JP2011119140A - Electron beam device - Google Patents

Abstract

An object of the present invention is to suppress consumption of a cathode and extend its life.
An electron beam from an electron gun 5 having a filament 60 '(cathode), a grid 7 and an anode 8 with a central portion evacuated is applied to an evaporating substance 3 so that evaporating particles adhere to the substrate in a film form. The electron beam vapor deposition apparatus is configured such that the tip surface of the electron gun 5 is positioned on the central axis O ′ of the electron gun 5 so as to be positioned in the central space of the filament 60 ′ (cathode) when viewed from the anode 8. A collector 20 is provided, and a metal plate 21 is provided on the side opposite to the filament 60 ′ (cathode) side as viewed from the anode 8, and titanium particles generated from the ion collector 20 generated by sputtering are deposited on the metal plate 21. The oxygen gas around the electron gun 5 was adsorbed on the deposited titanium.
[Selection] Figure 4

Description

  The present invention relates to an electron beam apparatus capable of suppressing the consumption of a cathode and extending its life.

  As an electron beam device, the substance is evaporated by applying it to the substance contained in the crucible, the evaporated particles are adhered to the substrate, or the accelerated electron beam is collided with the target to be welded to the target. There is a device that performs processing.

  FIG. 1 shows an outline of an electron beam evaporation apparatus as an example of such an electron beam apparatus, and FIG. 2 is a cross-sectional view taken along line AA of FIG.

  In FIG. 1, reference numerals 1 </ b> A and 1 </ b> B denote magnetic pole plates arranged in parallel with the permanent magnet 2 interposed therebetween, and are excited by the permanent magnet 2 to the N and S poles. A crucible 4 in which the evaporating substance 3 is accommodated is provided between the magnetic pole plates. An electron gun 5 is provided under the crucible.

  The electron gun includes a filament 6, a grid 7 and an anode 8 as cathodes. 9 is a filament heating power source, and 10 is an acceleration power source. Reference numeral 11 denotes a grid support plate, and the filament 6 is attached to the grid support plate.

  Reference numeral 13 denotes a scanning electromagnetic coil body in which an X-direction scanning deflection coil and a Y-direction scanning deflection coil are wound around an annular iron core, which is disposed on the electron beam path from the electron gun 5. The scanning electromagnetic coil body 13 is supported by, for example, a non-magnetic holder (not shown) attached near the crucible 4 between the magnetic poles 1A and 1B. Reference numeral 14 denotes a scanning power source for causing a scanning current to flow through the scanning electromagnetic coil body 13.

  In such an electron beam evaporation apparatus, the electron beam generated from the filament 6 of the electron gun 5 is accelerated by the anode 8 while being focused by the grid 7, and is 270 ° by the magnetic field generated by the magnetic poles 1A and 1B. The evaporating substance 3 which is bent back and forth and accommodated in the crucible 4 is irradiated. At this time, since the electron beam from the electron gun 5 passes through the two-dimensional scanning magnetic field generated by the scanning electromagnetic coil body 13, the electron beam scans the evaporation material 3 in the two-dimensional direction. Become. As a result, the evaporated substance is heated and evaporated by the electron beam, and the evaporated particles adhere to the substrate (not shown) disposed above the crucible 4 in a film form, for example.

  As the filament 6 of the electron gun 5 that evaporates the evaporating substance 3 by electron irradiation as described above, a large one is generally used so that a high-power beam (a beam with a large beam current) can be obtained at a low voltage. Yes. For example, a spiral shape as shown in FIG.

  However, when the evaporating substance 3 is evaporated by electron beam irradiation, a part of the vapor is ionized by the impact of the electron beam. Usually, the evaporating material is a metal, so these ions are positive ions. These positive ions are a negative potential filament 6 along the central axis O of the deflection trajectory (substantially a conductor) 15 of the electron beam between the filament 6 and the evaporated substance 3 in the crucible 4. Head for. These positive ions hit the central portion of the filament 6 and sputter the portion.

For this reason, since the portion is gradually thinned, excessive Joule heat is generated in the portion, the wire is eventually broken, and the filament must be replaced with a new one.
When such fusing occurs during the vapor deposition operation, the deposited film becomes not only defective, but filament replacement by such fusing is extremely disadvantageous both economically and operationally. Furthermore, when such fusing occurs in a short time, it becomes a very big problem.

  Therefore, for example, as shown in FIG. 3 (b), a filament 60 having a vacant center portion (a portion corresponding to K in FIG. 3) or a coiled filament as shown in FIG. 3 (c) is formed in an annular shape. If 600 is used, such a problem can be solved.

Japanese Patent No. 3814114

  For example, when depositing a film of a compound such as an oxide on a substrate, oxygen gas is used as a process gas in a vacuum chamber in which the crucible 4, the electron gun 5, and the substrate (not shown) are accommodated. A large quantity is supplied.

  Of course, such oxygen gas also enters the periphery of the filament 6 of the electron gun 5, so that the filament causes a chemical reaction with the gas, and an oxide having a high vapor pressure is generated on the filament surface. The portion of the filament including the electron emission surface (so-called electron emission portion) is consumed by evaporation of the oxide, and the filament itself is disconnected in a short time.

  Therefore, in order to solve the above-mentioned problem, as the filament, a spiral-shaped one having a vacant center as shown in FIG. 3 (a) or a coil-shaped filament as shown in FIG. 3 (b) formed in an annular shape. However, when a film of a compound such as an oxide is deposited on the substrate, it is inevitable that the filament itself is disconnected in a short time due to consumption of the electron emission portion.

  The present invention has been made to solve such problems, and an object of the present invention is to provide an electron beam apparatus capable of suppressing the consumption of the cathode and extending the lifetime.

  An electron beam apparatus of the present invention includes a cathode in which an electron emission portion is disposed so as to surround a central space portion, an opening through which electrons generated from the cathode pass, and a grid disposed to face the cathode, An opening having electrons passing through the grid, the anode disposed opposite to the grid, and ions passing through the opening of the grid and flying toward the cathode impact in the space of the cathode Alternatively, a metal member having a tip surface disposed between the cathode and the grid or on the rear side of the space portion when viewed from the anode is provided.

  According to the present invention, the process gas existing around the cathode of the electron gun can be reduced, and the progress of consumption due to oxidation of the cathode can be remarkably suppressed, so that the life of the cathode can be significantly prolonged. I can do it.

As an example of an electron beam apparatus, an outline of an electron beam evaporation apparatus is shown. It is the sectional view on the AA line of FIG. A schematic example of a filament is shown. 1 schematically shows an electron beam evaporation apparatus which is an example of an electron beam apparatus according to the present invention. It is the figure used for description of operation | movement of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 4 shows an outline of an electron beam evaporation apparatus which is an example of the electron beam apparatus of the present invention. In the figure, the same reference numerals as those used in FIG. 2 denote the same components.

  In this example, as the cathode, a spiral filament 60 having a vacant central portion as shown in FIG. 3B or a ring-shaped one 600 having a coiled filament as shown in FIG. 3C is used. Although being used, the cathode is not limited to a filament, and various cathodes can be used as long as they have a plate-like or rod-like heating element that does not have a heating element in the central portion.

  In the drawing, reference numeral 20 denotes a central hole O of the electron beam deflection orbit 15, a central hole of the anode 8, a central hole of the grid 7, and a portion (referred to as an electron gun central axis) O in the central space of the filament 60 ′. 'Is a cylindrical ion collector attached to the grid support plate 11 so that its tip surface is located in the central space of the filament 60'.

  The ion collector is made of a metal material having a strong getter action, such as titanium.

  In the figure, reference numeral 21 denotes a metal plate (for example, non-magnetic, heat-resistant and oxidation-resistant such as stainless copper) disposed on the extended line of the electron gun central axis O ′ opposite to the ion collector 20 when viewed from the anode 8. The metal plate is grounded.

  In such an electron beam evaporation apparatus, when a film of a compound such as an oxide is deposited on the substrate, the inside of the vacuum chamber in which the crucible 4, the electron gun 5, the substrate (not shown), etc. are housed. Is supplied with oxygen gas as a process gas.

  In such a situation, the electron beam generated from the filament 6 of the electron gun 5 is accelerated by the anode 8 while being focused by the grid 7, and is bent around 270 ° by the magnetic field generated by the magnetic poles 1A and 1B. The evaporating substance 3 accommodated in the crucible 4 is irradiated. At this time, since the electron beam from the electron gun 5 passes through the two-dimensional scanning magnetic field generated by the scanning electromagnetic coil body 13, the electron beam scans the evaporation material 3 in the two-dimensional direction. Become. As a result, the evaporated substance is heated by an electron beam to evaporate, and the evaporated particles react with the oxygen gas. For example, an oxygen compound is formed on a substrate (not shown) disposed above the crucible 4. Adhere to a film.

  When actually forming such an oxygen compound film, for example, a high-frequency coil to which high-frequency power is applied is disposed between a substrate (not shown) and the crucible 4, and the periphery of the high-frequency coil is arranged. A plasma of the evaporated particles and oxygen particles is generated by a high-frequency electric field generated in the part, and an oxide film is formed on the substrate. In this manner, when a film is formed on a substrate in a state where plasma is generated, a high-quality oxide film having high density and high adhesion to the substrate can be formed.

  Now, in the formation of such an oxide film, the oxygen gas supplied into the vacuum chamber also enters the periphery of the filament 60 ′ of the electron gun 5.

  At this time, when the evaporating substance 3 evaporates by electron beam irradiation, a part of the vapor is ionized (positive ionization) by the impact of the electron beam, and the positive ions are centered on the deflection trajectory 15 of the electron beam from the filament 60 ′. Along the O, it goes to the filament 60 'having a negative potential, passes through the central space of the filament, hits the tip surface of the ion collector 20, and sputters the tip surface.

  Then, titanium particles jump out of the tip surface of the ion collector, and the titanium particles reach the surface of the grid 7, reach the surface of the anode 8, or move along the electron gun center axis O ′. It passes through the center space, the center hole of the grid, and the center hole of the anode 8 in this order to reach the surface of the metal plate 21, and on the filament side surface of the grid 7 and the filament side surface of the anode 8. A titanium deposition layer TDL is formed on the top and the surface of the metal plate 21.

Then, on the surface of each titanium deposition layer TDL, oxygen gas existing around the grid 7 and the anode 8 including the filament 60 ′ is caused to be in contact with the titanium by the getter action (the action of chemically adsorbing the gas) of titanium. A compound (for example, TiO ₂ ) is generated by the reaction, and is adsorbed on the titanium deposition layer TDL.

  As described above, since the oxygen gas existing around the electron gun 5 is adsorbed to the titanium deposition layer TDL, the oxygen gas concentration around the filament 60 'becomes extremely dilute, and as a result, the filament and oxygen gas The chemical reaction is remarkably suppressed, and consumption due to oxidation of the electron emission portion of the filament is suppressed.

  Note that the tip surface of the ion collector 20 is sputtered, and in addition to the ionized vaporized particles of the vaporized substance 3, the gas remaining around the electron gun 5 is ionized by electron impact from the filament 60 '. There is.

  In the above embodiment, the present invention is applied to the case where the oxidation of the filament by oxygen existing around the filament is suppressed. However, an inert gas such as argon for generating plasma in the vacuum chamber or the like When a reactive gas other than oxygen is introduced and the gas enters the periphery of the electron gun and there is a risk of generating an arc discharge between the anode and the grid of the electron gun to which a high electric field is applied, Inert gas or reactive gas is trapped in each titanium deposition layer TDL formed on the surface of the grid 7, the surface of the anode 8, and the surface of the metal plate 21, and the discharge is suppressed by locally lowering the gas pressure. It can also be applied to.

  In the above example, the case where titanium is used as the material of the ion collector 20 has been described. However, a getter material having a strong getter action, an alloy mainly composed of titanium, tantalum, an alloy mainly composed of tantalum, zirconium. Alternatively, an alloy containing zirconium as a main component, barium, an alloy containing barium as a main component, magnesium, an alloy containing magnesium as a main component, or the like may be used.

In the above example, the ion collector 20 is attached to the grid support plate 11 so that the tip surface of the ion collector 20 is located in the center space of the filament 60 '. You may attach to this grid support plate so that it may be located in the grid support plate side, and you may attach to this grid support plate so that a front end surface may be located in the grid 7 side rather than the center part space of this filament. However, when mounting so as to be positioned on the grid side, the focusing property of the electrons from the filament 60 ′ by the grid 7 is reduced. Need to be low.
In the above example, the metal plate 21 is disposed on the extension of the electron gun central axis O ′ opposite to the ion collector 20. However, instead of the metal plate 21, You may utilize the inner wall (metal) in an electron beam vapor deposition apparatus.

1A, 1B ... pole plate 2 ... permanent magnet 3 ... evaporative substance 4 ... crucible 5 ... electron gun 6, 60, 60 ', 600 ... filament 7 ... grid 8 Anode 9 ... Filament heating power supply 10 ... Acceleration power supply 11 ... Grid support plate 13 ... Scanning electromagnetic coil body 14 ... Scanning power supply 15 ... Electron beam deflection orbit 20 .... Ion collector 21 ... Metal plate O ... Electronic beam deflection orbit center axis O '... Electron gun center axis

Claims (3)

A cathode having an electron emission portion disposed so as to surround a central space portion, an opening for allowing electrons generated from the cathode to pass therethrough, a grid disposed to face the cathode, and electrons having passed through the grid are allowed to pass. An anode having an opening and disposed opposite to the grid; and a space in the cathode or between the cathode and the grid so that ions flying through the opening of the grid and flying toward the cathode are bombarded. An electron beam apparatus comprising a metal member having a distal end face disposed in the middle or behind the space portion as viewed from the anode. 2. The electron beam apparatus according to claim 1, wherein the metal member is made of a metal having a large getter action. The metal member is mainly titanium, an alloy containing titanium as a main component, tantalum, an alloy containing tantalum as a main component, zirconium, an alloy containing zirconium as a main component, barium, an alloy containing barium as a main component, magnesium, or magnesium. 3. The electron beam apparatus according to claim 2, wherein the electron beam apparatus is an alloy as a component.

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