JP2003218096A - Vacuum processing system for generating oxygen ion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen ion generator exhibiting useful handling performance in which a desired quantity of negative charge oxygen ions can be obtained through a simple structure. <P>SOLUTION: In the vacuum processing system 1 having an ion source chamber 2 comprising a porous ceramic substrate 29, a lamp 27, a reflector 28 and a gas introduction pipe 31, the porous ceramic substrate 29 is heated by means of the lamp 27 and the reflector 28 under an atmosphere of oxygen supplied from the gas introduction pipe 31 thus generating oxygen ions. The porous ceramic substrate 29 is disposed oppositely to a porous conductive plate 19 through an electric insulating material 6. Furthermore, the porous conductive plate 19 is brought to the ground potential and preferably applied with a voltage with the porous ceramic substrate 29 as a negative electrode. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum processing apparatus for generating oxygen ions.

[0002]

2. Description of the Related Art FIG. 1 is a schematic plan view of a conventional oxygen ion generator. Referring to FIG. 1, oxygen ion generator 1
Is composed of a metal ion source chamber 2, a charge conversion cell chamber 4 having a charge conversion cell 3, and an ion irradiation chamber 5. Further, the ion source chamber 2, the charge conversion cell chamber 4, and the ion irradiation chamber 5 are φ4 to 8 mm through an insulating cylinder 6 made of alumina or epoxy resin.
The opening 7 of the ion source chamber 2 formed of a circular hole of a certain degree is in communication with the ion source chamber side opening 8 and the irradiation chamber side opening 8 ′ of the charge conversion cell 3.

Inside the ion source chamber 2, a filament 1 that can be operated by an external filament power source 9 and is made of a refractory metal such as tungsten, tantalum, or rhenium is used.
0 is installed, and the ion source chamber 2 itself is electrically connected to the arc power source 11 and the extraction electrode power source 12 to set the container potential. In addition, the gas introduction port 13 of the ion source chamber 2 is connected to the oxygen cylinder 1 through the introduction valve 14.
5 is connected to a gas flow rate controller 16 and a pressure reducer 17 which communicate with each other. These gas introduction parts are made of metal in order to prevent ignition due to static electricity.

On the other hand, in the vicinity of the ion source chamber side opening 8 of the charge conversion cell 3 inside the charge conversion cell chamber 4, an extraction electrode 19 which is insulated from the cell 3 by an insulating sleeve 18 and is formed in a tapered shape is provided. ing. At this time, the minus side of the extraction electrode power source 12 is grounded, and the extraction electrode 19 is set to the ground potential. Further, a tip end hole 20b of a nozzle portion 20a of the vaporizer 20 is provided at a substantially central portion of the charge conversion cell 3 so as to project into the cell 3 from a lower portion. Coil heaters 21a and 21b are wound around the charge conversion cell 3 and vaporizer 20 from the outside for keeping heat.

In the irradiation chamber 5, the substrate stage 2
An irradiation object 23 made of an oxide to be held on the substrate 2 is provided so that the current flowing from the substrate stage 22 can be measured by an ammeter 24.

When the oxygen ion is generated by the conventional apparatus configured as described above, the entire apparatus 1 is previously vacuumed via a gas exhaust port 25 of the ion source chamber 2 and a gas exhaust port 26 of the irradiation chamber 5 (not shown). 1.3 × 1 by exhaust pump
The pressure is set to a low pressure of 0 ^-3 Pa or less, and then the filament power supply 9 is activated to start thermionic emission from the surface of the filament 10 in the incandescent state. In this state, a voltage of 40 to 130 V is applied by the arc power supply 11, and the gas flow rate controller 16 and the pressure reducer 17 are operated to change the flow rate from 2 to 2.
The introduction valve 14 is opened so that the pressure is about 1 atm with 10 sccm of oxygen gas, and oxygen gas is introduced into the ion source chamber 2. At this time, oxygen plasma is generated by the hot electrons from the incandescent filament 10 and the introduced oxygen gas. In this state, a voltage of 15 to 20 kV is applied by the extraction electrode power source 12 to generate the ion source chamber 2
Positively charged oxygen ions are emitted from the opening 7 of
The flight orbit at that time is maintained and the light is injected into the charge conversion cell 3 through the opening 8.

On the other hand, in the charge conversion cell 3, the vaporizer 20 arranged at the lower portion is filled with 3 to 5 g of metallic sodium, and the cell 3 and the vaporizer 20 are connected to each other.
The temperature is kept at about 0 to 400 ° C., and the vapor flow from the cell 3 to the irradiation chamber 5 is generated by the sodium vapor generated in the vaporizer 20.

At this time, as described above, the positively charged oxygen ions that have entered the charge conversion cell 3 collide with sodium atoms or sodium molecules in sodium vapor, and in the process electrons of the sodium atoms are stripped, which causes positive charges. The charged oxygen ions are converted into negatively charged ones (see FIG. 2).

The oxygen ions thus obtained are useful for an oxidation process for manufacturing a semiconductor and an oxidation process for a transparent conductive film for a display device, and are also used for sterilization utilizing the oxidizing power in the chemical field. be able to.

[0010]

By the way, in the above-mentioned conventional oxygen ion generator, positively charged oxygen ions are first generated and then converted to negatively charged oxygen ions to obtain desired oxygen ions. There is. Therefore, the apparatus becomes complicated corresponding to the multi-step process, and it becomes difficult to change the oxygen ion generation conditions.

For example, in order to increase the amount of ions, the immediate effect can be expected by widening the opening 7 of the ion source chamber 2, but at this time, the plasma ignition of the filament 10 in the ion source chamber 2 is performed. 1.3 × 10Pa
It is necessary to maintain a moderate pressure condition, and for this purpose, it is required to accurately introduce a large amount of oxygen gas into the ion source chamber 2. Further, in order to sufficiently emit positively charged oxygen ions generated in the ion source chamber 2 to reach the conversion cell 3, the opening 7 serving as an anode and the extraction electrode 1 are provided.
It is necessary to keep the potential difference between the electrodes 9 and 9 stable, but for this purpose, the pressure condition between the electrodes is preferably 1.3 × 10 ⁻³ Pa or less. Therefore, a powerful vacuum exhaust pump is required for the ion source chamber 2.

Such a problem in handling is caused by the irradiation chamber 5
Is similar to the above, for example, when the irradiation chamber side opening 8 ′ of the charge conversion cell 3 is widened to increase the amount of ions, oxygen ions are countered against the sodium vapor that increases and flows out accordingly. In order to ensure that the mean free path of oxygen ions can be secured, it is necessary to set the inside of the conversion cell 3 to 1.3 × 10 ⁻³ Pa or less in order to ensure that the average free path of oxygen ions is secured. Therefore, as in the case of the ion source chamber 2, the irradiation chamber 5 also has a powerful vacuum exhaust pump.

Furthermore, if the applied voltage (about 20 kV in the apparatus of FIG. 1) to the extraction electrode 19 for generating oxygen ions is reduced for the purpose of, for example, power saving, the positively charged oxygen ions in the ion source chamber 2 are generated. Since the production amount is reduced, the charge conversion efficiency is reduced when negatively charged oxygen ions are produced by using this as a conversion species.

In addition to this, the conversion loss in the process in which oxygen ions are converted from positive charges to negative charges in the conversion cell 3 cannot be ignored.

In view of the above problems, the present invention can obtain a desired amount of negatively charged oxygen ions with a simple structure, and
For example, it is an object of the present invention to provide an oxygen ion generator that is useful in handling because it is possible to easily change the conditions such as the irradiation area of the ion beam for increasing the amount of ions and the applied voltage to the extraction electrode. .

[0016]

In order to solve the above-mentioned problems, the present invention has a porous ceramic substrate, a heating means and an oxygen introducing means, and heats them in an oxygen atmosphere when the oxygen introducing means is operated. Oxygen ions are generated by a vacuum processing apparatus configured to heat the porous ceramic substrate by the means.

With such an apparatus, oxygen species can be desorbed from the porous ceramic substrate as negatively charged oxygen ions, and the amount of negatively charged oxygen ions thus generated can be reduced. Handling is improved in that the conditions can be easily changed, such as the amount can be increased or decreased by adjusting the heating means.

In this case, when the above-mentioned vacuum processing apparatus for oxygen ion generation is constructed such that the porous conductive plate is opposed to the porous ceramic substrate through the electrically insulating material, negatively charged oxygen generated from the porous ceramic substrate is generated. Since the irradiation direction of the ions is focused toward the porous conductive plate, the ion beam due to this becomes high density after passing through the conductive plate. Therefore, it becomes easy to secure a desired amount of oxygen ions.

Further, in this case, when the porous conductive plate is grounded and a voltage is applied with the porous ceramic substrate as a negative electrode, the generated oxygen ions can be surely charged to a negative charge.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 is a schematic plan view of a vacuum processing apparatus for oxygen ion generation according to the present invention. Portions having the same functions as those in FIG. 1 are designated by the same reference numerals. Referring to FIG. 3, an ion source chamber 2 and a substrate stage 22 holding an irradiation target 23 are arranged in an irradiation chamber 5 provided with an exhaust port 26, and the substrate stage 22 has an ammeter outside the apparatus. 24 is connected.

In the ion source chamber 2, there are arranged a lamp 27 operated by the filament power source 9, a reflecting plate 28 for reflecting the heat generated by the lamp 27, and a disk-shaped porous ceramic substrate 29 of about 5 cm. The porous ceramic substrate 29 is fixed by a holder 30 provided on the wall surface of the ion source chamber 2. Further, on the substrate stage 22 side of the porous ceramics substrate 29, extraction electrodes 19 made of a porous metal plate are attached at a distance of about 3 mm from the substrate 29 via an electric insulating material 6. At this time, as a metal forming the extraction electrode 19, an antioxidizing material such as molybdenum is used. Further, a gas introduction pipe 31 is inserted and provided in the space surrounded by the reflection plate 28.

The irradiation chamber 5 and the ion source chamber 2 are made of metal in order to ensure conductivity, but they are electrically insulated by the insulator 32, and the extraction electrode 19 at the ground potential, the irradiation chamber 5, and The potential difference from the ground cover 33 is kept.

In order to generate oxygen ions using the apparatus of FIG. 3, the inside of the irradiation chamber 5 is kept at 1.3 × 10 ⁻³ Pa or less by a vacuum exhaust pump (not shown) connected to the exhaust port 26 in advance. In this state, the lamp 2 is powered by the filament power supply 9.
Turn on 7. At this time, the light emitted from the lamp 27 is reflected by the reflection plate 28 and the porous chamber ceramic substrate 29 is heated. The substrate temperature at that time is preferably adjusted to a range of 600 to 900 ° C. by adjusting the filament power supply 9.

Then, the introduction valve 14 is opened so that the flow rate of the oxygen gas is 0.01 via the gas introduction pipe 31.
The space surrounded by the reflection plate 28 is maintained at about 1.3 × 10 ⁻³ Pa while introducing the gas at a flow rate of about 0.1 sccm.

In this manner, the extraction electrode power source 12 applies a voltage of -300 V to the ion source chamber 2. At this time, the porous ceramics substrate 29 becomes a negative electrode, and as a result, oxygen species in the space surrounded by the reflection plate 28 are negatively charged and pass through the porous ceramics substrate 29, so that the inside of the irradiation chamber 5 is charged. And hits the irradiated body 23 to generate an electric current.

The current measured by the ammeter 24 of the apparatus of FIG.
The value is about 2mA (about 100μA / cm ²), The current of Figure 1
Much better than the current value of 2 to 15 μA obtained by the total of 24 measurements
Good results are obtained.

[0027]

As is apparent from the above description, in the vacuum processing apparatus for oxygen ion generation according to the present invention, the oxygen species as the origin of oxygen ions are directly converted into negative charges without undergoing charge conversion from positive to negative. It is charged and oxygen ions are generated. Since the oxygen ion generation process is simplified in this way, charge conversion loss during oxygen ion generation can be suppressed and the amount of ions can be secured efficiently, and the device structure is also simplified, making it easy to handle. Improves the usefulness of. Therefore, it can be expected that the conditions for generating oxygen ions can be easily changed.

[Brief description of drawings]

FIG. 1 Conventional oxygen ion generator

2 (a) to (c) The generation process of negatively charged oxygen ions in the oxygen ion generator shown in FIG.

FIG. 3 is a vacuum processing apparatus for generating oxygen ions of the present invention

[Explanation of symbols]

1 Vacuum processing equipment for oxygen ion generation 6 electrical insulation 12 Power supply for extraction electrode 19 Perforated conductive plate 27 lamps (heating means) 28 Reflector (heating means) 29 Porous ceramic substrate 31 Gas introduction pipe

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shen Guohua             2500 Hagien, Chigasaki-shi, Kanagawa Al             In the back (72) Inventor Koichi Yamaguchi             2500 Hagien, Chigasaki-shi, Kanagawa Al             In the back F-term (reference) 5F045 AA20 AC11 AE11 CA15 DP05                       EK11

Claims (3)

[Claims] 1. A porous ceramic substrate, a heating means, and an oxygen introducing means, wherein the porous ceramic substrate is heated by the heating means under an oxygen atmosphere formed by operating the oxygen introducing means to generate oxygen ions. A vacuum processing apparatus for generating oxygen ions, which is characterized by generating oxygen ions. 2. The vacuum processing apparatus for oxygen ion generation according to claim 1, wherein a porous conductive plate is opposed to the porous ceramic substrate with an electrically insulating material interposed therebetween. 3. The oxygen ion generating vacuum processing apparatus according to claim 2, wherein the porous conductive plate is grounded and a voltage is applied with the porous ceramic substrate as a negative electrode.