JP2001262321A - Evaporating source in vacuum vapor deposition apparatus, and heating method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an evaporating source in a vacuum vapor deposition apparatus, and a heating method thereof. SOLUTION: The evaporating source in the vacuum vapor deposition apparatus to efficiently heat the evaporating source comprises an evaporating source container formed of a conductive substance having a high melting point, an evaporating source supporting metal bar to support the container, a heater formed of a metal foil having a high melting point disposed below the evaporating source container, a heater power source to energize the heater, and an electron acceleration power source to apply to power between the evaporating source container and the heater. In the heating method using the evaporating source, the metal foil having a high melting point is energized and heated, the evaporating source container is radiated and heated by the radiation heat therefrom, the voltage is applied between the evaporating source container and the heater to a accelerate the electrons emitted from the surface of the metal foil and allow the evaporating source container irradiated therewith, and the vacuum evaporating source is efficiently heated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for more efficiently heating an evaporation source in a vacuum evaporation apparatus for coating the surface of various materials, and more particularly, to a vacuum evaporation apparatus. The present invention relates to an evaporation source capable of heating an evaporation source therein more efficiently and enabling a simple design of an apparatus, and a heating method thereof.

[0002]

2. Description of the Related Art Conventionally, various methods have been developed as a vacuum deposition method for forming a thin film by coating the surface of various materials. The following is a list of conventional methods for producing the thin film. (1) Electric heating type evaporation method In this method, a heater made of tungsten, molybdenum, or the like is used, and the heater itself is used as an evaporation source container. This method is the simplest method for heating the evaporation source, but usually requires a large current power supply of 50 A or more due to the limitation of the shape of the evaporation source container. In addition, a large electrode must be used to withstand a large current for conducting a large current into a vacuum, which limits the miniaturization of the apparatus. (2) Electron Beam Heating Deposition Method In this method, an evaporation source is directly irradiated with an electron beam of several keV obtained from an electron gun. This method is an efficient method of heating the evaporation source, but requires several kilograms to create an electron beam.
In order to apply a voltage of V to an electrode in a vacuum and guide an electron beam to an evaporation source, it is necessary to use a component such as a permanent magnet in a vacuum. (3) Other vapor deposition methods In addition to the above, sputtering, ion plating, C
Although the VD method and the like are conceivable, these methods are limited in terms of downsizing of the apparatus, and a detailed description is omitted from the viewpoint of simplicity of the apparatus. As described above, conventionally, as the heating method of the evaporation source in the vacuum evaporation apparatus, the above-described heating method has been developed. However, any method has a problem to be improved in order to simplify the entire apparatus. .

[0003]

DISCLOSURE OF THE INVENTION The present inventors have conducted "research on technology for measuring dynamic behavior of light elements in solids by fast neutrons" in nuclear test research at national organizations. In this research, it was necessary to prepare a target thin film such as lithium or titanium deuteride for generating neutrons by irradiating a high energy ion beam. Initially, the target was produced using an existing vacuum deposition apparatus. However, as the experiment progressed, it became clear that the target thin film was preferably produced around the high energy ion irradiation apparatus. In order to meet this demand, a portable and simple vacuum deposition apparatus was designed.At this stage, (1) avoid using a large current exceeding 50 A as in the current-carrying heating method, (2) ) Use of high voltage exceeding 1 kV as in the electron beam heating method and avoiding the use of permanent magnets, etc. (3) This enables efficient heating of the evaporation source that can simplify the entire apparatus As a result, the present inventors have succeeded in developing a new evaporation source having a simple mechanism and a heating method thereof, and have completed the present invention. That is, an object of the present invention is to develop and provide an evaporation source that more efficiently heats an evaporation source in a vacuum evaporation apparatus and enables a simple design of the apparatus.

[0004]

The present invention for solving the above-mentioned problems comprises the following technical means. (1) An evaporation source for efficiently heating an evaporation source in a vacuum evaporation apparatus, comprising: an evaporation source container made of a conductive high melting point material; and a metal evaporation source supporting the container. It comprises a rod, a heater for heating made of a high melting point metal foil disposed under the evaporation source container, a heater power supply for supplying electricity to the heater, and an electron accelerating power supply for application between the evaporation source container and the heater. The high-melting point metal foil is electrically heated, and the evaporation source container is radiatively heated by radiant heat therefrom, and a voltage is applied between the evaporation source container and the heater to accelerate electrons emitted from the metal foil surface. The evaporation source is configured to irradiate the evaporation source container to heat the vacuum evaporation source efficiently. (2) The evaporation source according to the above (1), wherein a part of the surface of the metal foil is coated with a different substance to enhance the local emission efficiency of thermoelectrons. (3) A method of heating the evaporation source using the evaporation source according to the above (1) or (2), wherein the high melting point metal foil is electrically heated, and the evaporation source container is radiated by the radiant heat. At the same time, a voltage is applied between the evaporation source container and the heater, the electrons emitted from the surface of the metal foil are accelerated and irradiated to the evaporation source container, and the vacuum evaporation source is heated. Method.

[0005]

Next, the present invention will be described in more detail. The present invention employs, as a vapor deposition method, a method in which a small evaporation source container made of a high melting point material is used, and heating is performed by a heater disposed at a lower portion of the evaporation source container by two types of heat radiation and electron beam impact. The evaporation source is a small container made of a conductive high-melting substance, and has a shape capable of performing radiant heating and electron beam impact heating. Examples of the conductive high melting point material include graphite, tungsten, molybdenum, tantalum, and silicon carbide. The shape of the container is exemplified by a cylindrical container or a rectangular cylindrical container. The evaporation source is
In order to minimize heat radiation due to heat conduction, it is supported by a thin metal support rod or the like. Several meters as heater for heating
A thin, high melting point metal foil having a width of about m is arranged below the evaporation source container. Examples of the metal foil include tungsten, molybdenum, graphite, and tantalum. The thickness of the metal foil is 50 μm or less, a width of 2 to 10 mm, and a length of 20 μm.
~ 50 mm is preferred. The evaporation source container is radiatively heated by electrically heating the heater. A high voltage of several hundred volts is applied between the evaporation source container and the heater to accelerate the thermoelectrons emitted from the heater to heat the evaporation source container. In this case, a power supply having a high voltage of 300 to 800 V and a current capacity of 1 to 5 A is used. It is desirable that the thermoelectron emission portion on the heater surface be coated with a different substance to improve the efficiency of thermoelectron emission. Dissimilar substances include tungsten with thorium, which has a high melting point and a low work function.
Examples include lanthanum boride, calcium oxide, barium oxide, molybdenum, and zirconium. As a method for coating this different substance, a sputtering method is preferable.
At 〜100 nm, the area is comparable to the bottom of the evaporation source container.

According to the present invention, as described above, (1) using a high melting point metal foil such as tungsten as a heat source and an electron beam source, (2) using a high melting point evaporation source container having a small heat capacity, (3) The electron emission portion of the heater is coated with a different kind of substance to improve the electron generation efficiency. As described above, the present invention provides an evaporation source having a simple mechanism and a heating method thereof. In the present invention,
Efficient use of both the radiant heating effect of energizing and heating the thin refractory metal foil in vacuum and the electron beam heating effect obtained by accelerating and impacting the emitted thermoelectrons with an electric field The heating of the vacuum evaporation source can be realized. In addition, by covering a part of the surface of the metal foil with a different kind of substance, the efficiency of generating thermoelectrons can be improved.

[0007]

EXAMPLES The present invention will be described more specifically based on examples, but the present invention is not limited to the following examples. Embodiment FIG. 1 shows the structure of the evaporation source of the present invention, that is, the arrangement of the heater for evaporation and the evaporation source container and the electrical connection diagram. As the high melting point metal heater, a rectangular tungsten foil of 50 mm × 5 mm × 0.05 mm was used. The evaporation source container has an outer diameter of 25.
mm, a height of 15 mm, and a wall thickness of about 1 mm. A current of up to 40 A was passed through the heater, and a voltage of up to 500 V was applied between the heater and the evaporation source container placed 10 mm above. Molybdenum was coated to a thickness of about 1 nm by an ion beam sputtering method in an area of about 25 mm 2 at the center of the heater. Thereby, the electron emission efficiency of the coated portion was improved to about 2 to 5 times. According to the above method, the heater power is about 1500 W (50 V, 30 A),
The graphite evaporation source container could be heated up to 1500 ° C. with an electron beam heating power of 300 W (600 V, 0.5 A).

The above result is an example of the present invention, and the present invention further has the following features. (1) The heater current can be reduced by setting the thickness of the heater foil to 0.05 mm or less. (2) The heat capacity of the evaporation source container can be reduced. (3) By increasing the acceleration voltage by several hundred volts, electron beam heating power can be increased by several tens of percent. (4) Materials other than molybdenum may be
Tungsten-containing tungsten, lanthanum boride, calcium oxide, barium oxide, and zirconium are used, whereby a more efficient thermionic emission surface can be formed. In view of the above, the present invention makes it possible to design a simple vacuum evaporation apparatus that can realize an evaporation source that can be heated to 1500 ° C. or higher.

[0009]

According to the present invention, 1) the heater heating current can be reduced to 50 A or less, and the electron beam acceleration power supply voltage can be reduced to 1 KV or less (several A). 2) The simplification of the evaporation source and related parts that require high-temperature heating, It is possible to obtain effects such as simplification, 3) downsizing of the device and reduction of cost.

[Brief description of the drawings]

FIG. 1 shows an arrangement and a cross-sectional view of an electron beam source heater and a deposition crucible, and a power supply connection diagram.

Claims (3)

[Claims] 1. An evaporation source for efficiently heating an evaporation source in a vacuum evaporation apparatus, comprising: an evaporation source container made of a conductive high-melting substance; and a metal evaporation supporting the container. A source support rod, a heater for heating made of a high melting point metal foil disposed under the evaporation source container, a heater power supply for supplying electricity to the heater, and an electron acceleration power supply for applying between the evaporation source container and the heater are provided as constituent elements. The above-mentioned high melting point metal foil is electrically heated, and the evaporation source container is radiatively heated by radiant heat from this, and a voltage is applied between the evaporation source container and the heater to generate electrons emitted from the metal foil surface. An evaporation source characterized in that it is configured to accelerate and irradiate an evaporation source container to efficiently heat a vacuum evaporation source. 2. The evaporation source according to claim 1, wherein a part of the surface of the metal foil is coated with a different kind of material to enhance the local emission efficiency of thermoelectrons. 3. Use of the evaporation source according to claim 1 or 2,
A method of heating an evaporation source, in which a high-melting-point metal foil is electrically heated, a radiation heat is applied to the evaporation source container by radiant heat, and a voltage is applied between the evaporation source container and the heater, and the surface of the metal foil is heated. A method for heating an evaporation source, comprising: irradiating the evaporation source container with accelerated electrons emitted from a vacuum evaporation source and heating the vacuum evaporation source.