WO2003026361A1

WO2003026361A1 - Dielectric barrier discharger

Info

Publication number: WO2003026361A1
Application number: PCT/JP2002/009081
Authority: WO
Inventors: Tadatomo Ohnoda
Original assignee: Shin-Etsu Engineering Co., Ltd.
Priority date: 2001-09-14
Filing date: 2002-09-06
Publication date: 2003-03-27
Also published as: JP2005196969A; TW569282B

Abstract

A dielectric barrier discharger of high luminous efficiency. Before the start of discharge, an oscillation means (2) sets an oscillation frequency (ft) which facilitates discharge start to start the discharge a lamp (A) by starting from a trigger means (3). Then, a detection means (4) detects the resonance frequency (f2) of a resonance circuit (1) after discharge. A changing means (5) changes an impressed voltage of the voltage output to both electrodes (A1, A2) to the resonance frequency (f2) of a stable discharge region after discharge start.

Description

Description Dielectric barrier discharge device Technical field

The present invention relates to, for example, a dry cleaning apparatus for removing dirt of organic compounds adhering to the surface of a glass substrate such as a liquid crystal display or a silicon semiconductor wafer, and a photochemical reaction with ozone gas in the semiconductor manufacturing process. The present invention relates to a discharge device of a dielectric barrier discharge excimer UV (ultraviolet) lamp which is used for an ashing device for peeling and removing a photoresist which has become unnecessary.

More specifically, a dielectric barrier discharge lamp having a pair of electrodes disposed across a discharge space filled with a discharge gas for generating excimer molecules by dielectric barrier discharge. A UV lamp and a dielectric barrier discharge lamp. The present invention relates to a dielectric barrier discharge device including a power supply device for applying a high frequency voltage between both electrodes of a lamp. Background art

In this type of dielectric barrier discharge lamp, a dielectric exists between a pair of electrodes across a space of a discharge plasma filled with a discharge gas, and the pair of electrodes using this dielectric as a medium is The current will flow by acting as a capacitor.

Even if a high frequency voltage is applied between the pair of electrodes, the resistance of the discharge path is infinite and the capacitor remains as it is before the discharge is started. When energy is applied, discharge begins very easily through the dielectric barrier, and the discharge gas filled in the dielectric barrier is excited. It emits light energy of the wavelength specific to the gas.

Although this dielectric barrier discharge lamp continues discharge with its capacitance characteristics during discharge, its capacitance is increased because the dielectric constant is higher than before discharge is started. However, they have the property that they do not change significantly during discharge.

However, in such a conventional discharge device for a dielectric barrier discharge lamp, since the same high voltage is continuously supplied in the discharge start region without changing the frequency, the luminous efficiency is not sufficient. There is a problem that considerable heat generation is required to obtain light intensity.

Therefore, the inventor of the present application has experimentally found that the resonance circuit including the dielectric barrier discharge lamp has the capacitance of the dielectric barrier discharge lamp before the start of discharge as shown in FIG. In this case, it is difficult to start the discharge even if a high voltage is applied between both electrodes at the resonance frequency in the case where the voltage is applied after reaching a predetermined frequency range, it is extremely easy. I found that the discharge started.

Furthermore, when the discharge is started, the capacitance before the discharge starts changes to a larger capacitance C ₂ , so the resonance frequency fi before the discharge starts to the lower resonance frequency f ₂ I also learned to move.

Therefore, the invention according to claim 1 of the present invention aims to provide a dielectric barrier discharge device having high luminous efficiency.

The invention according to claim 2 is, in addition to the object of the invention according to claim 1, an object of the present invention is to easily detect an oscillation frequency range where discharge is easy to start by a simple operation. Disclosure of the invention

In order to achieve the above-mentioned object, the invention according to claim 1 of the present invention 02 09081

(Iii) a resonant circuit including a dielectric barrier discharge excimer UV lamp, an oscillating means for setting the resonant circuit to an oscillation frequency region which is preset before discharge start of the lamp and which facilitates discharge start. Trigger means for starting in the oscillation frequency range where discharge start is easy, detection means for detecting the resonant frequency of the resonant circuit after discharge start, and stable discharge continuation after discharge start detected by the detection means And changing means for changing the applied voltage to the resonance frequency of

Here, the dielectric valya discharge used as an excitation source of the above-mentioned excimer UV lamp is said to include an aliased ozonizer discharge or a silent discharge (silent discharge) and a high frequency discharge by capacitive coupling as a method of applying a high frequency electric field. There is.

The operation of the invention according to claim 1 resulting from such a configuration is that, in the state before the discharge start, the oscillation means sets the oscillation frequency region in which the discharge start is easy, and the lamp starts by the trigger means. After that, the detection means detects the resonance frequency of the resonant circuit after discharge, and the change means marks the voltage output to both electrodes at the resonance frequency of the stable discharge area after the discharge starts. Change the applied voltage.

The invention according to claim 2 is characterized in that, in the configuration according to the invention according to claim 1, the oscillation frequency range is a frequency range higher than the resonance frequency due to the capacitance of the resonance circuit before lamp discharge measured in advance. It is characterized in that

The operation of the invention according to claim 2 resulting from the configuration thus added makes it possible to easily detect the oscillation frequency range where discharge can be easily started. Brief description of the drawings

FIG. 1 is a circuit diagram of a dielectric barrier discharge device showing one embodiment of the present invention. FIG. 2 is an explanatory view showing a relationship between a voltage between both electrodes and a resonance frequency. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment of the present invention will be described based on the drawings.

In this embodiment, as shown in FIG. 1, a dielectric barrier discharge excimer UV lamp A has an internal electrode A1 disposed along the inner side of a quartz glass discharge vessel A3 formed in a hollow cylindrical shape and is provided on the outer side. An external electrode A2 is disposed along the discharge space of the discharge vessel A3 and xenon gas is enclosed as discharge gas A4 so that excimer VUV (vacuum ultraviolet light) of 17 2 nm radiates radially. It shows the case of a double cylindrical structure.

A feeder B for applying a high frequency voltage between the two electrodes A 1 and A 2 is

And a resonant circuit 1 including a dielectric barrier discharge excimer UV lamp A, and an oscillation means for setting the resonant circuit 1 into an oscillation frequency region f _t which is previously set before the discharge start of the excimer UV lamp A. 2, a trigger 1 means 3 for starting in the oscillation frequency range f _t where the discharge start is easy, a detection means 4 for detecting the resonance frequency of the resonant circuit 1 after the discharge start, and detection means 4 A change means 5 is provided for changing the applied voltage to a resonance frequency for sustaining stable discharge after the start of discharge.

In the case of the present embodiment, the resonance frequency: ^ by the capacitance of the resonance circuit 1 is measured and obtained in advance in a state before the excimer UV lamp A is discharged.

The oscillation means 2 is an oscillation circuit that oscillates an oscillation frequency range f _t which facilitates discharge start higher than the resonance frequency in a state before the discharge start, and its output end is connected to the power amplifier 7 via the addition circuit 6. After being amplified by the power amplifier 7, the signal is output to both electrodes A 1 and A 2 through the resonant circuit 1. The trigger means 2 is a trigger circuit that outputs a discharge start signal in an oscillation frequency range f _t where discharge start by the oscillation means 2 is easy, and its output end is connected to the addition circuit 6, and from the trigger circuit Power amplifier 6 based on the output of The oscillation frequency domain: The voltage of f _t is output to both electrodes A 1 and A 2 via the resonant circuit 1.

The detection means 4 comprises a detection circuit, and a coil is formed by the coil on the input side, the coil connected to the output end of the power amplifier 1b, and the inductance coil of the resonant circuit 1, The inductance L of the resonant circuit 1. At the same time, after the discharge of the excimer UV lamp A is started, for example, after 1 second, the resonance point of the resonance circuit 1 is detected and fed back to the oscillation circuit of the oscillation means 2.

Furthermore, the oscillation circuit of the oscillation unit 2, the resonance point of the resonance circuit 1 is detected by the detection means 4 are fed back, the resonance frequency: ^ lower resonance frequency: switched oscillate f _2, which It is also a changing means 5 for changing the voltage output to both electrodes A 1 and A 2 to the resonance frequency f ₂ for sustaining stable discharge after the start of discharge.

In addition, an attenuator 8 may be connected in the circuit of the power feeding device B, if necessary, to attenuate the signal passing therethrough to an appropriate amount.

Next, the operation of such a dielectric barrier discharge device will be described.

First, the oscillation frequency region: f _t which is easy to start discharge higher than the resonance frequency measured in advance by the oscillation circuit of the oscillation means 2 is set.

In this state, a trigger signal of trigger 1 means 3 outputs a discharge start signal to both electrodes Al and A2, whereby the discharge of the excimer UV lamp A is very easily started.

After this discharge is started, the resonance point of the resonance circuit 1 is detected by the detection means 4 after 1 second, for example, and the oscillation of the oscillation means 2 whose resonance frequency f ₂ lower than the resonance frequency is also the change means 5 is fed back to the circuit, controls the oscillator so that the best resonance frequency f _2.

As a result, the voltage output to both electrodes Al and A2 is stable after the discharge starts. Range of the resonance frequency: changing the voltage applied to f _2.

Stated an example thereof, in the resonant frequency measured in advance e.g. 2.08MHz, approximately 0.2MHz from Re their high about 2. Oscillation frequency range around the 10 MHz: at _t, when to discharge the excimer UV lamp A, excimer UV lamp A does not change the frequency even after the discharge starts, and in order to irradiate excimer VUV with an irradiance of 25 mW / cm ² as it is, about 600 W of power must be input to both electrodes A 1 and A 2 , The reflected power was about 400W.

On the other hand, after the excimer UV lamp A starts to discharge, when the resonance frequency lower than the above oscillation frequency area: f _t (area centered on about 2.10 MHz): f ₂ is changed to 1.80 MHz, for example, In order to irradiate excimer VUV with an irradiance of 25 mW / cm ² , about 200 W of power had to be input to both electrodes A1, A2, and the reflected power was about 70 W.

These differences are differences in the efficiency of converting electrical energy into light energy of excimer V UV.

As a result, the light emission efficiency with respect to the input power is improved, whereby the heat generation can be suppressed even if the desired amount of light is obtained.

The dielectric barrier discharge used as an excitation source for the excimer UV lamp A is also known as an aliaser discharge or silent discharge, and a high frequency discharge by capacitive coupling as a method of applying a high frequency electric field. However, the present invention can be used with either of the discharge methods.

In the above-described embodiment, the dielectric barrier discharge excimer UV lamp A has the internal electrode A1 disposed along the inside of the hollow cylindrical discharge vessel A3 and the external electrode A2 disposed along the outside. The discharge vessel A 3 has a double cylindrical structure in which xenon gas is enclosed as discharge gas A 4, but the invention is not limited thereto. The shape of the discharge vessel A 3 and both electrodes A 1 , A 2 arrangement position and discharge gas A 4 may be different. Industrial applicability

As described above, the invention according to claim 1 of the present invention sets the oscillation frequency range in which the discharge can be easily started by the oscillation means, and the discharge of the lamp is started by the activation from the trigger one means. After that, the detecting means detects the resonant frequency of the resonant circuit after the discharge, and the changing means changes the voltage output to both electrodes to the resonant frequency of the stable discharge region after the discharge is started. It is possible to provide a dielectric barrier discharge device having high luminous efficiency.

Therefore, the heat generation can be suppressed to obtain the desired light intensity, and the energy can be saved accordingly to miniaturize the power supply.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, the resonance frequency due to the capacitance of the resonance circuit is measured in advance in the state before the lamp is discharged. The frequency domain can be easily detected.

Claims

The scope of the claims

1. A dielectric barrier discharge excimer UV lamp (A) in which a pair of electrodes (Al, A2) are disposed across a discharge space filled with a discharge gas (A4) for generating excimer molecules by dielectric barrier discharge A dielectric barrier discharge device comprising a power supply device (B) for applying a high frequency voltage between both electrodes (A 1, A 2) of the dielectric barrier discharge excimer UV lamp (A);

The resonant circuit (1) including the dielectric barrier discharge excimer UV lamp (A), and the discharge circuit wherein the resonant circuit (1) is preset before the discharge of the lamp (A) starts. and start easy oscillation frequency domain oscillation means to (f _t) (2), and the discharge start easy oscillation frequency domain trigger means (3) for starting with (f _t), the discharge start after the resonance A detection means (4) for detecting the resonance frequency (f ₂ ) of the circuit (1) and a voltage applied to the resonance frequency (f ₂ ) for sustaining a stable discharge after the discharge start detected by the detection means (4) And a change means (5) for changing the dielectric barrier discharge device.

2. The oscillation frequency region (f _t ) is the capacitance of the resonance circuit (1) before lamp discharge measured in advance, which is a frequency region higher than f j (resonance frequency according to C 1. Discharge device.