JP3314656B2 - Light source device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device having a dielectric barrier discharge lamp.

[0002]

2. Description of the Related Art In recent years, an object to be processed made of metal, glass, or another material is irradiated with ultraviolet rays, whereby the object to be processed is treated by the action of the ultraviolet rays and ozone generated thereby. A cleaning technology for removing organic contaminants adhering to the surface of a body and an oxide film forming technology for forming an oxide film on the surface of a body to be processed have been developed and put into practical use.

In such a light source device for processing ultraviolet rays, a low-pressure mercury lamp which emits ultraviolet rays having a wavelength of 185 nm, which is a resonance line of mercury, has conventionally been used as a light source for emitting ultraviolet rays. In a discharge vessel, an appropriate discharge gas is filled in a discharge vessel partly composed of a dielectric, and a dielectric barrier discharge (also known as “ozonizer discharge” or “silent discharge”) is formed in the discharge vessel.
New edition "Discharge Handbook" published by the Institute of Electrical Engineers of Japan, June 2001
See page 263 of the 7th reprint of the month. ), A dielectric barrier discharge lamp has been developed in which excimer is generated and excimer light is emitted. For example, Japanese Patent Application Laid-Open No. 1-144560 discloses a dielectric barrier discharge lamp in which a discharge gas is filled in a hollow cylindrical discharge vessel at least partially composed of quartz glass which is a dielectric. ing.

In such a dielectric barrier discharge lamp, for example, by using xenon gas as a discharge gas, ultraviolet light having a peak at a wavelength of 172 nm, which is excimer light by xenon excimer, is emitted. For example, it is known that by using a mixed gas of argon and chlorine gas, ultraviolet light having a peak at a wavelength of 175 nm, which is excimer light by argon-chlorine excimer, is emitted.

As a light source device having a dielectric barrier discharge lamp, Japanese Patent Laid-Open No. 5-174793 discloses a cylindrical dielectric barrier discharge lamp housed in a casing having a window member for extracting excimer light. What is done is described.

However, in such a light source device,
Since excimer light from the dielectric barrier discharge lamp is absorbed by oxygen present in the casing, excimer light from the dielectric barrier discharge lamp cannot be extracted to the outside from the window member of the casing with high efficiency. Therefore, the concentration of oxygen present in the casing is reduced by flowing an inert gas through the casing.

[0007]

However, the above light source device has the following problems. For an object to be processed having a large size, it is necessary to use a large light source device. However, in the case of a large light source device, it is necessary to maintain the concentration of oxygen remaining in the casing at an expected level even when the inert gas is circulated at the same flow rate in the casing as compared with the small light source device. Is difficult. In order to maintain the concentration of oxygen remaining in the casing at a desired level, it is necessary to increase the gas pressure in the casing or to increase the flow rate of the inert gas. If the pressure is increased unnecessarily, the window member of the casing may be damaged.Therefore, a window member having a large thickness capable of withstanding the considerably high gas pressure must be used. On the other hand, if the flow rate of the inert gas is excessively increased, there is a problem that the processing cost of the object to be processed increases.

The present invention has been made in view of the above circumstances, and when the gas pressure in a cane sig is equal to or higher than a specific value, the concentration of oxygen remaining in the casing is substantially constant. The present invention was completed based on this finding. SUMMARY OF THE INVENTION An object of the present invention is to provide a light source device in which the concentration of oxygen remaining in a casing is stably maintained at a desired level, and can emit excimer light from a dielectric barrier discharge lamp with high efficiency. is there.

[0009]

A light source device according to the present invention accommodates a dielectric barrier discharge lamp in which excimer is generated by dielectric barrier discharge and excimer light is emitted, and the dielectric barrier discharge lamp is housed therein. In a light source device comprising: a casing having a window member for extracting excimer light from a dielectric barrier discharge lamp; and gas flowing means for flowing an inert gas into the casing, the gas flowing means includes: An inert gas is circulated in the casing such that the gas pressure is at least 100 Pa greater than the atmospheric pressure.

In the light source device according to the present invention, when the gas pressure in the casing becomes less than 100 Pa greater than the atmospheric pressure, the operation of the dielectric barrier discharge lamp is stopped and the flow of the inert gas is stopped. Preferably, means are provided. Further, it is preferable to provide an alarm means for alarming when the gas pressure in the casing becomes less than a value larger than the atmospheric pressure by 100 Pa.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a light source device according to the present invention will be described in detail. FIG. 1 is a schematic diagram showing the outline of the configuration of an example of the light source device of the present invention. In this figure,
Reference numeral 10 denotes a dielectric barrier discharge lamp that generates excimer light by dielectric barrier discharge and emits excimer light.
Connected to 0. Reference numeral 20 denotes a casing that houses the dielectric barrier discharge lamp 10. Reference numeral 30 denotes a gas distribution unit that distributes an inert gas into the casing 20. The gas distribution unit 30 includes a gas supply source 31, a gas supply solenoid valve 32, and a gas discharge adjustment valve 33. The solenoid valve 32 is connected to the control power supply 40. 35
Is a gas pressure detector for detecting the gas pressure in the casing 20, and this gas pressure detector 35 is
Connected to 0. An alarm 36 is activated by a signal from the control power supply.

FIG. 2 is an explanatory sectional view showing the casing 20 of the light source device shown in FIG. 1 and the internal structure thereof.
In this example, in a rectangular box-shaped casing 20,
Four dielectric barrier discharge lamps 10 are housed.

More specifically, the casing 20 is provided with a box-shaped frame member 21 having an opening 22 on the lower surface and having a rectangular shape as a whole. A window member 23 for taking out light from the discharge lamp 20 to the outside is provided. Further, a gas introduction hole 24 for introducing an inert gas into the casing 20 is formed on one side surface of the frame member 21, and the gas inside the casing 20 is discharged on the other side surface of the frame member 21. A gas discharge hole 25 is formed. As a material for forming the window member 13, a material having transparency to excimer light from the dielectric barrier discharge lamp 10, for example, synthetic quartz glass can be used.

A cooling block 26 made of aluminum is provided at an upper portion in the casing 20. On the lower surface of the cooling block 26, four grooves 27 each having a semicircular cross section having a diameter larger than the outer diameter of the dielectric barrier discharge lamp 10 are formed so as to be spaced apart from each other. A dielectric barrier discharge lamp 10 is arranged along each of the above. 28 is a cooling block 26
Is a cooling fluid flow passage formed to penetrate through and through which the cooling fluid flows. In the illustrated example, a light reflecting plate 29 made of aluminum and having a V-shaped cross section is provided at a position between the adjacent grooves 27 on the lower surface of the cooling block 26.

In the dielectric barrier discharge lamp 10,
As shown in FIG. 3, a hollow cylindrical discharge vessel 11 is provided. More specifically, the discharge vessel 11 includes a cylindrical wall portion 12 made of a dielectric and one of the wall members 12 disposed inside the one wall member 12 along the cylinder axis. The other wall member 13 made of a dielectric material having an outer diameter smaller than the inner diameter, and both ends of the one wall member 12 and the other wall member 13 are joined by a sealing wall portion 14 to form one wall. A cylindrical discharge space S is formed between the material 12 and the other wall material 13. A discharge gas is sealed in the discharge vessel 11.

One of the wall members 12 of the discharge vessel 11 is provided with one mesh-like electrode 16 made of a conductive material such as a wire mesh in close contact with an outer surface 15 thereof. 13 is provided with a film-shaped other electrode 18 made of aluminum so as to cover an outer surface 17 which is an inner peripheral surface thereof.

In the example shown in the figure, a deformed portion 19 is formed at one end of one wall member 12 constituting the discharge vessel 11 so as to protrude inward along the circumferential direction.
A getter accommodating chamber K communicating with the discharge space S is formed between the deformed portion 19 and the sealing wall section 14 on one end side, and a getter G made of, for example, a barium alloy is accommodated in the getter accommodating chamber K. I have. The getter G is heated by, for example, high frequency, so that a thin film made of barium is formed on the inner wall surface of the getter accommodating chamber K.

The dielectric material constituting the one wall member 12 and the other wall member 13 in the discharge vessel 11 is a dielectric material which transmits excimer light emitted in the discharge vessel 11, for example, synthetic quartz glass. Can be used. As the discharge gas sealed in the discharge vessel 11, for example, xenon gas, a mixed gas of argon and chlorine, or the like can be used.

In the light source device of the present invention, the inert gas is circulated in the casing 20 by the gas circulating means 30 so that the gas pressure in the casing 20 becomes a value greater than the atmospheric pressure by 100 Pa or more. When the dielectric barrier discharge lamp 10 operates, the workpiece W
Is subjected to a required light irradiation process.

Specifically, when the control power supply device 40 is operated, the gas supply solenoid valve 32 is opened, so that the gas supply source 31 is connected to the casing 20 through the gas supply hole 24.
The gas in the casing 20 is discharged to the outside through the gas discharge hole 25 and the gas discharge adjusting valve 33 while the inert gas is supplied to the inside. Thereafter, when the gas pressure detector 35 detects that the pressure of the inert gas in the casing 20 has reached a value greater than the atmospheric pressure by 100 Pa, the control power supply device 40 supplies high-frequency power to the dielectric barrier discharge lamp 10. Is done. In the dielectric barrier discharge lamp 10, a voltage is applied between one electrode 16 and the other electrode 18,
A dielectric barrier discharge is generated in the discharge space S in the discharge vessel 11, thereby generating excimers due to the elements constituting the filling gas, and excimer light generated by the excimers passes through one wall member 12 to one electrode. The excimer light radiated from the mesh 16 is transmitted to the window member 2 of the casing 20.
The object to be processed W is irradiated through the substrate 3.

In the above, the dielectric barrier discharge lamp 1
0, the gas pressure detector 35 is
When it is detected that the pressure of the inert gas in the chamber has become less than a value greater than the atmospheric pressure by 100 Pa, the control power supply 4
By 0, the operation of the dielectric barrier discharge lamp 10 is stopped, the gas supply solenoid valve 32 is closed, and the signal from the control power supply 40 causes the alarm 36
Operates. On the other hand, during the operation of the dielectric barrier discharge lamp 10, the gas pressure detector 35 detects that the pressure of the inert gas in the casing 20 is 1.
When it is detected that the value exceeds 3 kPa, the operation of the dielectric barrier discharge lamp 10 is stopped by the control power supply 40, the gas supply solenoid valve 32 is closed, and a signal from the control power supply 40 is output. Thereby, the alarm 36 operates.

According to such a light source device, the inert gas is circulated in the casing 20 by the gas circulating means 30 so that the pressure in the casing 20 becomes greater than the atmospheric pressure by 100 Pa or more. As is clear from the experimental example, the concentration of oxygen remaining in the casing 20 is stably maintained at a desired level. Therefore, the excimer light from the dielectric barrier discharge lamp 20 is
The excimer light from the dielectric barrier discharge lamp 20 can be emitted to the outside of the casing 20 with high efficiency as a result.

When the gas pressure in the casing 20 becomes less than a value greater than the atmospheric pressure by 100 Pa, the operation of the dielectric barrier discharge lamp 10 is stopped by the control power supply device 40 and the gas supply solenoid valve 32 is turned off. Is closed and the flow of the inert gas is stopped.
It is possible to reliably prevent the light irradiation processing of the processing target object W from being performed in a state where the concentration of oxygen remaining in 0 is high. In addition, the gas pressure in the casing 20 is lower than the atmospheric pressure by one.
When the value becomes smaller than 00 Pa, the alarm 36 is activated, so that the worker can be notified that the concentration of oxygen remaining in the casing 20 has increased.

When the gas pressure in the casing 20 exceeds a specific value, for example, a value 1.3 kPa larger than the atmospheric pressure, the control power supply device 40 closes the gas supply solenoid valve 32 to release the inert gas. Distribution will be suspended,
It is possible to reliably prevent the window member 23 of the casing 20 from being damaged.

<Experimental Example> A dielectric barrier discharge lamp was manufactured according to the configuration shown in FIG. 3 under the following conditions. Discharge vessel (11): total length 300 mm, one wall (12): material; synthetic quartz glass, outer diameter: 2
6.5 mm, wall thickness: 1 mm, other wall (13): material: synthetic quartz glass, outer diameter: 1
6.0 mm, thickness: 1 mm, one electrode (16): stainless steel wire mesh, the other electrode (18): aluminum, discharge gas: xenon (filling pressure: 30 kPa)

The above-mentioned dielectric barrier discharge lamp is supplied with an input power of about 50 kHz by a high-frequency power supply having a frequency of about 20 kHz.
When the lamp was turned on under the condition of W, light having a peak at a wavelength of 172 nm was emitted.

According to the configuration shown in FIG. 2, four of these dielectric barrier discharge lamps were sized to 450 mm × 350 mm.
Placed in a × 100 mm casing (20),
As shown in FIG. 4, the casing (20) is connected to a nitrogen gas supply source (50) via a gas flow meter (51), and connected to a gas discharge regulating valve (52). An experimental system for examining the relationship between the gas pressure in the casing and the concentration of oxygen remaining in the casing by arranging the gas pressure gauge (53) and the oxygen concentration meter (54) in 20). did.

Then, 10 liter / minute and 30 liter / minute from the nitrogen gas supply source (50) into the casing (20).
By supplying nitrogen gas at a flow rate of 50 liters / minute and 50 liters / minute, the nitrogen gas is allowed to flow through the casing (20), and by adjusting the gas discharge adjusting valve (52), the inside of the casing (20) is adjusted. The concentration of oxygen remaining in the casing (20) when the gas pressure was varied was measured. FIG. 5 shows the results. In this figure,
The horizontal axis indicates the gas pressure in the casing, and the vertical axis indicates the concentration of oxygen remaining in the casing. Also, the curve (a)
Shows a case where nitrogen gas was supplied at a flow rate of 10 liter / min, a curve (b) shows a case where nitrogen gas was supplied at a flow rate of 30 liter / min, and a curve (c) shows a case where nitrogen gas was supplied at 50 liter / min. The case where the flow rate is supplied at a flow rate of 1 / min is shown.

As apparent from FIG. 5, the gas pressure in the casing is changed from the atmospheric pressure to the lower pressure regardless of the flow rate of the nitrogen gas, 10 liter / minute, 30 liter / minute and 50 liter / minute. Until the gas pressure increases, the concentration of oxygen remaining in the cane sig rapidly decreases until the gas pressure increases by 100 Pa, and the gas pressure in the casing becomes 100 P
When the gas pressure is larger than a, regardless of the value of the gas pressure,
It is understood that the concentration of oxygen remaining in the cane sig is maintained at a substantially constant value. Therefore, the flow rate of the inert gas supplied into the casing is selected, and the inert gas is circulated through the casing so that the gas pressure in the casing becomes a value greater than or equal to the atmospheric pressure by 100 Pa or more. The concentration of the remaining oxygen can be stably maintained at a desired level.

[0030]

According to the present invention, the inert gas is circulated in the casing by the gas circulating means so that the pressure in the casing becomes 100 Pa or more higher than the atmospheric pressure. Oxygen concentration is maintained stably at the desired level. Therefore, it is possible to reliably suppress the excimer light from the dielectric barrier discharge lamp from being absorbed in the cane sig. As a result, the excimer light from the dielectric barrier discharge lamp is radiated to the outside of the casing with high efficiency. be able to.

Further, when the gas pressure in the casing becomes less than a value larger than the atmospheric pressure by 100 Pa, a control means for stopping the operation of the dielectric barrier discharge lamp and the gas flow means is provided, so that the gas remains in the casing. It is possible to reliably prevent the light irradiation treatment of the object to be processed in a state where the concentration of oxygen is high. In addition, by providing an alarm unit that operates when the gas pressure in the casing becomes less than a value greater than the atmospheric pressure by 100 Pa, it is possible to notify an operator that the concentration of oxygen remaining in the casing has increased. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an example of a light source device of the present invention.

FIG. 2 is an explanatory sectional view showing a casing of the light source device shown in FIG. 1 and a configuration inside the casing.

FIG. 3 is an explanatory sectional view showing a configuration of an example of a dielectric barrier discharge lamp used in the present invention.

FIG. 4 is a schematic diagram showing an outline of an experimental system for examining a relationship between a gas pressure in a casing and a concentration of oxygen remaining in the casing.

FIG. 5 is a curve diagram showing a relationship between a gas pressure in a casing and a concentration of oxygen remaining in the casing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Dielectric barrier discharge lamp 11 Discharge container 12 One wall part 13 The other wall part 14 Sealing wall part 15 Outer surface of one wall part 16 One electrode 17 Outer surface of the other wall part 18 The other electrode 19 Deformation part 20 Casing 21 Frame material 22 Opening 23 Window member 24 Gas supply hole 25 Gas exhaust hole 26 Cooling block 27 Groove 28 Cooling fluid flow passage 29 Light reflecting member 30 Gas distribution means 31 Gas supply source 32 Gas supply solenoid valve 33 Gas discharge Control valve 35 Gas pressure detector 36 Alarm device 40 Control power supply device 50 Nitrogen gas supply source 51 Gas flow meter 52 Gas discharge control valve 53 Gas pressure gauge 54 Oxygen meter G Getter K Getter storage chamber S Discharge space W Target object

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-8-124536 (JP, A) JP-A-8-96770 (JP, A) JP-A-7-196303 (JP, A) (58) Field (Int. Cl. ⁷ , DB name) H01J 65/04 G21K 5/00

Claims (3)

(57) [Claims] 1. A dielectric barrier discharge lamp in which excimer is generated by a dielectric barrier discharge to emit excimer light, an excimer light is housed in the dielectric barrier discharge lamp, and excimer light from the dielectric barrier discharge lamp is taken out. In a light source device comprising: a casing having a window member; and gas distribution means for flowing an inert gas through the casing, the gas pressure in the casing is at least 100 Pa greater than atmospheric pressure by the gas distribution means. A light source device characterized in that an inert gas flows through the casing. 2. The gas pressure in the casing is lower than the atmospheric pressure by one.
2. The light source device according to claim 1, further comprising a control unit that stops the operations of the dielectric barrier discharge lamp and the gas flow unit when the pressure becomes less than 00 Pa. 3. 3. The gas pressure in the casing is lower than the atmospheric pressure by one.
The light source device according to claim 1, further comprising an alarm unit that is activated when the value becomes smaller than 00 Pa.