JP2002058995A - Plasma treating device and plasma treating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma treating device capable of reducing a cost, enhanc ing plasma density and the ability. SOLUTION: The space between electrodes 2 and 3 arranged to face each other is formed as a discharge space 34. The discharge space 34 side of at least one electrode 2 (or electrode 3) of the electrodes 2 and 3 arranged to face each other is provided with a dielectric substance 32. This plasma treating device generates a dielectric substance barrier discharge in the discharge space 34 at the pressure near to atmospheric pressure by supplying plasma-forming gas to the discharge space 34 and impressing voltage between the electrodes 2 and 3. The waveform of the voltage to be impressed between the electrodes 2 and 3 is specified to an alternating voltage waveform having no quiescent time and the rising time of the alternating voltage waveform is confined to <=100 μsec.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to cleaning of foreign substances such as organic substances present on the surface of an object to be processed, peeling of resist, improvement of adhesion of an organic film, reduction of metal oxide,
The present invention relates to a plasma processing apparatus for generating plasma used for plasma processing such as film formation and surface modification, and a plasma processing method using the same. Particularly, the present invention relates to a surface of an electronic component requiring precise bonding. It is applied to cleaning and the like.

[0002]

2. Description of the Related Art Conventionally, a glow discharge is stably generated under atmospheric pressure by applying a voltage between electrodes arranged opposite to each other, and a plasma obtained by the glow discharge is used to generate a glow discharge on a substrate such as a wiring board. Processing is taking place. For example, JP-A-2-15171, JP-A-3-241739 or JP-A-1-306569 disclose that a pair of electrodes is provided in a discharge space in a reaction vessel and at least one of the electrodes is located on the discharge space side. A dielectric is placed on the surface and H
The discharge space is filled with a plasma generation gas mainly composed of a rare gas such as e (helium) or Ar (argon), and an alternating voltage is applied between the electrodes to generate plasma of the plasma generation gas. There is disclosed a method of treating an object to be treated placed therein with the plasma.

However, this method has a problem that it is difficult to perform plasma processing only on a specific region of the object to be processed, and that a long processing time is required. Therefore, it has been proposed to perform plasma processing by spraying a plasma jet (particularly, active species of plasma) generated by glow discharge under atmospheric pressure on an object to be processed. JP-A-4-358076, JP-A-3-219082, JP-A-4-212253
Various methods are disclosed in Japanese Unexamined Patent Application Publication No. Hei 6-108257 and the like.

In the above-described plasma processing method, as one method for stably generating a glow discharge under atmospheric pressure, a plasma generating gas containing a large amount of He is introduced into a discharge space. . Further, as another method for stably generating glow discharge under atmospheric pressure, power supplied to a discharge space is reduced. Further, as another method for stably generating a glow discharge under atmospheric pressure, Japanese Patent Application Laid-Open No. H10-154598 discloses a method in which a pulsed voltage is applied between electrodes using a special pulse power supply. A method of performing plasma processing by stably generating glow discharge under atmospheric pressure without using He is disclosed.

[0005]

However, as described above,
In the method of introducing a plasma-generating gas containing a large amount of He into the discharge space, expensive He is indispensable, and there is a problem that the cost (running cost) required for plasma processing is increased. In addition, in the method of reducing the electric power supplied to the discharge space, the generation of arc can be suppressed and the damage to the processing object can be prevented, but the density of the generated plasma is reduced and the plasma processing is not performed. There was a problem of low ability. Further, Japanese Unexamined Patent Application Publication No. 10-15
According to the method described in Japanese Patent No. 4598, plasma treatment can be performed without using He, but since a pulse-like voltage is applied between the electrodes using a special pulse power supply, the glow discharge generated in the discharge space is reduced. This results in a pulse-like discharge (pulse discharge), which causes a pause time of the discharge. As a result, the temporal average value of the plasma density becomes low and the plasma processing ability is low. there were.

[0006] The present invention has been made in view of the above points, and uses a dielectric barrier discharge to provide He.
Is not required, so that the cost of plasma processing can be kept low, and the power input to the discharge space can be increased, the plasma density can be increased, and the plasma processing ability can be increased. It is an object of the present invention to provide a plasma processing apparatus and a plasma processing method that can perform the above-described processes.

[0007]

According to a first aspect of the present invention, there is provided a plasma processing apparatus in which a space is formed between electrodes 2 and 3 facing each other as a discharge space 34, and electrodes 2 and 3 facing each other are formed.
At least one of the electrodes 2 (or the electrode 3) is provided with a dielectric 32 on the discharge space 34 side, a plasma generating gas is supplied to the discharge space 34, and a voltage is applied between the electrodes 2 and 3 to adjust the atmospheric pressure. In a plasma processing apparatus that generates a dielectric barrier discharge in the discharge space 34 under a nearby pressure, the voltage applied between the electrodes 2 and 3 has an alternating voltage waveform having no pause and a rising time of the alternating voltage waveform. Is set to 100 μsec or less.

In the plasma processing apparatus according to a second aspect of the present invention, the space between the opposed electrodes 2 and 3 is formed as a discharge space 34, and at least one of the electrodes 2 and 3 ( Alternatively, a dielectric 32 is provided on the discharge space 34 side of the electrode 3), a plasma generating gas is supplied to the discharge space 34, and a voltage is applied between the electrodes 2 and 3 so that the discharge space 34 is maintained under a pressure near the atmospheric pressure. In the plasma processing apparatus for generating a dielectric barrier discharge, the voltage applied between the electrodes 2 and 3 is changed to an alternating voltage waveform having no pause, and the fall time of the alternating voltage waveform is set to 100.
μsec or less.

According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the repetition frequency of the alternating voltage waveform is set to 0.5 to 200 kHz. is there.

According to a fourth aspect of the present invention, there is provided a plasma processing apparatus in addition to any one of the first to third aspects.
The electric field intensity applied between the electrodes 2 and 3 is 1 to 200 kV /
cm.

According to a fifth aspect of the present invention, there is provided a plasma processing apparatus according to any one of the first to fourth aspects.
The present invention is characterized in that a pulse-like high voltage is superimposed on a voltage having an alternating voltage waveform with no pause applied between the electrodes 2 and 3.

According to a sixth aspect of the present invention, in addition to the configuration of the fifth aspect, the pulsed high voltage is superimposed after a lapse of a predetermined time immediately after the voltage polarity of the alternating voltage waveform changes. It is characterized by doing.

According to a seventh aspect of the present invention, there is provided the plasma processing apparatus according to the fifth or sixth aspect, wherein a plurality of pulsed high voltages are superimposed in one cycle of the alternating voltage waveform. Is what you do.

[0014] Further, a plasma processing apparatus according to claim 8 of the present invention, in addition to the configuration of any of claims 5 to 7,
It is characterized in that the rise time of the pulse-like high voltage is set to 0.1 μsec or less.

According to a ninth aspect of the present invention, there is provided a plasma processing apparatus according to the fifth aspect,
The peak value of the pulse-like high voltage is set to be equal to or more than the maximum voltage value of the alternating voltage waveform.

According to a tenth aspect of the present invention, there is provided a plasma processing apparatus according to the first aspect, wherein a plurality of alternating voltage waveforms applied between the electrodes 2 and 3 without a pause are provided. It is characterized by being formed by superposing alternating voltage waveforms of various frequencies.

A plasma processing method according to an eleventh aspect of the present invention is characterized in that the plasma processing is performed using the plasma processing apparatus according to any one of the first to tenth aspects.

[0018]

Embodiments of the present invention will be described below.

First, basic characteristics of the dielectric barrier discharge will be described below (reference: Izumi Hayashi, "High Voltage Plasma Engineering", p. 35, Maruzen Co., Ltd.). In the dielectric barrier discharge, a pair of (a pair of) electrodes 2 and 3 are arranged to face each other to form a discharge space 34 between the electrodes 2 and 3, and as shown in FIG. A dielectric (solid dielectric) 32 is provided on the surface of the discharge space 34 on the side of the discharge space 34 to cover the surface of the electrodes 2 and 3 on the side of the discharge space 34, or as shown in FIG. 3 may be provided on the surface of the discharge space 34 on the side of the discharge space 34 so as to cover the surface of the electrode 2 on the side of the discharge space 34, so that direct discharge between the electrodes 2 and 3 can be achieved. In a state where no
This is a discharge phenomenon that occurs in the discharge space 34 when an alternating voltage is applied between the electrodes 2 and 3 by the power supply 43 in this state. When the discharge space 34 is filled with a gas of about 1 atm and an alternating high voltage is applied between the electrodes 2 and 3 in this way, as shown in FIG. Streaks occur uniformly. The streaks of light are due to the streamer 11. The electric charge of the streamer 11 cannot flow into the electrodes 2 and 3 because the electrodes 2 and 3 are covered with the dielectric 32, and thus the electric charge in the discharge space 34 is transferred to the dielectric 32 on the surface of the electrodes 2 and 3. It is accumulated (this is called wall charge).

When the polarity of the power supply 43 is reversed from the state shown in FIG. 16A to the state shown in FIG. 16B, the electric field due to the wall charges is in the opposite direction to the alternating electric field supplied from the power supply 43. When the charge increases, the electric field in the discharge space 34 decreases, and the dielectric barrier discharge stops. However, the next power supply 4
In the half cycle of the alternating voltage of No. 3, since the direction of the electric field by the wall charges and the direction of the alternating electric field supplied from the power supply 43 match, the dielectric barrier discharge easily occurs. That is, once the dielectric barrier discharge starts, the dielectric barrier discharge can be maintained at a relatively low voltage thereafter.

Since the innumerable streamers 11 generated in the dielectric barrier discharge are the dielectric barrier discharges themselves generated in the discharge space 34, the number of streamers 11 generated and the current value flowing in each streamer 11 are determined by the plasma. Affects density. FIG. 13 shows an example of the current-voltage characteristic in the dielectric barrier discharge. As is apparent from the current-voltage characteristics, the current waveform (gap current waveform) in the dielectric barrier discharge has a spike-like current superimposed on a sinusoidal current waveform. The current is a current flowing in the discharge space 34 when the streamer 11 is generated. FIG. 13 shows the waveform of the applied voltage and the waveform of the gap current, respectively.

FIG. 14 shows an equivalent circuit of the dielectric barrier discharge. Each symbol in the figure is as follows. Cd: capacitance of the dielectric 32 on the surfaces of the electrodes 2 and 3 Cg: equivalent capacitance of the discharge space 34 (discharge gap) Rp: plasma impedance The countless streamers 11 generated in the discharge space 34 are shown in FIG. Turning the switch S on and off corresponds to a current flowing through Rp. As described above, the plasma density is determined by the number of streamers 11 generated and each streamer 11.
The frequency of the ON / OFF of the switch S, the ON time, and O
It is defined by the current value during N hours.

The operation of the dielectric barrier discharge will be described briefly using this equivalent circuit. FIG. 15 is a schematic diagram of a voltage waveform applied by the power supply 43 and current waveforms of Cg and Rp. C
Since the current flowing through g is the charge / discharge current of the equivalent capacitor in the discharge space 34, it does not become the current that determines the plasma density. On the other hand, when the switch S is turned on, R
Since the current flowing through p is the current of the streamer 11 itself, the plasma density increases as the duration of the current and the current value increase.

As described above, the dielectric barrier discharge stops when the wall charges increase and the electric field in the discharge space 34 decreases.
Therefore, a region where the voltage applied to the electrodes 2 and 3 decreases beyond the maximum value (region A1 in FIG. 15) or a region where the voltage applied to the electrodes 2 and 3 increases beyond the minimum value (A in FIG. 15)
2), no dielectric barrier discharge occurs and the power supply 43
Until the polarity of the alternating voltage applied reverses, only the charge / discharge current of the capacitor flows. Therefore, the time of the region A2 in which the voltage applied to the electrodes 2 and 3 increases beyond the minimum value (this is referred to as a rise time) or the time of the region A1 in which the voltage applied to the electrodes 2 and 3 decreases beyond the maximum value By shortening the fall time, the time during which the dielectric barrier discharge stops can be shortened and the plasma density can be increased, and the plasma processing capability (efficiency) can be increased. is there.

FIG. 1 shows an example of an embodiment of the present invention.
In this plasma processing apparatus, a power supply 43 for forming a discharge space 34 between electrodes 2 and 3 disposed opposite to each other and applying a voltage having an alternating voltage waveform with no pause between electrodes 2 and 3 is provided.
Is connected to the electrodes 2 and 3 and both electrodes 2 and 3
Is provided on the discharge space 34 side of the discharge space 34, and the nozzle 12 for supplying the plasma generation gas to the discharge space 34.
Are disposed on the sides of the electrodes 2 and 3.

The electrodes 2 and 3 are formed in a plate shape from a metal material such as copper, aluminum, brass and stainless steel having high corrosion resistance. The dielectric 32 is made of a dielectric material (insulating material).
And a dielectric material having a dielectric constant of 2000 or less, such as enamel, quartz, alumina, and yttria partially stabilized zirconium. Ceramic material,
Alumina (Al ₂ O ₃ ), titanium oxide (TiO _{2 with} titania
₂ ), SiO ₂ , AlN, Si ₃ N, SiC, DLC (diamond-like carbon film), barium titanate, PZT
(Lead zirconate titanate), magnesia (MgO) alone or a material containing magnesia can be exemplified.

In providing such a dielectric 32 on the surfaces of the electrodes 2 and 3 for coating (coating),
A method in which a plate-shaped dielectric 32 is adhered to and adhered to the surfaces of the electrodes 2 and 3;
A plasma spraying method in which powders such as titanium oxide and PZT are dispersed in plasma and sprayed onto the surfaces of the electrodes 2 and 3, and inorganic powders such as silica, tin oxide, titania, zirconia, and alumina are dispersed with a solvent or the like. A so-called enamel coating method in which the surfaces of the electrodes 2 and 3 are coated by spraying with a spray or the like and then melted at a temperature of 600 ° C. or more, a method of forming a glassy film by a sol-gel method, and the like can be adopted. Further, a vapor deposition method (C
VD) or physical vapor deposition (PVD)
Can also be coated.

When the dielectric 32 is formed of an enamel, a conventional enamel forming method can be used as it is. For example, a glass handbook (Asakura Shoten, 19
91.4.10, 12th printing, pp. 191 to 196) and a list of practical surface modification technologies (edited by the Technical Materials Research Association, 1993.
The method described in 3.25 First Edition, p. 731) can be employed. Specifically, a glaze made of an inorganic powder (glassy material) such as silica, tin oxide, titania, zirconia, and alumina is supplied to the surfaces of the electrodes 2 and 3 by spraying or dipping. To form a glaze film on the surfaces of the electrodes 2 and 3, and then heat-treat at a temperature of 480 to 1000 ° C. for 1 to 15 minutes to fuse the inorganic powder on the surfaces of the electrodes 2 and 3. be able to.

The thickness of the dielectric 32 is preferably 0.1 to 2 mm. If the thickness of the dielectric 32 is less than 0.1 mm, dielectric breakdown of the dielectric 32 may occur and dielectric barrier discharge may not occur. If the thickness of the dielectric 32 exceeds 2 mm, the discharge starting voltage may decrease. It may become high and it may take a long time to start the operation of the apparatus.

By providing the dielectric 32 on the surfaces of the electrodes 2 and 3 as described above, the dielectric barrier discharge as described above can be generated and a large number of streamers 11 can be formed.
The electrodes 2 and 3 can be protected from the plasma sputtering action of plasma and the corrosive action of the plasma generating gas, and the deterioration of the electrodes 2 and 3 can be reduced. Is not generated, and the object to be processed is prevented from being contaminated by impurities even when used for a long period of time.

As the plasma generating gas, air, preferably dry air containing almost no water can be used. In the present invention, since a dielectric barrier discharge, which is not a glow discharge, is used, there is no need to use a special gas such as a rare gas, and the cost for plasma processing can be reduced. Further, He gas is used as a plasma generation gas for the purpose of stably generating a dielectric barrier discharge.
A rare gas other than He or a mixed gas of a rare gas other than He and a reaction gas can be used. As the rare gas, argon, neon, krypton, or the like can be used, but it is preferable to use argon in consideration of discharge stability and economy. As described above, in the present invention, since the dielectric barrier discharge which is not the glow discharge is used, it is not necessary to use helium as a rare gas, and the cost for the plasma processing can be reduced. The type of the reaction gas can be arbitrarily selected depending on the content of the treatment. For example, cleaning of organic substances present on the surface of the object to be processed, stripping of resist, etching of organic film, LC
When the surface cleaning of D or the surface cleaning of the glass plate is performed, it is preferable to use an oxidizing gas such as oxygen, air, CO ₂ , or N ₂ O. In addition, C is used as a reaction gas.
Fluorine-based gas such as F ₄ can also be used as appropriate, it is effective to use a fluorine-based gas in the case of performing the etching of the silicon. In the case of reducing a metal oxide, a reducing gas such as hydrogen or ammonia can be used. The amount of the reaction gas added is 10% by volume or less, preferably 0.1 to 5% by volume, based on the total amount of the rare gas. If the addition amount of the reaction gas is less than 0.1% by volume, the treatment effect may be reduced. If the addition amount of the reaction gas exceeds 10% by volume, the dielectric barrier discharge may become unstable. .

The plasma processing of the piece-like (short) plate-like workpiece 4 such as a circuit board or a glass substrate for a liquid crystal using the plasma processing apparatus thus formed is performed as follows. Do it. First, a gas for plasma generation is blown out from the nozzle 12 and introduced into the discharge space 34, and a voltage having an alternating voltage waveform having no pause time is applied between the electrodes 2 and 3 by the power supply 43, so that the gas at or near atmospheric pressure is applied. Under pressure (93.3-106.7 kPa
(700 to 800 Torr)), a dielectric barrier discharge is generated in the discharge space 34, and the plasma for generating the plasma is converted into plasma by the dielectric barrier discharge, and the plasma composed of a large number of streamers 11 containing plasma active species is discharged into the discharge space 3.
4 is generated. Thereafter, as shown by an arrow in FIG. 1, the workpiece 4 is introduced into the discharge space 34 and plasma is supplied to the surface of the workpiece 4 to perform plasma processing.

As a voltage having an alternating voltage waveform without a pause time, for example, a voltage having a sine wave waveform can be used. Alternatively, a voltage having an alternating voltage waveform having no pause time as shown in FIGS. 17A, 17B, and 17C can be used.
In the present invention, at least one, and preferably both, of the rising time and the falling time of the alternating voltage waveform are set to 100 μsec or less. If both the rise time and the fall time are 100 μsec or more, the plasma density in the discharge space 34 cannot be increased, and the plasma processing ability decreases, and the streamer 11 is uniformly generated in the discharge space 34. This makes it difficult to perform uniform plasma processing. The shorter the rise time and the fall time are, the more preferable. Therefore, the lower limit is not particularly set. However, the currently available power supply 43 capable of shortening the rise time and the fall time is 40 nsec, which is substantially It is the lower limit.
However, if a rise time and a fall time shorter than 40 nsec can be realized by future technical development, it is preferable that the time be shorter than 40 nsec.

In the present invention, as shown in FIG. 18 (a), a pulse-like high voltage is superimposed on a voltage of an alternating voltage waveform having no pause time applied between the electrodes 2 and 3.
It may be applied between three. By superimposing the pulse-like high voltage on the voltage having the alternating voltage waveform in this manner, electrons can be accelerated in the discharge space 34 to generate high-energy electrons. It is possible to efficiently ionize and excite the plasma generation gas in the inside, to generate high-density plasma, and to increase the efficiency of plasma processing.

When the pulse-like high voltage is superimposed on the voltage of the alternating voltage waveform in this manner, the pulse-like high voltage is superimposed after a predetermined time has elapsed from immediately after the voltage polarity of the alternating voltage waveform has changed, and the pulse to be superposed is superposed. It is preferable to change the time during which the high voltage is applied, thereby changing the state of acceleration of electrons in the discharge space 34. Therefore, by changing the timing of applying a pulsed high voltage between the electrodes 2 and 3, it is possible to control the ionization and excitation state of the plasma generating gas in the discharge space 34, and to perform the desired plasma processing. It is possible to easily create a plasma state suitable for the above.

Further, as shown in FIG. 18B, a plurality of pulsed high voltages may be superimposed in one cycle of the alternating voltage waveform, whereby the discharge space is higher than in the case of FIG. 18A. This makes it easier to change the acceleration state of the electrons in the electron beam. Therefore, by changing the timing of applying a pulsed high voltage between the electrodes 2 and 3, the ionization and excitation state of the plasma generating gas in the discharge space 34 can be more easily controlled, and the desired plasma processing can be performed. It is possible to more easily create a plasma state suitable for the above.

The rise time of the pulsed high voltage is preferably set to 0.1 μsec or less. If the rise time of the pulsed high voltage exceeds 0.1 μsec,
The ions in the discharge space 34 can also move following the pulsed voltage, and there is a possibility that only the electrons cannot be efficiently accelerated. Therefore, by setting the rise time of the pulsed high voltage to 0.1 μsec or less, the gas for plasma generation can be efficiently ionized and excited in the discharge space 34, and high-density plasma can be generated. Thus, the efficiency of the plasma processing can be increased.

It is preferable that the peak value of the pulse-like high voltage is not less than the maximum voltage value of the alternating voltage waveform. When the peak value of the pulsed high voltage is less than the maximum voltage value of the alternating voltage waveform, the effect of superimposing the pulsed high voltage is reduced, and the plasma state is almost the same as when no pulsed voltage is superimposed. Accordingly, by setting the peak value of the pulsed high voltage to be equal to or higher than the maximum voltage value of the alternating voltage waveform, the plasma generating gas can be efficiently ionized and excited in the discharge space 34, and the high density plasma can be generated. And the efficiency of the plasma processing can be increased.

The alternating voltage waveform having no pause time applied between the electrodes 2 and 3 of the present invention is preferably formed by superimposing alternating voltage waveforms of a plurality of kinds of frequencies and having a waveform as shown in FIG. Preferably, this allows the electrons in the discharge space 34 to be accelerated by the voltage of the frequency of the high-frequency component to generate high-energy electrons, and the high-energy electrons cause the plasma generation gas to be generated in the discharge space 34. It can efficiently ionize and excite, generate high-density plasma, and increase the efficiency of plasma processing.

The repetition frequency of the alternating voltage waveform having no pause applied between the electrodes 2 and 3 is 0.5.
Preferably, it is set to 200 kHz. If the repetition frequency is less than 0.5 kHz, the number of streamers 11 generated per unit time decreases, so that the plasma density of the dielectric barrier discharge decreases and the performance (efficiency) of the plasma processing decreases. On the other hand, if the repetition frequency is higher than 200 kHz, the number of streamers 11 generated in a unit time increases, so that the plasma density increases, but the arc is easily generated and the discharge shrinks (shrinks). ) Occurs and the discharge space 34
There is a possibility that the dielectric barrier discharge in the entire region becomes difficult.

Further, when the dielectric barrier discharge occurs, the electrodes 2, 3
The strength of the electric field applied between the electrodes varies depending on the distance between the electrodes 2 and 3 (gap length), the type of plasma generating gas, the type of plasma processing target (object to be processed), and the like. It is preferably set to cm. This electric field strength is (applied voltage between electrodes 2 and 3) / (electrode 2,
3 interval), and this value is 1 kV
If it is less than / cm, the plasma density of the dielectric barrier discharge becomes low, and the performance (efficiency) of the plasma processing may be reduced.
If it is larger than cm, an arc is likely to be generated and the workpiece 4 may be damaged.

In the plasma processing apparatus of the present invention,
Since plasma composed of a large number of streamers 11 is generated by the dielectric barrier discharge, and this plasma is supplied to the surface of the processing object 4 to perform the plasma processing, He used for generating the glow discharge becomes unnecessary. It is possible,
The cost required for the plasma processing can be kept low. Further, since the dielectric barrier discharge is used instead of the glow discharge, the power supplied to the discharge space 34 can be increased, the plasma density can be increased, and the plasma processing ability can be enhanced. Things. That is, in the glow discharge, a current flows in the form of a current pulse only once in a half cycle of a voltage, whereas in the dielectric barrier discharge, a large number of current pulses are generated in a form corresponding to the streamer 11. Therefore, the input power can be increased in the dielectric barrier discharge. In the conventional plasma processing using glow discharge, the power applied to the discharge space 34 is limited to about 2 W / cm ² , but in the present invention, the power applied to the discharge space 34 is about 5 W / cm ^2. It can supply electric power. Further, in the present invention, at least one of the rise time and the fall time of the alternating voltage waveform is set to 100 μsec or less.
The plasma density in the discharge space 34 can be increased, and the performance of plasma processing can be increased. In addition, the streamer 11 is easily generated uniformly in the discharge space 34, and the plasma density in the discharge space 34 is increased. Is high, and uniform plasma processing can be performed.

FIG. 2 shows another embodiment. This plasma processing apparatus performs plasma processing in an in-line system. The chamber 1 formed in a box shape has O
A packing such as a ring is provided to form a high airtightness. A roller 5 is provided inside the chamber 1 as a means for transporting the electrodes 2, 3 and the workpiece 4. One side surface of the chamber 1 is formed as an inlet 7, and the inlet 7 is formed to be openable and closable by an inline-type inlet door 21 provided in the chamber 1.
That is, the entrance door 21 is driven up and down by air pressure or the like, and the entrance 7 is opened by being driven up,
When driven downward, the inlet 7 is closed.
The other side surface of the chamber 1 is formed as an outlet 8 facing the inlet 7, and the outlet 8 is formed to be openable and closable by an in-line type outlet door 22 provided in the chamber 1. That is, the outlet door 22 is driven up and down by air pressure or the like, and the outlet 8 is opened by being driven up, and the outlet 8 is closed by being driven down. Further, a gas supply pipe 30 is projected from the upper surface of the chamber 1 and a gas discharge pipe 31 is projected from the lower surface of the chamber 1.

The chamber 1 can be made of synthetic resin such as acrylic resin or metal such as stainless steel.
Preferably, the inner surface of the chamber 1 is coated with the same insulator as the dielectric 32. By coating the inner surface of the chamber 1 with an insulator in this way, it is possible to prevent discharge from occurring between the electrodes 2 and 3 and the inner surface of the chamber 1, and to improve the discharge efficiency between the electrodes 2 and 3. It is possible to efficiently generate plasma. The outer surface of the chamber 1 may be coated with an insulating material.

As shown in FIG. 3, the electrodes 2 and 3 are formed of the same metal material as described above in a cylindrical shape.
Has a substantially rectangular cross section, and the electrode 3 has a substantially circular cross section. Further, the inside of the electrodes 2 and 3 is formed as a flow path 33 through which a refrigerant can pass. As the refrigerant, ion-exchanged water or pure water can be used. By using ion-exchanged water or pure water, no impurities are contained in the refrigerant, and the electrodes 2 and 3 are hardly corroded by the refrigerant. In addition, it has antifreeze at 0 ° C. as a refrigerant,
In addition, it is preferable that the liquid has electrical insulating properties, nonflammability, and chemical stability.
The withstand voltage at m intervals is preferably 10 kV or more. The reason for using a refrigerant having an insulating property in this range is to prevent electric leakage from an electrode to which a high voltage is applied. Examples of the refrigerant having such properties include perfluorocarbon, hydrofluoroether and the like, and may be a mixed liquid obtained by adding 5 to 60% by weight of ethylene glycol to pure water. Further, the refrigerant may be air.

The electrodes 2 and 3 are cooled by passing a coolant through the flow path 33 during the dielectric barrier discharge, whereby the alternating voltage having a high frequency under the atmospheric pressure or a pressure in the vicinity thereof is obtained. Even if a dielectric barrier discharge is generated by using a waveform voltage, the temperature rise of the electrodes 2 and 3 can be suppressed, and the temperature of the plasma (gas temperature) does not increase so that the thermal damage to the object 4 is prevented. Can be reduced. Further, local heating of the discharge space 34 can be prevented, and the streamer 11 can be generated more uniformly over the entire area of the discharge space 34.

The electrodes 2 and 3 formed as described above are entirely covered with a dielectric 32 similar to the above.
The electrodes 2 and 3 are arranged in a plurality in the chamber 1 by fixing their ends to holders provided on the inner surface of the chamber 1. There are three electrodes 2, which are arranged so as to be arranged in the direction opposite to the inlet 7 and the outlet 8.
Each electrode 2 is arranged so that its longitudinal direction is substantially horizontal. There are six electrodes 3, which are arranged below the electrodes 2 so as to be arranged in the direction opposite to the inlet 7 and the outlet 8, and each electrode 3 is arranged so that its longitudinal direction is substantially horizontal. Each of the electrodes 2 and 3 is arranged at a predetermined interval so that the two electrodes 3 face up and down with respect to one electrode 2, and the space between the facing electrodes 2 and 3 ( The opposing space is formed as a discharge space 34. As shown in FIG. 4, the electrodes 2 and 3 are electrically connected to a power supply 43, and the electrode 3 is grounded.

The roller 5 is formed in a circular cross section using a synthetic resin having high heat resistance such as polytetrafluoroethylene (trade name: Teflon). There are four rollers 5 in the chamber 1, and two rollers 3 are interposed between the adjacent rollers 5 and 5, and are arranged so as to be arranged in a direction opposite to the entrance 7 and the exit 8. Each roller 5 is arranged such that its longitudinal direction is substantially horizontal. Further, the upper part of the roller 5 is located above the upper part of the electrode 3. That is, the roller 5 is disposed in the chamber 1 and at a location other than the opposing space between the electrodes 2 and 3 (discharge space 34). One end of each roller 5 penetrates the side wall of the chamber 1 and protrudes to the outside of the chamber 1. A drive transmission belt 36 is hung over the end of the roller 5 using a pulley or the like. I have. As shown in FIG. 5, the drive transmission belt 36 is hung on a rotation shaft 37 of a drive source 10 such as a motor disposed outside the chamber 1. By providing the driving source 10 of the roller 5 outside the chamber 1 in this manner,
The size of the chamber 1 can be reduced. Then, by driving the drive source 10 to rotate the rotation shaft 37, the drive transmission belt 36 advances, and the roller 5 is rotationally driven by the advance of the drive transmission belt 36.

The plasma processing of the piece-like (short) plate-like workpiece 4 such as a circuit substrate or a liquid crystal glass substrate using the plasma processing apparatus thus formed is performed as follows. Do it. First, as shown by the arrow a, the same plasma generating gas as described above is supplied into the chamber 1 through the gas supply pipe 30 and the voltage of the alternating voltage waveform without pause time is applied to the electrodes 2 by the power supply 43 as described above. By applying the voltage between the three, a dielectric barrier discharge is generated in the discharge space 34 under the atmospheric pressure or a pressure close to the atmospheric pressure. Is generated in the discharge space 34. The surplus plasma generating gas is discharged out of the chamber 1 through the gas discharge pipe 31 as shown by an arrow b.

After the plasma is generated in the discharge space 34 as described above, the roller 5 is driven to rotate clockwise by operating the drive source 10, and FIG.
As shown in (2), the entrance door 21 is moved upward to open the entrance 7 of the chamber 1, and the workpiece 4 is introduced into the chamber 1 from the entrance 7. The workpiece 4 introduced into the chamber 1 is placed on the roller 5, and is conveyed to the discharge space 34 by the rotation of the roller 5. Also, the object to be treated 4
6 is set in the chamber 1, the entrance door 21 is driven downward to drive the entrance 7 of the chamber 1 as shown in FIG.
And the inside of the chamber 1 is sealed. And FIG.
As shown in (c), the workpiece 4 introduced into the chamber 1 passes through the discharge space 34 while being transported by the rollers 5 and is continuously subjected to plasma processing. Thereafter, when the object 4 approaches the outlet 8, as shown in FIG. 6 (d), the outlet door 22 is driven upward to open the outlet 8 of the chamber 1, and as shown in FIG. 6 (e). Then, the workpiece 4 subjected to the plasma processing is led out from the outlet 8 of the chamber 1 by rotating the roller 5. In this manner, a plurality of workpieces 4
Can be subjected to the plasma processing while being continuously transported.

The following processing method can also be employed. After the plasma is generated in the discharge space 34 as described above, the roller 5 is driven to rotate clockwise by operating the drive source 10 and the entrance door 21 is moved upward as shown in FIG. Drive to chamber 1
Is opened, and the workpiece 4 is introduced into the chamber 1 from the inlet 7. The workpiece 4 introduced into the chamber 1 is placed on the roller 5, and is conveyed to a substantially central portion in the discharge space 34 by rotating the roller 5. Also,
When the object 4 is conveyed to a substantially central portion in the discharge space 34, the drive source 10 is stopped to stop the rotation of the roller 5, and the conveyance of the object 4 is interrupted. next,
As shown in FIG. 6B, the entrance door 21 is moved downward to close the entrance 7 of the chamber 1 and hermetically close the inside of the chamber 1. Next, as shown in FIG. 6C, the processing target 4 is stopped in the discharge space 34 for a predetermined time, and the processing target 4 is subjected to plasma processing. Next, as shown in FIG. 6D, the outlet door 22 is moved upward to open the outlet 8 of the chamber 1. Next, by driving the drive source 10 to rotate the roller 5 clockwise, the conveyance of the workpiece 4 is resumed, and the plasma processing is performed from the outlet 8 of the chamber 1 as shown in FIG. The processed object 4 is derived. By supplying the workpiece 4 to the plasma processing apparatus in this manner, a plurality of workpieces 4 can be continuously subjected to plasma processing.

In this embodiment, since the rollers 5 are provided only in the chamber 1 as the transporting means for transporting the workpiece 4, the transporting means can be prevented from protruding greatly outside the chamber 1 and can be reduced in size. It can be made. Further, since a plurality of rollers 5 are provided side by side over substantially the entire length of the chamber 1 in the direction opposite to the inlet 7 and the outlet 8, the workpiece 4 is supported from below by the plurality of rollers 5 over substantially the entire length. Thus, the processing object 4 can be prevented from being bent in the chamber 1, so that the processing of the processing object 4 and the plasma processing of the processing object 4 can be performed satisfactorily. In addition, by arranging a plurality of electrodes 2 side by side and arranging a plurality of electrodes 3 below each electrode 2 so as to face each other, and by arranging the roller 5 between adjacent electrodes 3, the roller 5 Can be arranged in the chamber 1 and at a place other than the opposing space (discharge space 34) between the electrodes 2 and 3, and the roller 2 is prevented from being interposed between the electrode 2 and the electrode 3.
3 can prevent an obstacle of the dielectric barrier discharge from being present. The dielectric barrier discharge occurs stably, and a large number of streamers 11 are generated almost uniformly over the entire discharge space 34. That can be done. In addition, the plasma processing can be performed on the thick workpiece 4 having a thickness substantially equal to the distance between the electrodes 2 and 3. In addition, the inlet 7 and the outlet 8 are opened only when the workpiece 4 is introduced into the chamber 1 and when the workpiece 4 is led out of the chamber 1, and the inlet 7 and the outlet 8 are closed during the plasma processing. By setting the state, useless outflow of the plasma generation gas from the chamber 1 can be minimized, and the plasma generation gas can be used efficiently.

FIG. 7 shows another embodiment. This plasma processing apparatus performs plasma processing by a shuttle system, and has a box-shaped chamber 1 similar to the above.
Is formed as an entrance / exit 6, and the entrance / exit 6 is formed to be openable and closable by a shuttle-type entrance door 20 provided in the chamber 1. That is,
The entrance door 20 is driven up and down by air pressure or the like. The entrance door 6 is opened by being driven upward, and the entrance 6 is closed by being driven downward. Further, inside the chamber 1, the same electrodes 2, 3,
A roller 5 is provided, and a driving source 10 is provided outside the chamber 1 in the same manner as described above.

The plasma processing of the piece-like (short) plate-like workpiece 4 such as a circuit board or a liquid crystal glass board using the plasma processing apparatus thus formed is performed as follows. Do it. First, a plasma is generated by generating a dielectric barrier discharge in the discharge space 34 in the same manner as described above. Next, the roller 5 is driven to rotate clockwise by operating the drive source 10, and FIG.
As shown in (a), the entrance door 20 is moved upward to open the entrance 6 of the chamber 1, and the workpiece 4 is introduced into the chamber 1 from the entrance 6. The workpiece 4 introduced into the chamber 1 is placed on the roller 5, and is conveyed to the discharge space 34 by the rotation of the roller 5. Also,
When the workpiece 4 is accommodated in the chamber 1, as shown in FIG. 8B, the entrance door 20 is driven downward to close the entrance 6 of the chamber 1 and hermetically seal the inside of the chamber 1. Then, as shown in FIG. 8C, the workpiece 4 introduced into the chamber 1 is continuously plasma-treated while being transported by the rollers 5 toward the side opposite to the entrance 6. Thereafter, when the workpiece 4 approaches the side opposite to the entrance 6, the roller 5 is driven to rotate counterclockwise, thereby transporting the workpiece 4 toward the entrance 6. At this time (when the workpiece 4 is being conveyed toward the entrance 6), the workpiece 4 may or may not be subjected to the plasma processing. Thereafter, when the workpiece 4 approaches the entrance 6, as shown in FIG. 8D, the entrance door 20 is moved upward to open the entrance 6 of the chamber 1, and the plasma-treated workpiece 4 is opened. Is derived by rotating the roller 5. In this way, the plasma processing can be continuously performed while the workpiece 4 is being conveyed.

Further, the following processing method can be adopted. After the plasma is generated in the discharge space 34 as described above, the roller 5 is driven to rotate clockwise by operating the driving source 10 and the entrance door 20 is moved upward as shown in FIG. The chamber 6 is driven to open the entrance 6 of the chamber 1, and the workpiece 4 is introduced into the chamber 1 from the entrance 6. The workpiece 4 introduced into the chamber 1 is placed on the roller 5, and is conveyed to a substantially central portion in the discharge space 34 by rotating the roller 5.
When the processing object 4 is transported to a substantially central portion in the discharge space 34, the driving source 10 is stopped to stop the rotation of the roller 5, and the transport of the processing object 4 is interrupted. Next, as shown in FIG. 8B, the entrance door 20 is moved downward to close the entrance 6 of the chamber 1 and the chamber 1 is closed.
Seal the inside. Next, as shown in FIG. 8C, the processing target 4 is stopped in the discharge space 34 for a predetermined time, and the processing target 4 is subjected to plasma processing. Next, as shown in FIG. 8D, the entrance door 20 is moved upward to open the entrance 6 of the chamber 1. Next, by driving the drive source 10 to rotate the roller 5 in a counterclockwise direction, the conveyance of the workpiece 4 is restarted, and the plasma-processed workpiece 4 is led out from the entrance 6 of the chamber 1. . By supplying the workpiece 4 to the plasma processing apparatus in this manner, a plurality of workpieces 4 can be continuously subjected to plasma processing.

This embodiment has the same effects as those of the above-described embodiment. In addition, when the object 4 is introduced into the chamber 1 and when the object 4 is
By opening the entrance 6 only at the time of derivation of the gas and by closing the entrance 6 at the time of plasma processing, useless outflow of the plasma generation gas from the chamber 1 can be minimized. Can be used efficiently. An entrance 6 for introducing the object 4 into the chamber 1 and leading out the object 4 from the chamber 1 is provided on one side of the chamber 1.
Is provided, and the roller 5 for transporting the workpiece 4 is formed so as to be rotatable in both normal rotation and reverse rotation, so that the workpiece 4 is introduced into the chamber 1 from the entrance 6 by the forward rotation of the roller 5. At the same time, the processing object 4 is led out of the chamber 1 from the entrance 6 by reversing the roller 5, so that the processing object 4 is introduced into the chamber 1 from only the side having the entrance 6 and the processing object 4 from the chamber 1. The space required around the chamber 1 during plasma processing can be reduced to save space.

FIG. 9 shows another embodiment. The chamber 1 of the plasma processing apparatus is formed in a box shape in the same manner as described above, and a slit 50 having a substantially horizontal slit is formed on one side wall 50 of the chamber 1. On the other side wall 51, a slit-like outlet 8 that is long in a substantially horizontal direction is formed so as to face the inlet 7. Further, the same electrodes 2, 3 and rollers 5 as described above are provided inside the chamber 1, and a drive source 10 is provided outside the chamber 1 in the same manner as described above. Further, an introduction-side relaxation chamber 9 a is integrally formed as a relaxation chamber 9 outside one side wall 50 of the chamber 1. The introduction-side relaxation chamber 9 a is formed so as to surround the inlet 7, and the side wall 52 of the introduction-side relaxation chamber 9 a facing the one side wall 50 of the chamber 1 has a substantially horizontally long slit-like relaxation. The chamber inlet 40 is formed to face the inlet 7. In addition, a roller 5 rotatably formed like the roller 5 in the chamber 1 is provided in the introduction-side relaxation chamber 9a. Furthermore, chamber 1
On the outside of the other side wall 51, an outlet-side relaxation chamber 9b is integrally formed as a relaxation chamber 9. The outlet side relaxation chamber 9 b is formed so as to surround the outlet 8, and the side wall 53 of the outlet side relaxation chamber 9 b facing the other side wall 51 of the chamber 1 has a substantially horizontal slit-like relaxation. The chamber outlet 41 is formed to face the outlet 8. In addition, a roller 5 rotatably formed like the roller 5 in the chamber 1 is provided in the introduction-side relaxation chamber 9b.

The plasma processing of the piece-like (short) plate-like workpiece 4 such as a circuit substrate or a liquid crystal glass substrate using the plasma processing apparatus thus formed is performed as follows. Do it. First, a plasma is generated by generating a dielectric barrier discharge in the discharge space 34 in the same manner as described above. Next, the roller 5 is driven to rotate clockwise by operating the drive source 10, and at the same time, as shown in FIG.
As shown in FIG. 1A, the workpiece 4 is introduced into the chamber 1 from the relaxation chamber introduction port 40 and the entrance 7. Chamber 1
The object 4 introduced into the inside is placed on the roller 5 and is conveyed to the discharge space 34 by the rotation of the roller 5. Then, as shown in FIG. 10B, the workpiece 4 introduced into the chamber 1 passes through the discharge space 34 while being transported by the rollers 5 and is continuously subjected to plasma processing. Thereafter, as shown in FIG. 10C, the workpiece 4 subjected to the plasma processing is led out from the outlet 8 and the relaxation chamber outlet 41 by rotating the roller 5. By supplying the workpiece 4 to the plasma processing apparatus in this manner, a plurality of workpieces 4 can be continuously subjected to plasma processing.

Further, the following processing method can be adopted. After the plasma is generated in the discharge space 34 as described above, the roller 5 is driven to rotate clockwise by operating the drive source 10, and FIG.
As shown in (1), the object 4 is introduced into the chamber 1 from the relaxation chamber introduction port 40 and the entrance 7. The workpiece 4 introduced into the chamber 1 is placed on the roller 5, and is conveyed to a substantially central portion in the discharge space 34 by rotating the roller 5. When the processing object 4 is conveyed to a substantially central portion in the discharge space 34, as shown in FIG.
0, the rotation of the roller 5 is stopped, the conveyance of the object 4 is interrupted, the object 4 is stopped in the discharge space 34 for a predetermined time, and the object 4 is subjected to plasma processing. . Next, by driving the drive source 10 to rotate the roller 5 clockwise, the conveyance of the workpiece 4 is resumed, and as shown in FIG.
The plasma-processed object 4 is led out from the outlet 8 and the relaxation chamber outlet 41. By supplying the workpiece 4 to the plasma processing apparatus in this manner, a plurality of workpieces 4 can be continuously subjected to plasma processing.

In this embodiment, since the entrance 7 and the exit 8 are formed in a slit shape which is always open, a door for opening and closing the entrance 7 and the exit 8 and a mechanism for opening / closing the door are not required. It can be simplified.
Further, since the relaxation chamber 9 is provided so as to surround the inlet 7 and the outlet 8, the amount of the plasma generating gas flowing out of the chamber 1 through the inlet 7 and the outlet 8 can be reduced, and the chamber 1 can be reduced through the inlet 7 and the outlet 8. The amount of outside air (air) flowing into the chamber can be reduced, and
, The concentration of the plasma generating gas in the chamber 1 can be kept substantially constant even when the inlet 7 and the outlet 8 are always open, and the uniformity can be maintained. Plasma can be generated stably, and unnecessary outflow of the plasma generation gas from the chamber 1 can be minimized, so that the plasma generation gas can be used efficiently.

In any of the above embodiments, the number of the electrodes 2, 3 and the rollers 5, and the positions of the gas supply pipe 30 and the gas discharge pipe 31 are arbitrary.

[0062]

The present invention will be described below in detail with reference to examples.

(Example 1) The plasma processing of the workpiece 4 was performed using the plasma processing apparatus shown in FIG.

The electrodes 2 and 3 are made of stainless steel (SUS30).
A discharge space 34 was formed by arranging the electrodes 2 and 3 to face each other at an interval of 5 mm. The surface of the electrodes 2 and 3 on the side of the discharge space 34 has a thickness of 1 mm.
Formed a dielectric 32 made of quartz glass. Dry air was used as the plasma generation gas. The glass 4 for liquid crystal (the contact angle of water before the plasma treatment is about 45
°)).

Then, a gas for plasma generation is blown out from the nozzle 12 to be introduced into the discharge space 34 and the power source 43.
, The voltage of the alternating voltage waveform having no pause time is applied to the electrodes 2 and 3
By applying a voltage between them, a dielectric barrier discharge is generated in the discharge space 34 under the atmospheric pressure, and the plasma for generating the plasma is converted into a plasma by the dielectric barrier discharge to generate a plasma composed of a large number of streamers 11 containing plasma active species. The plasma was generated in the discharge space 34, and thereafter, the object 4 was introduced into the discharge space 34, and plasma was supplied to the surface of the object 4 to perform plasma processing (removal of organic substances).

The voltages shown in Table 1 were used as the alternating voltage waveforms with no pause time applied between the electrodes 2 and 3, and this voltage was applied between the electrodes 2 and 3 under the conditions shown in Table 1.

(Examples 2 to 4) The voltages shown in Table 1 were used as the alternating voltage waveforms having no pause time applied between the electrodes 2 and 3, and the voltages were applied to the electrodes 2 and 3 under the conditions shown in Table 1. Plasma treatment was performed in the same manner as in Example 1 except that the voltage was applied during the period.

Comparative Example 1 H was used as a plasma generating gas.
Plasma treatment was performed in the same manner as in Example 1 except that a glow discharge was generated in the discharge space 34 using e.

(Comparative Example 2) A plasma treatment was performed in the same manner as in Example 1 except that a voltage having a pause shown in FIG. 20 was used.

(Comparative Example 3) Rise time 250 μs
ec, plasma treatment was performed in the same manner as in Example 1 except that a voltage having an alternating voltage waveform without a pause time of 250 μsec was used.

With respect to Examples 1 to 4 and Comparative Examples 1 to 3, the uniformity of the plasma density in the discharge space 34, the uniformity of the plasma processing, and the performance of the plasma processing were evaluated.

The uniformity of the plasma density in the discharge space 34 was evaluated based on the variation in the light emission intensity during discharge.

The uniformity of the plasma treatment was evaluated based on the variation of the contact angle of the object 4 with water.

The performance of the plasma treatment was evaluated by the contact angle of the object 4 with water.

Table 1 shows the results.

[0076]

[Table 1]

As is clear from Table 1, in Examples 1 to 4 in which the plasma treatment was performed by the dielectric barrier discharge generated using dry air, the plasma treatment was performed in a very short time of 10 seconds or less. The contact angle of water on object 4 is about 45 °
To 5 ° or less, and the organic matter on the surface of the glass could be removed in a short time.

On the other hand, in Comparative Example 1 in which plasma processing was performed by a conventional glow discharge using He, the processing time was more than twice as long as in Examples 1 to 4 in which plasma processing was performed by dielectric barrier discharge. Was. Also, in Comparative Example 2 using only the voltage of the pulse-like waveform, a long-time plasma treatment was required. Further, in the case of Comparative Example 3 using a voltage having an alternating voltage waveform in which both the rise time and the fall time exceed 100 μsec, the uniformity of the plasma density and the uniformity of the plasma processing are low, and the time required for the plasma processing is very long. It became longer.

[0079]

As described above, according to the first aspect of the present invention, a discharge space is formed between the opposed electrodes.
A dielectric is provided on the discharge space side of at least one of the electrodes disposed opposite to each other, a gas for plasma generation is supplied to the discharge space, and a voltage is applied between the electrodes, so that the discharge space is formed under a pressure near the atmospheric pressure. In a plasma processing apparatus that generates a dielectric barrier discharge, the waveform of the voltage applied between the electrodes is an alternating voltage waveform having no pause, and the rising time of the alternating voltage waveform is 100 μsec or less. By performing the plasma processing using the dielectric barrier discharge, He is not required, the cost required for the plasma processing can be reduced, and the power input to the discharge space can be increased. The plasma density can be increased, and the plasma processing ability can be increased.
In addition, by setting the rise time to 100 μsec or less, the streamer is easily generated uniformly in the discharge space, and the uniformity of the plasma density in the discharge space can be increased, and uniform plasma processing can be performed. It is.

According to a second aspect of the present invention, a discharge space is formed between the opposed electrodes, and a dielectric is provided on at least one of the opposed electrodes in the discharge space side. In a plasma processing apparatus that generates a dielectric barrier discharge in a discharge space under a pressure near the atmospheric pressure by supplying a plasma generation gas to a space and applying a voltage between the electrodes, a waveform of a voltage applied between the electrodes is changed. Since the alternating voltage waveform has no pause and the fall time of the alternating voltage waveform is 100 μsec or less, He is not required by performing plasma processing using dielectric barrier discharge which is not glow discharge. The cost required for plasma processing can be kept low, and the power input to the discharge space can be increased, thus reducing the plasma density. And the fall time is set to 100 μsec or less, so that the streamer is easily generated uniformly in the discharge space, and the plasma in the discharge space is reduced. The uniformity of density can be increased, and uniform plasma processing can be performed.

According to the third aspect of the present invention, since the repetition frequency of the alternating voltage waveform is set to 0.5 to 200 kHz, arc and discharge contraction can be prevented and the plasma density of the dielectric barrier discharge can be reduced. It is possible to increase the plasma processing ability while preventing damage to the object to be processed and defective discharge.

According to the invention of claim 4 of the present invention, since the electric field intensity applied between the electrodes is set to 1 to 200 kV / cm, it is possible to prevent arcing and increase the plasma density of the dielectric barrier discharge. Thus, the capability of the plasma processing can be enhanced while preventing damage to the processing object.

Further, according to the invention of claim 5 of the present invention, since a pulse-like high voltage is superimposed on a voltage having an alternating voltage waveform with no pause applied between the electrodes, the electrons are accelerated in the discharge space and the high voltage is applied. High-energy electrons can be generated, and the high-energy electrons can efficiently ionize and excite the plasma-generating gas in the discharge space, thereby enabling high-density plasma to be generated. It can increase efficiency.

According to the invention of claim 6 of the present invention, the pulsed high voltage is superimposed after a predetermined time has elapsed from immediately after the voltage polarity of the alternating voltage waveform has changed. Therefore, by changing the timing of applying a pulsed high voltage between the electrodes, it is possible to control the ionization and excitation state of the plasma generation gas in the discharge space, and It is possible to easily create a plasma state suitable for the plasma processing.

According to the seventh aspect of the present invention, since a plurality of pulsed high voltages are superimposed in one cycle of the alternating voltage waveform, the acceleration state of electrons in the discharge space can be easily changed. Therefore, by changing the timing of applying a pulsed high voltage between the electrodes, it becomes easier to control the ionization and excitation state of the plasma generating gas in the discharge space, and to achieve desired plasma processing. Suitable plasma conditions can be more easily created.

According to the invention of claim 8 of the present invention, since the rising time of the pulsed high voltage is set to 0.1 μsec or less, it is possible to efficiently accelerate only the electrons in the discharge space, Thus, the plasma generation gas can be efficiently ionized and excited, and high-density plasma can be generated, so that the efficiency of plasma processing can be increased.

According to the ninth aspect of the present invention, since the peak value of the pulsed high voltage is set to be equal to or more than the maximum voltage value of the alternating voltage waveform, the plasma generating gas is efficiently ionized and excited in the discharge space. Therefore, high-density plasma can be generated, and the efficiency of plasma processing can be increased.

According to the tenth aspect of the present invention, an alternating voltage waveform having no pause time applied between the electrodes is formed by superimposing alternating voltage waveforms of a plurality of types of frequencies. The voltage accelerates the electrons in the discharge space to generate high-energy electrons, and the high-energy electrons can efficiently ionize and excite the plasma generation gas in the discharge space, thereby increasing the density. Can be generated, and the efficiency of the plasma processing can be increased.

According to the eleventh aspect of the present invention, since the plasma processing is performed using the plasma processing apparatus according to any one of the first to tenth aspects, the plasma processing is performed using a dielectric barrier discharge which is not a glow discharge. By performing the treatment, He is not required, so that the cost for the plasma treatment can be reduced, and the power input to the discharge space can be increased, and the plasma density can be increased. The plasma processing capability can be enhanced, and by setting the rise time and fall time to 100 μsec or less, the streamer is easily generated uniformly in the discharge space, and the plasma density in the discharge space becomes uniform. It is possible to enhance the property and perform a uniform plasma treatment.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of the present invention.

FIG. 2 is a schematic diagram showing an example of another embodiment of the embodiment.

FIG. 3 is a cross-sectional view showing the electrode of the above.

FIG. 4 is a schematic diagram of the above.

FIG. 5 is a schematic diagram of the above.

FIGS. 6A to 6E are schematic views showing the same operation.

FIG. 7 is a schematic diagram showing an example of another embodiment of the above.

FIG. 8 shows the operation of the above, and (a) to (d) are schematic views.

9A and 9B show an example of another embodiment of the present invention, wherein FIG. 9A is a schematic view and FIG. 9B is a side view.

FIGS. 10A to 10C show the operation of the above, and FIGS. 10A to 10C are schematic views.

FIGS. 11A and 11B show an arrangement of electrodes and a dielectric for generating a dielectric barrier discharge, and FIGS. 11A and 11B are cross-sectional views.

FIG. 12 is a cross-sectional view showing a state where a dielectric barrier discharge has occurred.

FIG. 13 shows a state in which a dielectric barrier discharge has occurred.
4 is a graph showing a change with time in an applied voltage and a gap current.

FIG. 14 is a circuit diagram showing an equivalent circuit of a dielectric barrier discharge.

FIG. 15 shows a state in which a dielectric barrier discharge has occurred.
6 is a graph showing a change over time in a power supply voltage, an equivalent capacitance Cg of a discharge space (discharge gap portion), and a plasma impedance Rp.

FIGS. 16A and 16B are cross-sectional views showing a state where the polarity of a power supply is reversed.

17 (a), (b) and (c) are explanatory diagrams showing examples of alternating voltage waveforms used in the present invention.

FIGS. 18A and 18B are explanatory diagrams showing waveforms in a state where a pulse-like high voltage is superimposed on a voltage having an alternating voltage waveform used in the present invention.

FIG. 19 is an explanatory diagram showing a waveform in a state where an alternating voltage waveform used in the present invention is formed by superimposing alternating voltage waveforms of a plurality of types of frequencies.

FIG. 20 is an explanatory diagram showing waveforms of voltages used in Comparative Example 2.

[Explanation of symbols]

 2 electrode 3 electrode 32 dielectric 34 discharge space

Continuing from the front page (72) Inventor Yasushi Sawada 1048 Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Works, Ltd. Inside (72) Inventor Koichi Matsunaga 465-1, Shimizu, Uozumi-cho, Akashi-shi, Hyogo Pref. Inventor Takeshi Yukimura F-term (reference) 6-45, Moriyama 6-chome, Moriyama-shi, Shiga 4G075 AA22 AA24 BC01 BC06 BC10 BD14 BD24 CA14 CA47 DA02 EB01 EB41 EC21 ED04 ED06 FB01 5F004 AA01 AA14 AA16 BA20 BB11 BB24 DA00 DA01 DB01 DB13 DB23 5F045 AA08 BB01 DP23 DQ15

Claims (11)

[Claims] 1. A discharge space is formed between opposed electrodes, a dielectric is provided on at least one of the opposed electrodes on the discharge space side, and a plasma generating gas is supplied to the discharge space. In addition, in a plasma processing apparatus that generates a dielectric barrier discharge in a discharge space under a pressure near the atmospheric pressure by applying a voltage between the electrodes, the waveform of the voltage applied between the electrodes is an alternating voltage waveform without a pause time. And the rise time of this alternating voltage waveform is set to 100
A plasma processing apparatus characterized in that the time is not longer than μsec. 2. A discharge space is formed between the opposed electrodes, a dielectric is provided on at least one of the opposed electrodes on the discharge space side, and a plasma generating gas is supplied to the discharge space. In addition, in a plasma processing apparatus that generates a dielectric barrier discharge in a discharge space under a pressure near the atmospheric pressure by applying a voltage between the electrodes, the waveform of the voltage applied between the electrodes is an alternating voltage waveform without a pause time. And the fall time of this alternating voltage waveform is set to 100
A plasma processing apparatus characterized in that the time is not longer than μsec. 3. The repetition frequency of the alternating voltage waveform is 0.5
The frequency is set to 200 kHz.
3. The plasma processing apparatus according to 1. 4. An electric field intensity applied between electrodes of 1 to 20
4. The plasma processing apparatus according to claim 1, wherein the pressure is set to 0 kV / cm. 5. The plasma processing apparatus according to claim 1, wherein a pulse-like high voltage is superimposed on a voltage having an alternating voltage waveform with no pause time applied between the electrodes. 6. The plasma processing apparatus according to claim 5, wherein a pulsed high voltage is superimposed after a lapse of a predetermined time immediately after the voltage polarity of the alternating voltage waveform changes. 7. The plasma processing apparatus according to claim 5, wherein a plurality of pulsed high voltages are superimposed in one cycle of the alternating voltage waveform. 8. The plasma processing apparatus according to claim 5, wherein a rising time of the pulsed high voltage is set to 0.1 μsec or less. 9. The plasma processing apparatus according to claim 5, wherein the peak value of the pulsed high voltage is equal to or more than the maximum voltage value of the alternating voltage waveform. 10. The method according to claim 1, wherein an alternating voltage waveform having no pause time applied between the electrodes is formed by superposing alternating voltage waveforms of a plurality of frequencies. Plasma processing equipment. 11. A plasma processing method, comprising performing plasma processing using the plasma processing apparatus according to claim 1.