JP3025095B2 - Long electron beam generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electron gun as an electron beam generator which is a heat source for generating metal vapor or the like in a vacuum.

[0002]

2. Description of the Related Art For example, a vapor deposition apparatus is an apparatus for converting a metal or the like into a vapor and depositing the vapor on the surface of an object, and irradiates an electron beam as a means for heating, melting and vaporizing the metal or the like. ing. For this reason, an electron beam generator is required, and a long one is required. As an example of a cathode for generating electrons in such an electron beam generator as an electron gun, there is one having a structure shown in FIG.

FIG. 5 shows an electron impact type indirectly heated cathode, which has a heating filament 18 for the cathode body 2 and a filament heating power source 21 as a power source, and between the filament 18 and the cathode body 2. A bombardment power supply 19 is provided, and the cathode main body 2 is supported by support slide pins 20.

However, the following problem occurs in the electron impact type indirectly heated cathode shown in FIG. Cathode body 2, cathode heating filament 18,
Many parts such as a bombardment power supply 19 and a filament power supply 21 are required and the structure is complicated. In order to obtain a uniform temperature distribution, it is necessary to keep the distance between the cathode body 2 and the filament 18 with high accuracy.
It is difficult to maintain high precision in combination with the lengthening. Since the cathode main body 2 and the filament 18 have a support structure at both ends, there is a limit to lengthening.

Although there is a so-called direct heat type cathode in which the cathode body itself is also a filament, unlike FIG. 5, there are the following problems. Consumption due to sputtering and overheating disconnection easily occur, and the life is short. The cathode support structure considering thermal expansion becomes complicated. The electron beam is deflected by the magnetic field created by the current flowing through the cathode body, making it difficult to obtain uniformity of the electron beam. Since the cathode body has a support structure at both ends, there is a limit to lengthening the cathode body.

In view of the above-mentioned problems, the present invention eliminates the drawbacks of the indirectly heated cathode having a complicated structure, difficulty in achieving high precision, and a limitation in elongation. It is an object of the present invention to provide a long electron beam generator which eliminates the drawbacks of difficulties in uniformity and limitation of lengthening.

[0007]

SUMMARY OF THE INVENTION The present invention, which achieves the above objects, comprises: (1) a long electron beam generator for generating an electron beam irradiated on a metal or the like to obtain a vapor of the metal or the like; A rectangular parallelepiped cathode, a heat-resistant insulating layer covered except for the electron-emitting surface of the cathode, and a central portion in the longitudinal direction of the cathode that is coated so as to surround the electron-emitting surface and extend around the heat-resistant insulating layer. It is characterized by including a heater from which a current introduction terminal is further derived, and a second heat-resistant insulating layer further covered on an upper layer of the heater.

(2) In a long electron beam generator for generating an electron beam irradiated on a metal or the like in order to obtain a vapor of the metal or the like, a long rectangular parallelepiped lanthanum hexaboride sintered body; A pyrolytic graphite layer coated except for the electron emission surface of the lanthanum boride sintered body, a pyrolytic boron nitride layer coated on the pyrolytic graphite layer, and a pyrolytic boron nitride layer on the pyrolytic boron nitride layer A pyrolytic graphite layer that is a heater that is coated so as to surround the electron emission surface and that has a current introduction terminal led out from the center in the longitudinal direction of the lanthanum hexaboride sintered body, and an upper layer of the pyrolytic graphite that is the heater And a pyrolytic boron nitride layer further coated.

[0009]

[Function] The cathode body itself is formed in a long rectangular parallelepiped shape as an indirectly heated cathode, and a heater can be precisely formed on the cathode body based on the cathode body. The magnetic field can be canceled by flowing. In addition, the cathode can be freely supported by coating the heat-resistant insulating layer.

[0010]

An embodiment of the present invention will now be described with reference to FIGS. FIG. 1 shows the overall configuration. In FIG.
1 is a heat-resistant insulating ceramic such as pyrolytic boron nitride, and 2 is a long rectangular parallelepiped lanthanum hexaboride (La).
B ₆ ), a cathode body, 23 is a graphite intermediate layer formed at the boundary between the ceramics 1 and the cathode body 2, 3 is a heater made of pyrolytic graphite or the like deposited on the ceramics 1. To form an indirectly heated linear integrated cathode that generates electrons.

The indirectly heated cathode has an introduction terminal 15 connected to the heater 3 and connected to the DC power supply 11. The cathode is supported by the support insulator 16.
Further, the cathode is provided with a heat shield and an electric field shield by a reflection shield plate 14. A grid 4 applies a negative voltage to the cathode main body 2 by a grid power supply 12 to control the amount of electron beams and the beam focusing property. Reference numeral 5 denotes an anode, which applies a positive voltage to the cathode main body 2 by an acceleration power supply 13 to extract thermoelectrons from the cathode and accelerate the electron beam 6. Reference numeral 7 denotes a uniform magnetic field, and the electron beam 6 is deflected to 270
° Target 8 in water-cooled crucible 9 provided at deflection position
The target 8 is heated and melted and vaporized to obtain a vapor of metal or the like. Reference numeral 10 in the crucible 9 is a cooling water hole.

In the overall structure shown in FIG. 1, the details of the integrated cathode will be described together with the manufacturing method. 2 and 3, for example, a lanthanum hexaboride (LaB ₆ ) sintered body formed in a long rectangular parallelepiped shape is first formed as the cathode main body 2. Except for the electron emission surface of the cathode main body 2, the periphery thereof is coated with a heat-resistant insulating ceramic 1 such as pyrolytic boron nitride by vapor deposition (CVD). In this case, the graphite layer 23 may be deposited on the cathode main body 2 before the ceramic 1 is coated, and then the ceramic 1 may be coated. This graphite layer 23
Is provided to reduce the reaction between lanthanum hexaboride as the cathode main body 2 and boron nitride as the ceramics 1, and is effective for high-temperature long-time operation.

A heater 3 made of pyrolytic graphite or the like is further deposited and coated on the ceramics 1 by a CVD method so as to extend around the periphery except for the electron emission surface and the back surface.
The heater 3 is then machined to form the shape shown in FIG. 2 (b), and a current lead-out terminal 15 is similarly formed from the center in the longitudinal direction. Thereafter, a heat-resistant insulating ceramic is deposited and coated thereon to obtain a cathode having an insulating coating structure.

[0014] Since the thermal expansion coefficients of the constituent materials at 1800 ° K are not significantly different, there is no concern about breakage due to heating. As the expansion coefficient, lanthanum hexaboride (La
L ₆ ) = 0.8%, boron nitride (BN) = 1.0%,
Graphite (C) = 0.7%.

Since it is conceivable that the integrated cathodes in this embodiment are further arranged in series in the longitudinal direction, the heater structure shown in FIG. 4 can be configured so that the cathode bodies can be easily arranged in the longitudinal direction. .

[0016]

According to the present invention as described above, the following effects can be obtained. Since the cathode body and the heater are of an integral structure, the size and structure are simple and accurate, and the cost and maintenance of the electron gun can be reduced. Long life. Heat conduction heating is performed via the thin heat-resistant insulating layer, so that the response of the cathode temperature control is improved, the beam output stability is increased, and the quality such as the uniformity of the deposited film thickness is improved. Since the cathode is insulated and coated, it is not necessary to adopt a support structure at both ends as in the conventional method.Since it can be supported on the entire surface, the cathode support structure is simplified, and the cathode is made longer and multiple cathodes are installed in series. , The electron beam can be lengthened, and it is easy to increase the size and output. Since the heater current is in a direction parallel and opposite to the electron emission surface, the magnetic field generated by the current is canceled on the electron emission surface, and no electron beam deflection occurs.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram.

2A is a perspective view of a cathode, and FIG. 2B is a perspective view of a heater.

3A is a plan view of a cathode, FIG. 3B is a front view,
(C) is a side view, and (d) is a diagram showing a cross section taken along line AA of (b).

FIG. 4 is a perspective view of another example of the heater.

FIG. 5 is a perspective view of a conventional cathode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat-resistant insulating ceramic 2 Cathode 3 Heater 15 Current introduction terminal 23 Graphite intermediate layer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Susumu Urano 4-6-22 Kannon Shinmachi, Nishi-ku, Hiroshima-shi, Hiroshima Mitsubishi Heavy Industries, Ltd. Hiroshima Works (72) Inventor Shigeo Konno 3-1-1 Musashino, Akishima-shi, Tokyo No. 2 Inside Nihon Denshi Co., Ltd. (72) Inventor Toru Takashima 3-1-2 Musashino, Akishima-shi, Tokyo Nihon Denshi Co., Ltd. (56) References JP-A-3-184230 (JP, A) JP Hei 3-266344 (JP, A) Japanese Utility Model Showa 61-83245 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01J 37/06 C23C 14/30

Claims (2)

(57) [Claims] 1. A long electron beam generator for generating an electron beam irradiated on a metal or the like to obtain a vapor of the metal or the like, comprising a long rectangular parallelepiped cathode and a coating except for an electron emission surface of the cathode. A heat-resistant insulating layer, a heater which surrounds the electron emission surface and extends around the heat-resistant insulating layer, and further has a current introduction terminal led out from a longitudinal central portion of the cathode, and further covers an upper layer of the heater. And a second heat-resistant insulating layer. 2. An elongated electron beam generator for generating an electron beam irradiated on a metal or the like in order to obtain a vapor of a metal or the like, comprising: an elongated rectangular parallelepiped lanthanum hexaboride sintered body; A pyrolytic graphite layer coated except for the electron emission surface of the lanthanum sintered body; a pyrolytic boron nitride layer coated on the pyrolytic graphite upper layer; and an electron emission layer on the pyrolytic boron nitride upper layer. A pyrolytic graphite layer which is a heater which is coated so as to surround the surface and which has a current introduction terminal derived from the longitudinal center of the lanthanum hexaboride sintered body; and an upper layer of the pyrolytic graphite which is a heater. A coated pyrolytic boron nitride layer; and a long electron beam generator.