JP2002361070A - Vacuum equipment made of aluminum alloy and driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain vacuum equipment made of an aluminum alloy which is high in the rate of evacuation. SOLUTION: This vacuum equipment made of the aluminum alloy has a vacuum vessel 3 made of the aluminum alloy formed with a negative electrode which is packed into the micropores of an anodically oxidized film 33 formed on the vacuum side surface of the vacuum vessel and releases electrons by electric field radiation and an extraction electrode disposed on the surface of the anodically oxidized film, a terminal 41 for the negative electrode for impressing a voltage to the negative electrode, a terminal 42 for the extraction electrode for impressing the voltage to the extraction electrode, a driving power source 61 for impressing the voltage to both poles of the negative electrode and the extraction electrode, an ion electrode 5 which is disposed near an air exit and promotes the evacuation of the ions and a power source 62 for the ion power source for impressing the voltage to the ion electrode. The voltage to be impressed to the ion electrode is a low-frequency voltage of <=5 Hz and the waveform thereof is formed of a sinusoidal wave or pulse wave.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum apparatus used in a vacuum heat treatment furnace, various analyzers, accelerators, semiconductor manufacturing apparatuses, and the like. Related to the device.

[0002]

2. Description of the Related Art Conventionally, a vacuum apparatus as shown in FIG. 6 has been proposed as a vacuum apparatus for improving the efficiency of an exhaust function (Japanese Patent Laid-Open No. 10-228880). FIG. 6 is a perspective view of a cross section showing a conventional aluminum alloy vacuum device. In the figure, 1 is a base, 2 is an insulator, and 3 is a vacuum vessel made of an aluminum alloy. The aluminum alloy vacuum vessel 3 is made of an aluminum alloy base 31, and the inner and outer peripheral surfaces are anodized to form anodized films 33 and 34. FIG. 7 shows an enlarged view of the anodic oxide film 33 (part A in FIG. 6) applied on the vacuum side. The anodic oxide film 33 is formed on the vacuum side of the barrier layer 32 on the vacuum side of the substrate 31. In the micropores 35 existing in the anodic oxide film 33,
Metallic iron is deposited as an electrode material for performing field emission and used as the negative electrode 36. Further, on the vacuum side of the anodic oxide film 33, a conductive extraction electrode 37 is provided on the entire surface. The extraction electrode 37 extracts electrons emitted from the negative electrode 36. A negative electrode terminal 41 for applying a voltage to the negative electrode 36 and a lead electrode terminal 42 are provided. The lead electrode terminal 42 is provided insulated from the base 31 and the like. The negative electrode terminal 41 and the extraction electrode terminal 42 are connected to a drive power supply 61 so that a potential can be applied. Further, an ion electrode 5 for ion collection is arranged near the exhaust port in the aluminum alloy vacuum vessel 3 and a power supply 62 for the ion electrode for driving the ion electrode.
Has been arranged. Next, the operation will be described. First, after the inside of the aluminum alloy vacuum vessel 3 is evacuated, a drive voltage (DC) shown in FIG. 8 is applied from the drive power supply 61 to the negative electrode terminal 41 and the extraction electrode terminal 42. Then, the electrons emitted from the negative electrode 36 are extracted from the extraction electrode 37 and collide with the remaining gas to ionize the remaining gas. Almost at the same time, the DC voltage shown in FIG. 9 is applied to the ion electrode 5 from the ion electrode power supply 62. The ionized residual gas is guided to the ion electrode 5 by the force of the electric field, accelerates the exhaust, and increases the degree of vacuum.

[0003]

However, when the emitted electrons collide with the residual gas to be ionized, for example, hydrogen gas becomes positive and oxygen gas becomes negative, and bipolar ions are present. Then, if only one polarity is used, one ion cannot be efficiently exhausted, and it takes time to exhaust. Further, even if a vacuum vessel is set and the chamber is evacuated to vacuum and a voltage is applied to the negative electrode, only a few electrons are emitted at the beginning of the voltage application. This is because the gas adsorbed on the tip of the negative electrode does not easily escape. Since it takes time to emit electrons, it takes time to exhaust.
When the barrier layer is sufficiently thick, the MIM (Metal-In
(sulator-Metal) structure, so that only a very small amount of current can be obtained. In order to obtain a sufficient current, the extraction voltage must be extremely high, and the practicality is extremely narrow. Therefore, the present invention provides an aluminum alloy vacuum device having a high pumping speed by devising a method of applying voltage to the negative electrode, the extraction electrode and the ion electrode, and devising a layer structure near the negative electrode. With the goal.

[0004]

To solve the above problems, the present invention has the following arrangement. (1) A negative electrode that fills the micropores of the anodic oxide film formed on the vacuum side surface of the vacuum vessel and emits electrons by electric field radiation, and an extraction electrode provided on the surface of the anodic oxide film are formed. A vacuum vessel made of an aluminum alloy, a negative electrode terminal for applying a voltage to the negative electrode, an extraction electrode terminal for applying a voltage to the extraction electrode, and a drive power supply for applying a voltage to both the negative electrode and the extraction electrode In an aluminum alloy vacuum device comprising: an ion electrode provided in the vicinity of an exhaust port for promoting the exhaustion of ions, and a power supply for an ion electrode for applying a voltage to the ion electrode, wherein the power supply for the ion electrode is It has a function of generating a sine wave or pulse wave with a low frequency voltage of 5 Hz or less and a waveform thereof. (2) The thickness of the barrier layer between the negative electrode and the negative electrode terminal is 10 nm or less. (3) The driving power supply has a function of generating a pulse voltage within 50 ms and a voltage of 300 V or more. (4) A negative electrode which fills the micropores of the anodic oxide film formed on the vacuum side surface of the vacuum vessel and emits electrons by electric field radiation, and an extraction electrode provided on the surface of the anodic oxide film are formed. An aluminum alloy vacuum vessel, a negative electrode terminal for applying a voltage to the negative electrode, an extraction electrode terminal for applying a voltage to the extraction electrode, and applying a voltage to both the negative electrode and the extraction electrode. A driving power supply, and driving of an aluminum alloy vacuum device that evacuates the aluminum alloy vacuum vessel and applies a negative voltage between the negative electrode terminal and the extraction electrode terminal to increase the degree of vacuum. In the method, the voltage applied between the negative electrode terminal and the extraction electrode terminal is such that a pulsed voltage of 300 V or more is applied at least once within 50 ms, and then a steady low voltage is applied. It applies an pressure. (5) An ion electrode for promoting ion exhaustion is provided near the exhaust port, and a low frequency voltage of 5 Hz or less and a sine wave or pulse wave is applied to the ion electrode. is there. According to this configuration, by applying a low-frequency voltage of 5 Hz or less, ionized gas molecules to be evacuated with positive or negative charges can be efficiently collected on the electrode near the exhaust hole. Frequency is more important than waveform. Usually, a suction force by a vacuum pump and an electric field force by an ion electrode are added.
When a direct current is applied to the electrodes, the pumping speed is governed by the movement of ions that receive opposing electric forces. Therefore, if an AC voltage is applied, both positively and negatively charged ions are exhausted. Further, by applying a pulsed voltage first, the gas adsorbed on the negative electrode can be blown off, so that a predetermined amount of electrons is emitted from the beginning of the exhaust. Further, by making the barrier layer in contact with the negative electrode terminal extremely thin, the amount of emitted electrons increases, so that the molecular weight of ionized gas to be exhausted increases, and more gas adsorbed on the negative electrode can be blown off. And the exhaust is faster.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings shown in the embodiments. (First Embodiment) FIG. 1 shows a first embodiment of the present invention. FIG.
1 is a perspective view of a vacuum apparatus made of an aluminum alloy according to a first embodiment of the present invention as viewed from a cross section. In the figure, 31 is a substrate, 33 is an anodized film (vacuum side), 34 is an anodized film (atmospheric side), 35 is a fine hole, 36 is a negative electrode, and 37 is an extraction electrode. Also, 41 is a negative electrode terminal, 42 is an extraction electrode terminal, 5 is an ion electrode, 61 is a drive power source, 6
Reference numeral 2 denotes a power supply for the ion electrode. The vacuum vessel 3 made of an aluminum alloy includes an anodized film 33 on the vacuum side and an anodized film 34 on the atmosphere side. The other reference numerals are the same as those of the components described in the related art, and the description thereof is omitted. The base 31 of the aluminum alloy vacuum vessel 3 is made of duralumin, and the inner and outer peripheral surfaces are anodized. In the fine holes 35 of the anodic oxide film 33 formed on the inner peripheral surface, metallic iron is deposited as an electrode material for emitting electric field. The thickness of the alumite layer was 10 μm, and the diameter of the micropores was 300 Å. Next, the anodic oxide film 33 on the inner peripheral surface
An aluminum film was formed as a lead electrode 37 by wire explosion spraying in vacuum. The vacuum vessel 3 made of the aluminum alloy manufactured in this manner is arranged on the insulator 2 provided on the gantry 1 to assemble a vacuum pumping apparatus, and an ion capable of applying a low-frequency AC voltage to the ion electrode 5. The electrode power supply 62 was connected. Note that a rotary pump and a turbo molecular pump were used as the exhaust pump. Next, the operation and effects of the aluminum alloy vacuum device of the present invention will be described. (1) First, the inside of the vacuum vessel was evacuated with a rotary pump. (2) Next, between the extraction electrode 37 and the negative electrode 32, 60
A potential of V was applied, and an evacuation operation was performed. When a voltage is applied to the negative electrode 36, electrons are emitted from the negative electrode 36, Joule heat is generated by the current flowing at this time, and the vacuum vessel is heated to perform baking. At the same time, when a voltage is applied to the extraction electrode 37, electrons emitted from the negative electrode 36 are extracted, so that a current easily flows and exhaust is promoted. (3) 5H as shown in FIG. 2 is applied to the ion electrode 5 near the exhaust port.
z, 600 V low frequency sine wave is supplied to the ion electrode power source 62.
Added from. For comparison, a conventional case where the above-described AC voltage was not applied to the ion electrode 5 was also examined. The result is shown in FIG.
The evacuation time to reach the target pressure is several times faster in the present embodiment than in the conventional example, and it can be seen that there is an excellent effect. This is because, when a low-frequency voltage is applied to the ion electrode 5, gas molecules ionized by the generated electrons are easily collected, so that a high vacuum can be obtained in a short time. If the frequency is higher than this value, ions moving toward the electrode change polarity and move in a direction other than the electrode, so that ions cannot be collected efficiently.

(Second Embodiment) A second embodiment of the present invention will be described. The specifications such as the structure of the aluminum alloy vacuum apparatus of the present embodiment are the same as those of the first embodiment. The operation and effect of the aluminum alloy vacuum device of the present invention will be described. (1) First, the inside of the vacuum vessel was evacuated with a rotary pump. (2) Next, between the extraction electrode 37 and the negative electrode 32, FIG.
A 60 V potential was applied as shown in FIG. (3) A low frequency pulse wave of 5 Hz and 600 V was applied to the ion electrode 5 near the exhaust port. FIG. 4 shows the state of the voltage applied to the ion electrode 5. For comparison, a case where the above-described AC voltage was not applied to the ion electrode 5 was examined. As a result, it was found that the pumping speed was several times faster than that of the conventional example, which is a good result, as in the first embodiment. (Third Embodiment) A third embodiment of the present invention will be described.
The structure of the vacuum device of the present embodiment is the same as that of the first embodiment in both the appearance and the sectional structure. The operation and effect of the aluminum alloy vacuum device of the present invention will be described. (1) First, the inside of the vacuum vessel was evacuated with a rotary pump. (2) 600 V was applied to the ion electrode 5 near the exhaust port. (3) Next, at the beginning of use, a pulse-like voltage of -300 V as shown in FIG.
ms maintenance was performed twice. Thereby, the gas molecules adsorbed in the fine holes 35 are impacted, so that the adsorption can be separated. In this case, the voltage is -300 V or more,
It is necessary to apply a pulse voltage of 0 ms or less, but if the application time of the voltage is lengthened, the negative electrode melts and evaporates. (4) Thereafter, a steady potential of 60 V was applied to perform an exhaust operation. As a result, it was found that the pumping speed was several times faster than that of the conventional example, which is a good result, as in the first embodiment. In this embodiment, one power supply has two functions, but power supplies having different functions may be provided. (Fourth Embodiment) A fourth embodiment of the present invention will be described.
The structure of the vacuum device of the present embodiment is the same as that of the first embodiment in both the appearance and the sectional structure. The difference is that the thickness of the barrier layer 32 is extremely thin, 10 nm. For comparison, a substrate having a conventional barrier layer having a thickness of 100 nm was prepared. The operation was performed by exhaust driving in the same manner as in the first embodiment, and the exhaust characteristics were compared. As a result, it was found that the pump of the present embodiment improved the pumping speed by about 10 times compared to the conventional pump, which was a good result. (Fifth Embodiment) A fifth embodiment of the present invention will be described.
The structure of the vacuum device of the present embodiment is the same as that of the first embodiment in both the appearance and the sectional structure. The difference is that the thickness of the barrier layer 32 is further reduced to 1 nm or less. For comparison, a substrate having a conventional barrier layer having a thickness of 100 nm was prepared. In the operation, the exhaust driving was performed as in the second embodiment, and the exhaust characteristics were compared. As a result, it was found that the pump of the present invention improved the pumping speed by about 70 times as compared with the conventional pump, which was a good result.

[0007]

As described above, according to the present invention, since a low-frequency AC voltage of 5 Hz or less is applied to the ion electrode provided in the vicinity of the exhaust port, the exhaust gas having a positive or negative charge is applied. The ionized gas molecules to be collected can be efficiently collected on the electrode near the exhaust port. Therefore, there is an effect that the pumping speed of the vacuum device can be significantly improved. Further, since a pulse-like voltage is applied between the extraction electrode and the negative electrode at the beginning of use, gas adhering to the negative electrode can be blown out. Therefore, a predetermined amount of electrons is emitted from the beginning of the exhaust, and the probability of collision between the gas and the electrons increases from the start of use to promote ionization. Since the gas is quickly exhausted by the electric field of the electrode provided at the exhaust port, there is an effect of obtaining an aluminum alloy vacuum device capable of obtaining an ultra-high vacuum in a short time. Further, by setting the barrier layer between the cathode and the cathode terminal for applying a voltage to the cathode to 10 nm or less, the amount of electrons emitted from the cathode increases, so that the ionized gas molecules to be exhausted increase. In addition, the gas attached to the negative electrode can be sufficiently blown, and the evacuation speed of the vacuum device can be further remarkably improved.

[Brief description of the drawings]

FIG. 1 is a perspective view of a cross section of an aluminum alloy vacuum device showing a first embodiment of the present invention.

FIG. 2 is a graph showing a voltage waveform applied to the ion electrode of the first embodiment.

FIG. 3 is a graph showing the exhaust characteristics of the first embodiment.

FIG. 4 is a graph showing a voltage waveform applied to an ion electrode of a second embodiment.

FIG. 5 is a graph showing a voltage waveform applied between an extraction electrode and a negative electrode according to the third embodiment.

FIG. 6 is a perspective view of a cross section showing a conventional aluminum alloy vacuum device.

FIG. 7 is an enlarged schematic view of a negative electrode portion of a vacuum container made of an aluminum alloy.

FIG. 8 is a graph showing a conventional voltage waveform applied between an extraction electrode and a negative electrode.

FIG. 9 is a graph showing a voltage waveform applied to a conventional ion electrode.

[Explanation of symbols]

1: Mount 36: Negative electrode 2: Insulator 37: Extraction electrode 3: Aluminum alloy vacuum vessel 41: Negative electrode terminal 31: Base 42: Extraction electrode terminal 32: Barrier layer 5: Ion electrode 33: Anodized film (Vacuum side) 61: Drive power supply 34: Anodized film (atmosphere side) 62: Power supply for ion electrode 35: Micropore

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01J 41/18 H01J 41/18 H05H 7/14 H05H 7/14 (72) Inventor Nobuhiko Ota Kitakyushu, Fukuoka Yasukawa Denki Co., Ltd. 2-1 Kurosaki Shiroishi, Yawata Nishi-ku (72) Inventor Shinji Shinbe 2-1, Kurosaki Shiroishi, Yawata Nishi-ku, Kitakyushu-shi, Fukuoka F-term (reference) 2G085 BA05 BD06 5C038 AA02 AA03 AA05 AA12

Claims (5)

[Claims] 1. A negative electrode which is filled in micropores of an anodic oxide film formed on the vacuum side surface of a vacuum vessel and emits electrons by electric field radiation, and an extraction electrode provided on the surface of the anodic oxide film are formed. Aluminum alloy vacuum vessel, a negative electrode terminal for applying a voltage to the negative electrode, an extraction electrode terminal for applying a voltage to the extraction electrode, and applying a voltage to both the negative electrode and the extraction electrode. An aluminum alloy vacuum device provided with a drive power supply, comprising: an ion electrode provided near an exhaust port for promoting the discharge of ions; and an ion electrode power supply for applying a voltage to the ion electrode. A vacuum apparatus made of an aluminum alloy, wherein a power source is a low-frequency voltage having a frequency of 5 Hz or less and has a function of generating a sine wave or a pulse wave. 2. The aluminum alloy vacuum apparatus according to claim 1, wherein the thickness of the barrier layer between the cathode and the cathode terminal is 10 nm or less. 3. An aluminum alloy vacuum apparatus according to claim 1, wherein said drive power supply has a function of generating a pulsed voltage within 50 ms and a voltage of 300 V or more. 4. A negative electrode which fills micropores of an anodic oxide film formed on the vacuum side surface of a vacuum vessel and emits electrons by electric field radiation, and an extraction electrode provided on the surface of the anodic oxide film. A vacuum vessel made of an aluminum alloy, a negative electrode terminal for applying a voltage to the negative electrode, an extraction electrode terminal for applying a voltage to the extraction electrode, and a voltage applied to both the negative electrode and the extraction electrode. An aluminum alloy vacuum device comprising a drive power source to be applied, and evacuating the inside of the aluminum alloy vacuum vessel, and applying a negative voltage between the negative electrode terminal and the extraction electrode terminal to increase the degree of vacuum. In the driving method, the voltage applied between the negative electrode terminal and the extraction electrode terminal is such that a pulsed voltage of 300 V or more within 50 ms is first applied at least once, and then The driving method of an aluminum alloy vacuum apparatus and applying a low voltage of normal. 5. An ion electrode for facilitating exhaustion of ions near an exhaust port, wherein a low frequency voltage of 5 Hz or less and a sine wave or a pulse wave are applied to the ion electrode. A method for driving a vacuum device made of an aluminum alloy according to claim 4.