JP2951477B2 - Method of changing the potential of an object, and method of neutralizing a predetermined charged object - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for changing the potential of an object and a method for removing electricity from a predetermined charged object. In particular, the present invention relates to a method for changing the potential of an object or ionizing a charged object by ionizing the atmosphere in a gas atmosphere at atmospheric pressure or the like.

[0002]

2. Description of the Related Art Various types of conventional ion generators are used depending on the purpose. Ultraviolet rays and X-ray microwaves are used as energy sources for generating ions. Used. Conventionally, for this kind of purpose, for example, ultraviolet light has been used, but the ion voltage of gas molecules in the atmosphere is often in the range of 8 to 15 electron volts, and ultraviolet light can achieve a sufficient purpose. The effect was not significant.

Attempts have been made to utilize X-rays by SOR (synchrotron radiation) for the same purpose. However, SOR is a huge device that is not industrially established, and cannot be compared with the present invention even if the wavelength range is similar. On the other hand, in another example of the conventional ion source,
Although microwave discharge and the like were used, large equipment was required, and there was a problem in terms of energy uniformity and the like. An object of the present invention is to solve such a problem.

[0004]

According to the present invention, there is provided an ion generating apparatus applied to a method for changing the potential of an object and a method for neutralizing a predetermined charged object according to the present invention, wherein the main wavelength of X-rays is in the range of 2 to 20 angstroms. Beryllium (B
e) An X-ray tube having a window is provided, and an element to be ionized is contained in a region irradiated with X-rays from the Be window.

According to a first aspect of the present invention, there is provided a method for changing a potential of an object, wherein a target to which a predetermined target voltage and a target current are applied is provided at a position where the atmosphere in which the predetermined object is arranged is irradiated with X-rays. In addition, an X-ray tube having a beryllium window is arranged, and the elements or substances contained in the atmosphere of the region irradiated with X-rays whose main wavelength is in the range of 2 Å to 20 Å from the beryllium window are ionized, A method for changing the potential of an object, wherein the potential of the predetermined object in the atmosphere containing ions is brought close to the potential of the atmosphere.

According to a second aspect of the present invention, a target to which a predetermined target voltage and a predetermined target current are applied is provided at a position where X-rays are applied to an atmosphere in which a predetermined charged object to be neutralized is arranged. And an X-ray tube having a beryllium window, and ionizing elements or substances contained in an atmosphere in a region irradiated with X-rays having a main wavelength in a range of 2 Å to 20 Å from the beryllium window. A method for removing static electricity from a predetermined charged object in an atmosphere including the following.

[0007]

[Function] Soft X is used as an energy source for ion generation.
The use of lines per se has been attempted in the past. However, it has not been clear to what extent the wavelength of the soft X-ray is effective. Recently, the technology of an X-ray tube having a Be (beryllium) window has been established. Considering the use of this technology, when the wavelength of soft X-rays is long, the absorption loss due to Be is N ₂ , O _2, etc. X-rays having a wavelength of about 20 angstroms or more were found to be disadvantageous because the loss ratio sharply increased.

On the other hand, it has been found that when the wavelength of soft X-rays is reduced to 2 angstrom or less, absorption by a target substance including an atmosphere is reduced, and the soft X-ray is not suitable for target ionization. Thus, a suitable wavelength for use as an ionization energy source is effectively in the range of 2 to 20 angstroms.

At a wavelength in this range, absorption loss at the Be window is relatively small, and ions are generated and disappear during traveling over a relatively short distance (for example, 10 cm) in an atmosphere at about atmospheric pressure. If you leave, there is no effect on the human body and it is safe. That is, the limited area referred to in claim 2 usually indicates about 10 to 20 cm or less, and a long distance range such as 1 m or more is not considered from the viewpoint of industrial use described later.

The X-ray tube used in the method of changing the potential of the object and the method of removing the electric charge of a predetermined charged object may be, for example, a target voltage of about 5 kV and a target current of about 20 μA. It has the advantage of being easy and not generating noise.

[0011]

Hereinafter, the present invention will be described more specifically. The ion generator applied to the method for changing the potential of an object of the present invention and the method for neutralizing a predetermined charged object includes an X-ray tube having a Be window, and the X-ray tube emitted from the Be window.
The structure is such that the line is irradiated to all ionized elements. Here, the wavelength of the X-ray is 2 to 15 angstroms,
Thereby, it is possible to provide a method of changing the potential of a good object and a method of removing a predetermined charged object.

For example, in a health apparatus for generating ions in the atmosphere, emitting ions having a wavelength of about soft X-rays to generate ions requires a conventional discharge device such as an ionizer to generate noise or high pressure. Compared to the disadvantages such as the exposure of the terminals, the operation was simple and clean, and the efficiency was high.

As a specific application of the method of changing the potential of the object and the method of removing the electric charge of a predetermined charged object, for example, in an electrostatic copying machine, a specific limited object is charged in order to charge a nearby object. It can be used effectively to generate ions in space. That is, by irradiating the limited space with X-rays from the Be window, the material or atmosphere in the space can be ionized. As described above, ions can be generated to charge or eliminate a predetermined object in a predetermined space (that is, to bring the potential of the predetermined object closer to the potential of an ionized atmosphere).

Further, when the discharge of the gas-filled discharge tube is started, the discharge start can be facilitated by providing an ion generator near the discharge tube. Further, incorporating this is advantageous in that ionization is limited to a limited range, and is advantageous in that it does not pass through an extra window and also in terms of safety. In this case, the ion generation space may not always be at atmospheric pressure, but even when the gas pressure is lower than atmospheric pressure, the same effect can be expected effectively because this wavelength has a high ionization efficiency.

Further, various chemical reactions can be accelerated and controlled by an ionizer. For example, in a CVD method in which an epitaxial film or an oxide film is formed and grown on a silicon substrate by a chemical reaction, or in a dry etching method in which a reaction is easily performed and removed, an upper ion generator is provided nearby to perform the reaction. The reaction can be accelerated by ionizing the gas.

The pressure of the above-mentioned chemical reaction gas may be atmospheric pressure or decompressed. However, this distinction is not essential, and the present invention is not limited to about atmospheric pressure. Depending on the purpose of use, this includes cases under reduced pressure.

In addition to the above-described gas phase chemical reaction, the present invention can be applied to a thin film surface reaction. One example is plastic surface modification. For example, the surface of a polyvinylidene (PVF) film is irradiated with soft X-rays by an upper X-ray ionizer to supply ions from the atmosphere to the surface layer, thereby oxidizing unstable unsaturated bonds on the surface and thereby forming a stable film. Can be turned into layers. This process is convenient and advantageous because it can be performed at atmospheric pressure. Alternatively, the aluminum casting surface
By the above treatment, a stable protective film layer can be obtained. This is an extremely simple method as compared with a conventional method in which a protective film is formed by an electrolytic plating method.

In semiconductor processing, ions are used in impurity implantation by an ion beam, sputtering, and the like. These ions are effective as a source of these ions. That is, in the processing apparatus, the ionization apparatus of the present invention is installed at a portion to be an ion source, and the raw material gas is soft X
Irradiate with lines. Then, the generated ions are accelerated by a suitable voltage through a slit or the like, and are introduced into a vacuum chamber to obtain an ion beam. According to the present invention, ions can be generated in a small and effective manner as compared with the conventional example using microwave discharge. In addition, ions can be generated within a required limited range depending on the absorption length of soft X-rays, the irradiation direction, and the like.

Further, even when a photochemical reaction as exemplified in a so-called photoresist used in semiconductor processing is caused in a thin film solid phase, the soft X-rays of the wavelength according to the present invention generate ions in the thin film solid phase. Therefore, instead of causing photoetching by light irradiation, the same effect can be obtained by irradiation with soft X-rays. Of course, in this case, the atmosphere needs to be a vacuum. This method offers a promising solution to the current situation in which the wavelength used is shortened due to decomposition in recent light exposure methods, and there is no suitable intense ultraviolet light source, which causes difficulty.

The above exposure is similar to the so-called X-ray exposure method, but differs in its means and apparatus. That is, in the present invention, the wavelength is selected by the absorption difference from the Be plate.
An e-plate is provided, and irradiation is performed through this.

This Be plate has a role similar to that of a photomask conventionally used in X-ray exposure, but has not been used. As a conventional mask (support film), a BN film, a SiN film, a polyimide, or the like is used. However, a thin film having a smaller X-ray absorption than that of the mask and capable of being used as a mask can be obtained. The chemical reaction method using X-ray induced ions of the present invention in combination with the above is effective. of course,
A mask material pattern can be placed on the Be thin film and applied to photolithography.

The Be film is also useful as a partition between the irradiation system and the reaction system, or as a partition window. The use of Be in a soft X-ray apparatus is one of the features of the ionization apparatus according to the present invention. It is.

Next, the criteria for selecting the soft X-ray wavelength will be described. For example, in the case of ionizing the atmosphere, it is necessary to increase the absorption in the atmospheric gas (for example, nitrogen N) as compared with the absorption loss in the Be plate. From this point, the upper limit of the wavelength is determined. The upper limit is the wavelength end, which is about 30 angstroms. But N and Be
Is minimum around 3.5 angstrom and gradually decreases toward shorter wavelengths. As the wavelength decreases, the absorption coefficient for N also decreases, so that the ionization efficiency also decreases. As we progress to longer wavelengths,
Efficiency is reduced by absorption in Be.

Considering the absorption length for ionizing the gas, a too small absorption length cannot be applied, so that the ionization absorption rate is 20 for a practical length (for example, 10 cm).
%, The lower limit is a wavelength of about 2.5 angstroms. Therefore, the range of 30 to 2.5 angstroms is appropriate, but the upper limit is set to 12 angstroms from the viewpoint of materials that can be selected as the X-ray tube target material. That is, the materials that can be selected in this range are Na (sodium), Mg (magnesium), Al
(Aluminum), Si (silicon), K (potassium), Ca (calcium), Ti (titanium), V (vanadium) and the like.

An example of the case of a CVD epitaxial reaction by X-rays will be described.
Since it is a gas such as H4, comparison of absorption between Be and Si becomes a problem. That is, since the characteristic end of Si is at 7.1 Å, this is the upper limit. The lower limit is determined by the Si absorption length, and is similarly 2.5 Å. During this time, the minimum value is around 2.5 Å. The most preferred wavelength has an upper limit of 7 angstroms and a lower limit of 2.5 angstroms.
Therefore, the range is expressed as about 7 to 2 angstroms.

As an example of the solid-phase reaction by X-ray, an example of X-ray exposure photolithography will be described. If the reactant in this case is a photoresist mainly composed of Si, the same as described above. If it is a photoresist mainly composed of organic polymer, C (carbon)
And Be, from which it can be seen that the upper limit and lower limit of the wavelength may be 15 to 2.5 angstroms as described above. The same value may be used for CVD of Al.

When considered as an ion beam source, M
Any ion source such as g, Al, Si, P (phosphorus), and Ar (argon) may be the same as Si. The same applies to Si in the case of metal organic CVD or the like. Ga (gallium)
For those with relatively large atomic weights, such as those with a lower wavelength limit of about 2 Å, the efficiency still does not decrease so much, but the efficiency is still higher for longer wavelengths.
The scope of the present invention is the same as that of Si or the like.

[0028]

According to the present invention, the potential of a predetermined object is brought close to the atmosphere by ionizing extremely efficiently by a simple method using an X-ray tube having a Be window. For example, there is an effect that a charged object can be neutralized. Therefore, it can be extremely widely used in various industrial fields.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01J 37/08 H01J 37/08 H01L 21/302 H05F 3/06 H05F 3/06 H01L 21/302 Z (58) Fields surveyed (58) Int.Cl. ⁶ , DB name) G21H 5/00 C08J 3/28 G03G 15/02 G21K 5/02 H01J 27/16 H01J 37/08 H05F 3/06 JICST file (JOIS)

Claims (2)

(57) [Claims] 1. An atmosphere in which a predetermined object is arranged is X
An X-ray tube having a built-in target to which a predetermined target voltage and target current is applied and having a beryllium window is arranged at a position where the beam is irradiated, and a main wavelength from the beryllium window is in a range of 2 Å to 20 Å. An object characterized in that the potential of the predetermined object in the atmosphere containing the ions is made closer to the potential of the atmosphere by ionizing elements or substances contained in the atmosphere in the region irradiated with the X-rays. To change the potential of 2. An X-ray tube having a built-in target to which a predetermined target voltage and a target current is applied and having a beryllium window is provided at a position where X-rays are irradiated to an atmosphere in which a predetermined charged object to be neutralized is arranged. By arranging, ionizing elements or substances contained in the atmosphere in a region irradiated with the X-rays whose main wavelength is in a range of 2 Å to 20 Å from the beryllium window, And discharging the predetermined charged object.