first surrounding portion extends to the bent portion or its vicinity, and extends to the bent portion or its vicinity.
The length of the first siege and the length of the second siege are the same.
An electron beam generator for vapor deposition, which is characterized by this. Includes a non-contact enclosure around the filament legs in the filament that produces the electron beam.
The surrounding portion has a hollow shape extending in the central axis direction of the filament leg.
The filament leg is composed of a held portion and an exposed portion connected thereto.
The surrounding portion surrounds the enclosed portion connected to the held portion within the exposed portion.
The ratio of the length of the enclosed portion to the length of the exposed portion is 60% or more.
An attachment member for an electron beam generator. In the attachment member according to claim 9,
Includes a bottom integrated with the enclosure
The bottom has a holding hole into which the held portion is inserted.
An attachment member for an electron beam generator.

Images