JP2001185089A - Excimer irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excimer irradiation device which is capable of improving an irradiation efficiency of excimer light. SOLUTION: This excimer irradiation device 1 has two or more excimer lamps 2 being disposed in exposed state. The excimer lamp 2 includes an excimer discharge tube 4, an outer electrode 5 disposed at outside of the excimer discharge tube 4, an outer tube 6 disposed at further outside of the outer electrode 5, an inner tube 7 disposed at inside of the excimer discharge tube 4, an inner electrode 8 disposed within the inner tube 7, and discharging gas 9 filled into a sealed space between the excimer discharge tube 4 and the inner tube 7. Nitrogen gas 3 can flow in and out a space of the inner tube 7 and a space between outer tube 6 and the excimer discharge tube 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excimer irradiator, and more particularly to an excimer irradiator in which an excimer light irradiation efficiency is further improved by using an excimer lamp which can be used in an exposed state.

[0002]

2. Description of the Related Art An excimer irradiation apparatus is an apparatus for irradiating a single wavelength ultraviolet light (hereinafter referred to as "excimer light") from an excimer lamp by a dielectric barrier discharge called a silent discharge. In a dielectric barrier discharge, when a high voltage is applied to an excimer lamp filled with a discharge gas that forms excimer molecules, excimer molecules are formed in the excimer lamp and the excimer molecules transition to a ground state. This is a discharge type that emits a single wavelength excimer light. An excimer irradiation apparatus using such a dielectric barrier discharge generates excimer light of 172 nm, 193 nm, 207 nm, 222 nm, or 248 nm according to the type of discharge gas in the excimer lamp.

[0003] Excimer light can react with air or water to generate excited oxygen atoms or OH radicals that effectively decompose organic compounds, and is therefore used for decomposing contaminants composed of organic compounds. I have. Excimer light has a high photon energy, and is therefore used for a surface modification treatment or the like in which an excimer light is directly reacted with an irradiation target. For example, in the field of the semiconductor industry, it is applied to dry cleaning for decomposing organic compounds contaminating silicon wafers and glass substrates, or to surface activation treatment and soft ashing of semiconductor materials. In addition, it has been applied in various fields such as surface emission treatment or surface modification treatment of resins and metal materials in the fields of fluorescence emission of plasma display panels, LCD processes, and materials. Furthermore, excimer light is used in the field of environmental technology for ozone generation, water and air pollution purification, and ultrapure water production processes.

In recent years, in such excimer irradiation apparatuses, various devices for efficiently irradiating the generated excimer light have been studied. For example, (a) improving the irradiation efficiency of excimer light by introducing a nitrogen gas into a container to which the excimer lamp is mounted so that excimer light generated from the excimer lamp is not absorbed.
(B) The glass window of the container to which the excimer lamp is attached,
By changing the material of the discharge vessel of the excimer lamp to quartz glass with excellent transmittance, the transmittance of excimer light is increased to improve the irradiation efficiency. (C) A reflector is provided on the back side of the excimer lamp. The efficiency of excimer light irradiation is improved by devising the shape of the reflector.

[0005]

However, when a nitrogen gas is flowed into a container in which an excimer lamp is mounted, a glass window that transmits the excimer light needs to have a sufficient strength. Then, there is a problem that the transmittance of the excimer light decreases. In this case, quartz glass having better transparency can be used, but there is a problem that thick quartz glass must be used because it does not solve the problem of insufficient strength, and it is expensive and not economical.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem, and has as its object to provide an excimer irradiating apparatus in which an excimer light irradiation efficiency is further improved by using an excimer lamp which can be used in an exposed state. And

[0007]

The invention according to claim 1 is an excimer irradiation apparatus having two or more excimer lamps arranged in an exposed state, wherein the excimer lamp is:
An excimer discharge tube, an external electrode disposed outside the excimer discharge tube, an external tube disposed further outside the outer electrode, an internal tube disposed inside the excimer discharge tube, and the internal tube Having an internal electrode disposed therein, and a discharge gas filled in a sealed space between the excimer discharge tube and the internal tube. It is characterized in that nitrogen gas flows into and out of the space between the discharge tube.

According to the present invention, since the excimer lamp is disposed in the container in an exposed state, the excimer lamp can be brought closer to the irradiation object to improve the irradiation efficiency, and the excimer lamp can be mounted as in the prior art. There is no need to flow nitrogen into the container, and no glass window is required. This eliminates the need for thick quartz glass, and has the advantage of being economical. Further, in the present invention, for the purpose of protecting the external electrodes and preventing the absorption of excimer light, nitrogen gas flows into and out of the space in the inner tube of the excimer lamp and in the space between the outer tube and the excimer discharge tube. However, since the outer tube used is a cylindrical tube having excellent strength, it can sufficiently withstand the nitrogen gas pressure, and the thickness of the outer tube can be reduced. As a result, the transmittance of excimer light is not reduced, which is economically preferable. Therefore, according to the excimer irradiation apparatus of the present invention,
Irradiation can be performed with high irradiation efficiency.

According to a second aspect of the present invention, in the excimer irradiating apparatus according to the first aspect, the excimer lamp includes five excimer lamps.
It is characterized by being arranged side by side with a gap of 0 mm or less.

According to the present invention, by setting the interval between the excimer lamps that can be closer to the object to be irradiated within the above-mentioned predetermined range, the illuminance distribution on the object to be irradiated can be further improved with high irradiation efficiency. It can be uniform.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an excimer irradiation apparatus according to the present invention will be described with reference to the drawings.

The present invention has the problem that a thick glass window having sufficient strength to withstand the pressure of nitrogen gas flowing in a container reduces the transmittance of excimer light, and is expensive when quartz glass is used. The problem that it is not economical has been solved by using an excimer lamp that can be used in an exposed state and by further flowing nitrogen gas into an external tube.

FIG. 1 is a front end view showing an example of the excimer irradiation apparatus 1 of the present invention, FIG. 2 is a side view of the excimer irradiation apparatus 1 of FIG. 1, and FIG. FIG. 4 is a cross-sectional view of the excimer lamp 2 of FIG. 3 in a horizontal direction.

The excimer irradiation apparatus 1 of the present invention has two or more excimer lamps 2 arranged in an exposed state, for example, four excimer lamps in FIG. 1, and the excimer lamps 2 are arranged at regular intervals so as to directly face the object to be irradiated. Are arranged side by side. The number of the excimer lamps 2 is not particularly limited, and a large-area excimer irradiator can be provided by arranging a large number of excimer lamps 2. A power supply unit, a nitrogen gas flow control valve, and the like can be appropriately provided in a portion other than the excimer lamp 2 of the excimer irradiation device 1. Further, a reflector 10 for reflecting the excimer light emitted from the excimer lamp 2 can be provided on the opposite side of the irradiation object.

In the present invention, by providing the excimer lamps 2 arranged side by side in an exposed state, the excimer lamps 2 can be brought closer to the object to be irradiated, and as a result, the irradiation efficiency of the excimer lamps 2 can be further improved. Can be. Note that the excimer irradiation device 1 of the present invention
There is no conventional glass window, for example, a quartz glass window, which is economically advantageous.

Next, the structure and details of the excimer lamp 2 will be described.

The excimer lamp 2 includes an excimer discharge tube 4
And an external electrode 5 arranged outside the excimer discharge tube 4
An outer tube 6 disposed further outside the outer electrode 5,
An inner tube 7 arranged inside the excimer discharge tube 4, an internal electrode 8 arranged inside the inner tube 7, and an excimer discharge tube 4
Discharge gas 9 filled in a sealed space between
(See Japanese Patent Application Laid-Open No. 11-319816). Then, the vicinity of both ends in the longitudinal direction of the excimer lamp is fixedly mounted on the case 21.

Further, in the present invention, the nitrogen gas 3 flows into and out of the space inside the inner tube 7 and into the space between the outer tube 6 and the excimer discharge tube 4. It is preferable that the nitrogen gas flows in and out of such a space while maintaining a pressurized state. The inflow and outflow of the nitrogen gas 3 is for the purpose of preventing oxidation of the external electrode 5 and the internal electrode 8 and preventing absorption of excimer light. And the thickness of the outer tube 6 can be reduced. As a result, unlike the conventional case where a thick quartz glass window is used, the transmittance of excimer light is not reduced, which is economically preferable. Therefore, the excimer lamp 2 can be brought closer to the irradiated object, and higher irradiation efficiency can be realized. There is also an advantage that the excimer lamp 2 can be cooled from the inside and the outside. Note that an inert gas other than nitrogen gas, for example, an inert gas such as argon gas may be used, but nitrogen gas is preferable from the viewpoint of economy.

The excimer discharge tube 4 is a tubular container in which a predetermined type of discharge gas 9 is filled in a sealed space between the excimer discharge tube 4 and an inner tube 7 disposed inside the discharge tube. It is made of a dielectric material that is easy to use. Usually, a quartz tube or a synthetic quartz tube having excellent light transmittance is used. A quartz tube or a synthetic quartz tube having a thickness of about 1.0 to 2.0 mm is used. Note that the length and diameter of the excimer discharge tube 4 are appropriately set according to the area of the irradiation surface designed according to the size of the irradiation target and the irradiation time. Usually 30 diameter
A quartz tube having a length of about 250 mm and a length of about 250 mm is used.
The excimer discharge tube 4 preferably has a closed end, but if both ends are open, it is necessary to seal the end.

The external electrode 5 is disposed over the entire outer peripheral surface of the excimer discharge tube 4 and is made of stainless steel, aluminum, an aluminum alloy, copper, copper oxide, or an alloy thereof, yttrium oxide, yttrium aluminum oxide, or the like. Those exhibiting good metal conductivity and having a high discharge rate are preferably selected. The shape of the external electrode 5 is not particularly limited, such as a plate shape or a mesh shape.
It is preferable to use a punching metal with a thickness of about 0.5 mm in which a large number of through holes such as hexagons are formed so as not to disturb the optical path of the excimer light irradiated from the substrate.

The external tube 6 is disposed further outside the external electrode 5, and a quartz tube or a synthetic quartz tube is used. The outer tube 6 forms a space between the outer tube 6 and the excimer discharge tube 4, and is provided so that nitrogen gas 3 for preventing oxidation of the external electrode 5 and preventing absorption of excimer light can flow into and out of the space. Have been. Since the outer tube 6 has a cylindrical shape having excellent strength, it can sufficiently withstand the nitrogen gas pressure flowing into and out of the outer tube. Therefore, the thickness of the outer pipe 6 is set to 1.0 to 2.
The thickness can be reduced to about 0 mm. In the present invention, since the outer tube 6 can be made thinner in this manner,
Excimer light emitted from the excimer discharge tube 4
Can be reduced as much as possible when passing through. The outer tube 6 may be open at both ends or closed at the tip, and is not particularly limited. However, in the case of an open tube, it is necessary to seal the tip.

The excimer lamp 2 used in the present invention comprises:
Since such an external tube 6 is provided, it can be used even in an exposed state, and can irradiate an object with sufficient irradiation efficiency.

The inner tube 7 is provided substantially at the center of the excimer discharge tube 4, and usually a quartz tube or a synthetic quartz tube is used. The internal tube 7 has an internal electrode 8 provided inside thereof, and an inlet 11 and an outlet for the nitrogen gas 3 provided at one end thereof. As the inner tube 7, a tube whose end is normally closed is used (see FIG. 3).

The internal electrode 8 is provided inside the internal tube 7 and can be made of the same kind of material as that used for the above-mentioned external electrode 5. The internal electrode 8 exhibits good metal conductivity and has a high discharge rate. Is preferably selected. The shape of the internal electrode 8 is preferably a shape in which the nitrogen gas 3 entered from the inflow port 11 easily passes through the inside of the internal tube 7, for example, a mesh electrode. Since the mesh electrode has a space between the meshes, the nitrogen gas 3 easily passes therethrough.

The discharge gas 9 is sealed in the excimer discharge tube 4, and a high-frequency voltage is applied between the internal electrode 8 and the external electrode 5 provided inside and outside the excimer discharge tube 4 to discharge the discharge gas 9. Excimer light having a wavelength corresponding to the type of the gas 9 can be generated. The relationship between the type of the discharge gas 9 and the wavelength of the excimer light is, for example, krypton (Kr).
146 nm for gas and 172 nm for xenon (Xe) gas
nm, 191 nm for KrI gas, and 19 nm for ArF gas.
Excimer light of 3 nm, 222 nm of KrCl gas, and 248 nm of KrF gas are generated at a single wavelength. Therefore, by selecting the discharge gas 9,
Excimer light according to the purpose of use can be generated. The pressure of the discharge gas 9 in the excimer discharge tube 4 is appropriately set according to the type of gas and the desired illuminance of excimer light, but is usually about 10 to 60 kPa.

Next, the inflow / outflow path of the nitrogen gas 3 will be described.

In the present invention, the nitrogen gas 3 flows into and out of the space inside the inner tube 7 and into the space between the outer tube 6 and the excimer discharge tube 4. Therefore, as shown in FIG. 3, it is preferable to provide an inlet and an outlet for facilitating the flow of the nitrogen gas 3 into and out of each space.

Although the inflow / outflow path of the nitrogen gas 3 can be provided for each of the inner pipe 7 and the outer pipe 6, as shown in FIG. The nitrogen gas 3 in the inner pipe 7 is provided between the outer pipe 6 and the outer pipe 6.
It is preferable to provide an inflow / outflow path for flowing into the inner space, and to provide an outflow port 12 in the outer pipe 6. In addition, the nitrogen gas 3 may be made to flow into the outer pipe 6 first and then flow into the inner pipe 7. Furthermore, an inner pipe 7 or an outer pipe 6 having both open ends may be used so that the nitrogen gas 3 to be flowed easily flows in the space in the inner pipe 7 and the space in the outer pipe 6. When the inner pipe 7 or the outer pipe 6 having one open end is used, it is preferable to insert the small-diameter pipe 13 and guide the nitrogen gas 3 to the inner pipe 7 or the outer pipe 6.

Next, a detailed configuration of the excimer irradiation device 1 will be described.

In the excimer irradiation apparatus 1 of the present invention, the excimer lamps 2 which can be used in an exposed state are arranged, and the arrangement intervals are preferably 50 mm or less, preferably 20 mm or less. . The excimer lamps may be adhered to each other. By arranging the excimer lamps 2 in such a gap d, the illuminance distribution on the irradiation target can be made uniform. When the arrangement interval of the excimer lamps 2 exceeds 50 mm, the illuminance distribution of the irradiation target is disturbed. Such uniform illumination distribution
The difference is noticeable as a difference in the processing time for the irradiation target. For example, the decomposition rate of organic impurities attached to the irradiation target can be improved, and the processing time can be shortened.

In the excimer irradiation device 1, a reflector 10 can be provided on the back side of the excimer lamp 2. Reflector 1
Numeral 0 plays a role of reflecting the excimer light emitted toward the opposite side of the irradiation target, that is, the back side of the excimer lamp 2, toward the irradiation target. Usually, a mirror-finished stainless steel or a coated aluminum material is used, but the material is not particularly limited as long as it reflects excimer light preferably. The excimer irradiation apparatus 1 of the present invention is excellent in irradiation efficiency on an object to be irradiated and excellent in illuminance distribution. Therefore, a flat reflector 10 as shown in FIG. 1 is sufficient. The shape is not limited.

Further, the excimer irradiation apparatus 1 can be provided with a power supply unit, a nitrogen gas flow rate control valve, and the like.

The power supply is provided for applying a high-frequency voltage between the external electrode 5 and the internal electrode 8 constituting the excimer lamp 2. The high-frequency voltage has a frequency condition in which the resonance point matches the capacitance of the excimer lamp 2 within a frequency range of 1 to 20 MHz, and is output from the power supply unit.
Under such a frequency condition, a silent discharge can be caused in the excimer lamp 2 even with an applied voltage as low as 1 to 3 kV, for example.

Since the excimer irradiation apparatus 1 of the present invention includes two or more excimer lamps 2, a high-frequency voltage is applied to each of the excimer lamps 2. As an example, 13.
When a high frequency voltage of 56 MHz and 2 kV is applied, excimer light can be emitted from the outer peripheral surface of the excimer lamp 2 at an illuminance of 10 mW / cm ² , and excimer light can be generated with high luminous efficiency.

[0035]

As described above, according to the excimer irradiation apparatus of the first aspect, the irradiation efficiency can be improved by bringing the excimer lamp 2 closer to the object to be irradiated.
There is an advantage that it is more economical than the conventional one. Further, since the thickness of the external tube used can be reduced, the transmittance of excimer light is not reduced, which is economically preferable. With such an excimer irradiation apparatus of the present invention, high irradiation efficiency can be realized.

According to the excimer irradiation apparatus of the second aspect, the illuminance distribution on the object to be irradiated can be made more uniform under high irradiation efficiency.

[Brief description of the drawings]

FIG. 1 is a front end view showing an example of an excimer irradiation apparatus according to the present invention.

FIG. 2 is a side view of the excimer irradiation apparatus of FIG.

FIG. 3 is a longitudinal sectional view showing an example of an excimer lamp.

FIG. 4 is a cross-sectional view of the excimer lamp of FIG. 3 in a lateral direction.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 excimer irradiation device 2 excimer lamp 3 nitrogen gas 4 excimer discharge tube 5 external electrode 6 external tube 7 internal tube 8 internal electrode 9 discharge gas 10 reflector 11 inflow port 12 outflow port 13 small diameter pipe 21 case d gap

Claims (2)

[Claims] 1. An excimer irradiator having two or more excimer lamps arranged in an exposed state, wherein the excimer lamp comprises: an excimer discharge tube; an external electrode disposed outside the excimer discharge tube; An outer tube arranged further outside the electrode, an inner tube arranged inside the excimer discharge tube, an inner electrode arranged inside the inner tube, and a space between the excimer discharge tube and the inner tube. And a discharge gas filled in the sealed space, and nitrogen gas flows into and out of the space in the inner tube and the space between the outer tube and the excimer discharge tube. Excimer irradiation equipment. 2. The excimer irradiation apparatus according to claim 1, wherein the excimer lamps are arranged side by side with a gap of 50 mm or less.