JPH0343951A - Short wavelength light and ultraviolet ray generating apparatus - Google Patents

Abstract

PURPOSE:To prevent temperature increase owing to discharge of a discharge gas and make it possible to take out a specific and desired line spectrum by installing a gas discharging nozzle in the position where a microwave transmitted through a glass diaphragm and the discharge gas emit light by electric discharge in the periphery of the glass diaphragm of a gas discharge space. CONSTITUTION:A gas discharge nozzle 4 is installed in the position where a microwave 8 transmitted through a glass diaphragm 6 and a discharge gas emit light in the periphery of the glass diaphragm 6 in a gas discharge space 5. In this way, imbalance of discharge luminance 9 owing to the distribution of the microwave is prevented, and light radiation distribution to the plane to be irradiated becomes uniform in a larger surface area. Since the gas discharge nozzle 4 is placed in the proper position, the electric discharge is carried out not in a highly vacuum part 2 but in the space where the gas is discharged and light emission occurs in the periphery of the side of the glass diaphragm 6 having enough resistance to gas electric discharge energy and thus deterioration of a window 7 which transmits short wavelength light emitted by electric discharge is prevented. By this method, temperature increase owing to the electric discharge of a diacharge gas is prevented and a line spectrum with constant radiation intensity and wavelength can be taken out.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a short wavelength ultraviolet light generating device, and in particular,
SiH by light energy from 0nm to 190nm
Generation of high quality α-3i:HF2 film using 4 gases,
This field relates to applications to optical devices, ultra-high vacuum technology based on the decomposition and separation of H20 molecules in ultra-high vacuum containers, materials based on substances and their interactions, and the development of fundamental technologies such as life science.

[Conventional technology]

Microwave discharge has been variously studied as a form of electric discharge. This discharge is an electrodeless discharge, and has characteristics not found in electroded discharges, such as energy being injected from the periphery of the discharge tube, and is characterized by the following points.

(1) Medium freedom: The plasma generation medium can be freely selected without considering the reaction with the electrode, and there is no plasma contamination.

(2) Long life: There is no deterioration of JJ Bunden electric tubes due to scattering of electrode materials.

(3) Spreading of discharge: The discharge is not concentrated in one part and spreads easily, and the light emission is strong near the wall of the discharge tube.

(4) Simple configuration: There are no electrodes in the discharge tube, and no discharge stabilization element is required in the power supply.

Various vacuum ultraviolet light sources using microwave discharge that take advantage of these characteristics have been proposed.

For example, Japanese Patent Publication No. 55-35825 (U.S. Pat.
As disclosed in Japanese Patent Publication No. P 390659, etc., there is a technology that confines microwaves in a certain space and confines desired gases and metals in a quartz bulb, which is high melting point glass, to emit light. (See Figure 6).

Also, IEEE, 1987 MATUNA Gate 1.
Like the vacuum ultraviolet light source published in the paper by FUYUKI, a quartz gas discharge tube 42 is placed on the H plane in a rectangular waveguide 41 (see Figure 7), and the axial direction of the discharge tube 42 is A rare gas GAS is discharged while flowing, and a short wavelength transmitting window material 4 such as magnesium fluoride (MgFz) is attached to one end of the discharge tube 42.
There is also a technique for extracting light energy with a wavelength of around 140 nm by providing a wavelength of approximately 140 nm.

Furthermore, the pH of Illumination Society of Japan Study Group L S-87-1 ~ P1
In the cylindrical cavity resonator 52 (see Fig. 8), as in the "vacuum ultraviolet light source using microwave discharge" announced in 1997,
There is also a technique of arranging a cylindrical electrodeless discharge tube 54 (for example, using sapphire with an outer diameter of 10 mm) and extracting the entire emitted light.

[Problem to be solved by the invention]

By the way, since the plasma light emitting light source device disclosed in Japanese Patent Publication No. 55-35825 uses a quartz material as the arc tube 32, it does not allow light with a wavelength below the short wavelength transmission limit of the quartz material (about 160 nm for synthetic quartz). There was a lesson that there was no way to take it out.

Also, IEEE, 1987 M to T [INAMI, F
In the vacuum ultraviolet light source published in UYUKI's paper, the plasma region changes depending on the microwave power. For this reason, it is difficult to increase the plasma power density, and it is also difficult to increase the area, and the practical diameter is about 30 mm. In addition, since plasma discharge is used, there is a problem that the window material deteriorates quickly.

In addition, the vacuum ultraviolet light source using microwave discharge, which was announced in the Illuminating Engineers of Japan Study Group LS-87-1, pH ~ P17, is placed in a vacuum, so there is no way to cool the heat by emitting light, and there is no natural cooling. However, there is a limit to inputting an incident power above a certain level, and microwave power of 100
W was the limit.

From the above, it is an object of the present invention to have a window material that enables light irradiation over a large area with a diameter of 80 mm or more, to prevent deterioration of the window material, and to allow discharge gas to always flow at a constant pressure and flow rate. An object of the present invention is to provide a short-wavelength ultraviolet light generating device that prevents a temperature rise due to discharge of a discharge gas, extracts a spectral line with a constant radiation intensity and wavelength, and makes it possible to input high-power microwave power.

[Means and effects for solving the problems] In order to solve the above problems, the short wavelength ultraviolet light generating device of the present invention includes a waveguide section 1 and an example of this waveguide section, as shown in FIG. a high vacuum section 2 that is sealed and separated from the atmosphere and has a high-resistance vacuum layer; and an antenna section 3 that is located within the high vacuum section 2 and radiates microwaves 8 from the waveguide section 1 side. , a gas discharge space 5 which is adjacent to the high vacuum part 2 and is formed by sealing a discharge gas that emits light in response to microwaves 8 through a gas discharge nozzle 4; and this gas discharge space 5 and the high vacuum part 2. a glass partition wall 6 made of a glass material that is transparent to the microwave 8 and impermeable to the discharge gas;
A short-wavelength light transmitting window material 7 that emits short-wavelength light 9 is provided on the opposite side of the glass partition wall 6 and the gas discharge space 5, and microwaves transmitted through the glass partition wall 6 are formed. The gas discharge nozzle 4 was disposed at a position where the gas discharge nozzle 8 discharged light in the vicinity of the glass partition wall 6 in the gas discharge space 5 with the discharge gas.

As a result, non-uniformity of the discharge light emission 9 due to the distribution of microwaves can be prevented, and the distribution of light irradiated onto the illuminated side surface becomes uniform over a larger area.

In addition, since the gas discharge nozzle 4 was installed at an appropriate position,
The discharge is not on the high vacuum section 2 side, but on the space section 5 where the gas is released.
In addition, discharge light can be emitted in a space close to the glass partition wall 6 side, which is sufficiently resistant to gas discharge energy, and deterioration of the short wavelength light transmitting window material 7 due to discharge can be prevented.

〔Example〕

Hereinafter, the short wavelength ultraviolet light generating device of the present invention will be explained based on the drawings.

FIG. 2 is a schematic explanatory diagram of a short wavelength ultraviolet light generating device which is an embodiment of the present invention.

11 is a microwave generator (magnetron), 12 is a circulator, 13 is a power monitor, 14 is an input-stub tuner, 15 is a waveguide exchanger that converts a large waveguide into a circular waveguide, 16 is a Xe .

17a and 17b are exhaust ports, and 18 is a gas flow controller (MFC) to a gas cylinder that supplies gases such as An, D2, He, etc. for the discharge tube section (gas discharge space section).

For example, microwaves of 2450 MHz are generated in the magnetron 11 and supplied to the waveguide exchanger 15 through a large waveguide. Since the magnetron 11 is operated by a full-wave rectified power supply, the microwaves generated are 100
It is a pulsating flow of Hz or 120 H2.

FIG. 3 is an explanatory diagram of the main parts of this short wavelength ultraviolet light generator. In addition, in FIG. 3, a high vacuum section 2, a microwave radiation antenna 3, a gas discharge nozzle 4, a gas discharge space section 5, a quartz glass partition wall 6, a short wavelength light transmission window material 7, a radiation electromagnetic field (microwave) 8, The same symbols as in FIG. 1 are used for the vacuum ultraviolet light 9 and the ceramic window 10. In addition, the exhaust port 17a
The same reference numerals as in FIG. 2 are used for 17b.

Cooling water ports 21a and 21b cool the heat generated by light emission. 23 is a discharge gas supply port, and 24 is a stainless steel arc tube holder.

Note that when microwave discharge is applied to a light source, it is necessary to use a short wavelength light transmitting window material 7 in the portion where light is extracted from the discharge. In this example, for example, magnesium fluoride (
An electrodeless discharge tube is formed using the M g F 2 ) window shed 7. When this magnesium fluoride is used, the light transmission characteristic of the short wavelength light transmission window material 7 can transmit up to around 120 nm.

The high vacuum side of the high vacuum section 2 is preferably 10-' Torr or more. At 10-1 to 10-2 Torr, discharge occurs due to residual atmosphere, the radiated electromagnetic field 8 is absorbed, and no effective radiated electromagnetic field 8 is supplied to the gas discharge space 5 side.

In this embodiment, the quartz glass partition wall 6 is substantially integrated with the short wavelength light transmitting window material 7, and also serves as the discharge tube section 5.

The gas discharge nozzle 4 is made of quartz glass and has a discharge gas supply port 23.
It is inserted into. And by being inserted,
This prevents microwave discharge from occurring in the metal parts of the stainless steel arc tube holder 24.

Further, the gas discharged from the gas discharge nozzle 4 is once blown onto the short wavelength light transmitting window material 7 side.
After being cooled, it is exhausted from the exhaust port 17b. Due to this gas circulation, the discharge occurs in the space 5 where the gas is released.
In addition, the discharge light can be caused to emit light in a space close to the glass partition wall 6 side, which is sufficiently resistant to gas discharge energy, and deterioration of the short wavelength light transmitting window material 7 due to discharge can be prevented.

Next, the vacuum ultraviolet emission characteristics of the xenon (Xe) gas used in this example will be explained.

Xenon gas has a resonance line of 147 nm and is often used as a vacuum ultraviolet light source. The spectrum of the 147 nm line when the discharge tube section 5 of this example is used will be explained. Figure 4 shows the 147nm I! when xenon (99,995%) was used as the discharge gas and the discharge pressure was varied from 0.1 Torr to 10 Torr. This shows the rS line profile. Note that the gas flow rate is 20 cc/min, P
A discharge experiment was conducted at i=0.5Kw and Pr=005Kw.

In addition, ACTON VM-502 is used as a measurement spectrometer.
ACTON DA-780-VUV was used. Furthermore,
At this time, the slit width was 0.25 mm, and the slit length was 4.
mm, and the measurement distance is 69 cm.

As shown in FIG. 4, the higher the pressure, the lower the peak of the spectrum. Since inversion absorption occurs at 10 Torr, it is thought that this is largely due to self-absorption.

FIG. 5 is an illuminance distribution diagram when xenon gas is 0.85 Torr. Note that Z) measures the illuminance distribution of this light emission.
250 n when xenon gas is 0.85 Torr
The luminescence intensity around m was measured using an ultraviolet light meter Ul-
MO2 was used. This illuminance distribution made it possible to obtain the intensity ratio at a diameter of 80 mm.

As a result, if the short wavelength ultraviolet light generator of the present invention is used, a practically sufficient intensity ratio can be obtained.

[Effects of the Invention] According to the present invention, the antenna part that radiates electromagnetic waves is of a sealed type separated from the atmospheric part of the waveguide part, and has a diameter of 80 mm.
It has a window material that enables light irradiation over a large area, and
Since the window material is prevented from deteriorating and the discharge gas is configured to always flow at a constant pressure and flow rate, temperature rise due to discharge of the discharge gas is prevented and a certain desired spectral line can be extracted.

That is, the emission wavelength can be selected by changing the type and pressure of the gas. In addition, it becomes possible to input a large amount of microwave power.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the short wavelength ultraviolet light generator of the present invention,
Fig. 2 is an overall view of a short wavelength ultraviolet light generator which is an embodiment of the present invention, Fig. 3 is an explanatory diagram of the main parts of this short wavelength ultraviolet light generator, and Fig. 4 is a diagram of the 147 nm resonance line of xenon gas. FIG. 5 is an illuminance distribution diagram when xenon gas is at 0.85 Torr, and FIGS. 6 to 8 are schematic explanatory diagrams of a conventional short wavelength ultraviolet light generator. 1... Waveguide, 2... High vacuum section, 3...
・Antenna part, 4... Gas discharge nozzle, 5...
・Gas discharge space part, 6...Glass partition, 7...Short wavelength light transmitting window material, 8...Microwave, 9...Discharge light emission, 11...
・Magnetron, 12...Zerkyracer 14...
- Three stub tuner, 19... vacuum chamber.

Claims (1)

[Claims] A waveguide section and the atmosphere on the side of the waveguide section are separated and sealed, and a high vacuum section having a high-resistance vacuum layer is provided. an antenna section that radiates microwaves from the tube section side; a gas discharge space section that is adjacent to the high vacuum section and is formed by sealing discharge gas that emits light in response to microwaves through a gas discharge nozzle; and this gas discharge space section. It is located at the boundary between the area and the high vacuum area, and is transparent to microwaves.
and a glass partition wall made of a glass material that is impermeable to the discharge gas, and a short-wavelength light-transmissive window material that emits short-wavelength light, located on the opposite side sandwiching the glass partition wall and the gas discharge space. The short-wavelength ultraviolet light generating device is characterized in that the gas discharge nozzle is disposed at a position where the microwave transmitted through the glass partition causes discharge light emission between the discharge gas and the vicinity of the glass partition in the gas discharge space. .