JPS63109161A - Electron ray heating and melting device - Google Patents

Abstract

PURPOSE:To improve the heating efficiency of a metal by an electron beam by utilizing the electron beam reflected on a metal surface and the secondary electrons from the metal for heating the metal at the time of heating, melting and evaporating the metal, etc., by the electron beam. CONSTITUTION:The inside of a vacuum vessel 1 is evacuated to a vacuum by an evacuation system 2 and the metal 8 for vapor deposition in a crucible 4 having water cooling pipes 5 and ceramic lining 6 is irradiated with the electron beam 10 from an electron gun 7, by which the metal is heated, melted and evaporated to generate metal vapor 14 for vapor deposition. The electron beam 11 which is reflected from the surface of the metal 8 and is not utilized for heating the metal 8 and the beam of the secondary electrons generated from the molten metal are again deflected in the direction by a magnetic field 13 for deflecting the electron beam 10 from the gun 7 to irradiate the surface of the metallic material 9 in a device 3 for supplying the metallic material for vapor deposition, by which the metallic material is heated and melted. The molten metal is supplied through a trough into the crucible 4. The heating efficiency of the metal by the electron beam is greatly improved by the effective utilization of the electron beam 10 and the secondary electron.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an apparatus for heating, melting, and evaporating metals, etc. using an electron beam, and particularly relates to an improvement for improving the energy utilization efficiency of the electron beam.

[Prior art] Compared to other heating methods, heating methods using electron beams have advantages such as high energy density and the ability to arbitrarily control the beam with high precision, especially for melting high melting point materials. , vapor deposition, etc.

FIG. 2 schematically shows an electron beam evaporation apparatus that is an example of electron beam heating. The electron beam 10 emitted from the electron gun 7 is deflected by 180 degrees by a magnetic field created by a deflection magnet 18 and guided to a material 8 such as metal for internal illumination of the crucible 4 . Steam 14 generated from the deposition material 8 heated by the electron beam reaches the substrate 19 installed above, where it forms an A-deposition film.

By the way, it is known that the portion of electrons incident on the heated/molten material 8 is reflected without losing much of its energy. For example, Sov.

Tech, Phym, Lett, 8(1) 198
2 pp. 35-37, a small portion of the electrons incident on the metal surface is reflected back without losing much of its energy. At this time, the reflection coefficient rl, that is, the ratio of the number of electrons incident on the metal surface to the number of reflected electrons, is approximately r ” 0.3 For soot r! 0.4 For gold r m Q,5.

Now consider gold as a deposition material. The acceleration voltage of electrons is 10
kV, emission of the filament of an electron gun that generates electrons/? If the JE current is 2000 mA, the output of the electron gun will be 20 kW. According to the above-mentioned paper, the reflection coefficient for gold is 0.5.

Therefore, of the 20 kW output from the electron gun, the energy used to heat the gold is actually 10 kW), and the remaining 10 kW is wasted due to electron reflection on the entire surface. . Traditional! In tl, no particular consideration was given to the reflected electrons, and the heating and melting efficiency was poor.

Therefore, as described in Japanese Patent Application Laid-Open No. 59-173264, one part of the main body of a water-cooled copper crucible that holds the metal material to be deposited is
! The 0 wall is tilted and extended to a height where it receives the electron beam from the electron gun that is incident on and reflected by the metal material for evaporation supplied in the Ludde, and the electron beam reflected from the metal material for evaporation is erected. It is reflected by the inner surface of the extended side wall,
The electron beam enters the metal material for deposition again without being emitted in all directions, and the metal material for deposition is heated by this electron beam.The heating effect of the electron beam from the electron gun is sufficiently improved. It is also being considered that the energy of backscattered electrons can be effectively used to improve vapor deposition efficiency.

[Problems to be Solved by the Invention] The above-mentioned prior art takes into consideration the fact that when reflected electrons are incident on the inner surface of one side wall extended upright of a water-cooled copper crucible, they are not only reflected but also absorbed. There was a problem that the energy utilization efficiency of reflected electrons was not sufficient.

An object of the present invention is to further increase the utilization efficiency of reflected electrons and to increase the heating efficiency of electron beams.

Means for Solving Problem U] The above purpose is to eliminate electrons emitted from an electron gun and reflected by the material to be heated and melted, and electrons emitted from the electron gun and generated there when they enter the material to be heated and melted. This is achieved by arranging the material supply device so that the secondary electrons generated by the heat and melt hit the material supply device to be heated or the material to be melted.

Note that the trajectory of the electron beam emitted from the electron gun may be a straight line or may be curved due to the magnetic field.

[Operation] The electron beam emitted from the electron gun collides with the heated and melted material. A portion of the electron beam is used to heat the material, while the remainder is reflected. Further, secondary electrons are generated from the above materials. The reflected electrons and secondary electrons collide with the heated molten material supply device or the feed material, and indirectly or directly heat the feed material.

By applying a magnetic field perpendicular to the traveling direction of the reflected electrons and secondary electrons, the direction of movement of the reflected electrons and secondary electrons is bent.
Entry into the feed material or the feed device can be facilitated.

[Example code] Embodiments of the present invention will be described below with reference to FIG.

As shown in FIG. 1, a crucible 4 is placed in a vacuum chamber 1 kept in vacuum by an exhaust system 2, and a metal material 8 for vapor deposition is held in its recess. In order to prevent damage to the crucible 4 due to temperature rise, the crucible 4 is water-cooled by flowing cooling water through the cooling water pipe f5. 4 and metal material for deposition 8
Ruth in direct contact? In order to prevent the crucible 4 from reacting and to prevent heat from dissipating from the walls of the crucible 4, the inner surface of the recessed portion of the crucible 4 is lined with a lining 6 made of ceramic, wood, or the like. The electron gun 7 is placed at a position where it cannot directly view the surface of the metal material for vapor deposition 8 to avoid contamination by the vapor of the metal material for vapor deposition 14 . The electrons 10 emitted from the electron gun 7 are deflected in the direction of travel by a magnetic field 13 that is directed from the back side of the page to the front side.
It is deflected by .degree. and is incident on the surface of the metal material for deposition 8. At this time, the backscattered electrons 11 that are not absorbed by the metal material for vapor deposition 8 but are reflected and ejected again are bent in their traveling direction by the magnetic field 13 again, and the metal material for vapor deposition device 3 adjacent to the stubble 4 and inside the metal material for vapor deposition device 3 are moved. The light enters the surface of the metal material for vapor deposition 9 held by the metal material for vapor deposition, and contributes to the heating of the metal material for vapor deposition 9.

The metal material supply device 3 for vapor deposition supplies emitted electrons l from the electron gun.
It is desirable to make the length long in the traveling direction of the reflected electrons on the surface of O and the metal material for vapor deposition. This is because the probability that the reflected electrons will be incident on the deposition metal material supply device 3 or the deposition metal material 9 held therein is increased, and the utilization efficiency of the electron beam is increased.

By the incidence of backscattered electrons, the preheated or melted metal material for deposition passes through the bridge portion as shown in the figure. 4.

According to the embodiment of the present invention as described above, after the metal material 9 for deposition is preheated or melted using reflected electrons, the metal material 9 is melted. 4, the energy utilization efficiency of the electron gun 7 can be greatly improved.

The bridge portion of the metal material supply device 3 for vapor deposition may or may not have an upper lid 15. This is because the preheating of the metal material for deposition may be performed by direct irradiation with electron beams or by indirect heating.

[Effects of the Invention] According to the present invention, since reflected electrons and secondary electrons from the material to be melted can be reused, the energy utilization efficiency of the electron gun can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a metal evaporation apparatus using an electron beam, which is an embodiment of the present invention, and is equipped with an apparatus for supplying metal material for evaporation, and FIG. 2 is a diagram showing an ordinary evaporation apparatus using an electron beam. 1... Vacuum chamber 2... Exhaust system 3... Metal material supply device for deposition 4... Ruth? 5... Vibro for cooling water
... Lining 7 ... Electron gun 8 ... Metal material to be heated 9 ... Metal material for supply 10 ... Emitted electrons from the electron gun 11 ... Backscattered electrons 12 on the surface of the metal material for deposition ...
Backscattered electrons 13...Magnetic field 14...Metal vapor 15...Metal material supply device for vapor deposition Tower top lid 16...
Backscattered electrons with low energy 18...Bending magnet
19...Substrate. Kota Tani, 2” 13-・Magnetic field

Claims (1)

[Claims] 1. In an electron beam heating melting apparatus comprising an electron gun and a means for holding a heated melting material, electrons emitted from the electron gun and reflected by the heated melting material and the heated melting material An electron beam heating and melting apparatus characterized in that the supplying device is arranged so that the generated secondary electrons hit the heating and melting material supplying device or the heated and melting material inside the heating and melting material supplying device. 2. The electron beam heating melting apparatus according to claim 1, wherein the reflected electrons and the secondary electrons are deflected using a magnetic field.