JP2003217898A - Discharge plasma processing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a remote-type discharge plasma having an electrode structure capable of sufficiently enlarging a discharge space, inhibiting the generation of streamer discharge, performing the discharge capable of generating plasma of high density with small power, and inhibiting the deterioration of solid dielectric covering the electrode. <P>SOLUTION: In this discharge plasma processing device wherein the solid dielectric is mounted on at least one of opposite faces of electrodes opposite to each other under the pressure near the atmospheric pressure, and the discharge plasma obtained by introducing a processing gas and applying the electric field, is brought into contact with a processed object mounted outside of the discharge space to process the object, the opposite faces of the electrode have the approximately hog-backed shape formed by a convex curved face of a radius of curvature of 25 mm or more and 2000 mm or less. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atmospheric pressure plasma processing apparatus under a pressure near atmospheric pressure, and more particularly, to a counter electrode surface in an apparatus for performing atmospheric pressure plasma processing on an object to be processed which is located away from the discharge space. The present invention relates to a discharge plasma processing apparatus that can generate plasma stably with an appropriate radius of curvature.

[0002]

2. Description of the Related Art Conventionally, a method of generating a glow discharge plasma under a low pressure condition to modify the surface of an object to be processed or to form a thin film on the object to be processed has been put into practical use. However, the treatment under these low pressure conditions requires a vacuum chamber, a vacuum exhaust device, etc., and the surface treatment device becomes expensive, and it has hardly been used when treating a large area substrate or the like. Therefore, a method of generating discharge plasma under a pressure near atmospheric pressure has been proposed.

In a general atmospheric pressure plasma processing method, as described in JP-A-6-2149, JP-A-7-85997, etc., the inside of the processing tank is mainly covered with a solid dielectric or the like. The object to be processed is installed between the parallel plate electrodes, the processing gas is introduced into the processing tank, a voltage is applied between the electrodes, and the object to be processed is treated with the generated plasma. In these methods, flat electrodes are made to face each other in parallel, and an object to be processed is placed in a space between the electrodes to perform processing. Although it is easy, there is a problem that it tends to damage the object to be processed.

On the other hand, a remote plasma processing apparatus having a plasma gas outlet at its tip has been developed as an apparatus that can easily perform plasma processing only on a specific portion of an object to be processed and can continuously process the object. Has been done. The remote type is a type that blows out the plasma generated between the electrodes toward the object to be processed located outside the discharge space.It reduces damage to the object to be processed, but it is similar to the conventional type. In that case, there is a problem that the treatment strength is difficult to obtain, and a higher density plasma is required. Such a device, particularly, when plasma is generated by parallelly facing electrodes whose planes are opposed to each other in parallel, uniform high density plasma cannot be obtained with low power, and streamer discharge or the like is likely to occur. There was a problem.

As one means for solving this problem, in Japanese Unexamined Patent Publication No. 2000-200697, a rare gas is used as a processing gas, and a dielectric having a curved surface with a radius of curvature of 1 to 25 mm projected into a discharge space is coated. There is disclosed a technique in which a plasma is generated by applying an AC voltage using the above electrode and a streamer discharge is prevented from occurring.
However, if a cylindrical electrode with a small radius of curvature is used, the electric field concentration is too strong and streamer discharge is likely to occur, and the discharge space through which the processing gas passes becomes short, resulting in insufficient activation. There's a problem.
Further, since the discharge on the electrode is local, the dielectric covering the electrode is likely to be deteriorated, and this deteriorated portion induces streamer discharge. Furthermore, since the cylindrical electrode with a small curvature has a small amount of electrode aggregate due to its configuration,
It is easy to be deformed by heat in the process of fusing and spraying glassy or ceramic dielectrics, and it is difficult to make the electrode gap constant. Furthermore, as the length of the electrode becomes longer, the problem of the deformation cannot be ignored, so that there is a problem that it is difficult to deal with a large area process.

[0006]

In view of the above problems, the present invention is capable of sufficiently increasing the discharge space, suppressing the generation of streamer discharges, and enabling discharges that generate high-density plasma with low power, and It is an object of the present invention to provide a remote type discharge plasma processing apparatus having an electrode structure capable of suppressing deterioration of a solid dielectric covering an electrode.

[0007]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above problems, the present inventor has made it possible to sufficiently increase the discharge space by using a substantially semi-cylindrical shape in which the radius of curvature of the facing electrode surface is increased. The inventors have found that an electrode structure capable of suppressing the occurrence of streamer discharge, generating high-density plasma with low power, and suppressing the deterioration of the solid dielectric covering the electrode can be obtained, and completed the present invention.

That is, according to the first aspect of the present invention, a solid dielectric is provided on at least one opposing surface of opposing electrodes under a pressure near atmospheric pressure, and a processing gas is introduced between the electrodes to apply an electric field. A discharge plasma processing apparatus that processes discharge plasma obtained by contacting an object to be processed arranged outside the discharge space, wherein the electrode has a convex surface with a facing radius of more than 25 mm and 2000 mm or less. The discharge plasma processing apparatus is characterized by having a substantially semicylindrical shape formed by a curved surface.

According to a second aspect of the present invention, the electrode is cut into a substantially semi-cylindrical shape whose opposing surface is formed by a convex curved surface having a radius of curvature of more than 25 mm and 2000 mm or less, and is substantially parallel to the surface to be processed. The discharge plasma processing apparatus according to the first invention is characterized in that it has a semi-cylindrical shape so as to form a surface.

A third invention of the present invention is the discharge plasma processing apparatus according to the first or second invention, wherein the angle formed by the electrodes is variable.

A fourth invention of the present invention is the discharge plasma according to any one of the first to third inventions, characterized in that the corners of the boundary between the facing surface and the side surface of the electrode are curved. It is a processing device.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION In a discharge plasma processing apparatus of the present invention, a solid dielectric is provided on at least one opposing surface of opposing electrodes under a pressure near atmospheric pressure, and a processing gas is introduced between the electrodes to generate an electric field. A discharge plasma processing apparatus for performing plasma processing on an object to be processed which is arranged at a position apart from an electrode structure (hereinafter, sometimes referred to as a remote source) for generating glow discharge plasma by applying The electrode used for is characterized in that the opposing surface has a substantially semicylindrical shape composed of convex curved surfaces.

The device of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view illustrating a processing apparatus for an object to be processed using a remote source of the present invention. In FIG. 1, the opposing electrodes 2 and 3 have convex curved surfaces 21 and 31 at their opposing surfaces.
It is a substantially semi-cylindrical electrode composed of. In the plasma treatment, a treatment gas is introduced in an arrow direction into a discharge space 4 composed of an electrode 2 and an electrode 3, an electric field is applied to the electrodes 2 and 3 from a power source 1 to generate plasma in the discharge space 4, Plasma is blown out from the plasma blowout port and blown onto the surface of the object 5 to be processed on the support 6.

Here, the kamaboko shape refers to a shape in which one surface of a rectangular parallelepiped is formed by a gentle bow-shaped curved surface, the center of which is swollen and both sides are gradually lowered. In the electrode used in the present invention, the curved surface has a radius of curvature of 25 mm or more.
It is necessary to form a gentle curved surface of 000 mm or less, preferably 40 to 1000 mm, and by causing the curved surfaces to face each other to generate plasma, stable discharge can be performed with a small electric power. When the radius of curvature is 25 mm or less, electric field concentration is strong, so that streamers are likely to occur, and when it exceeds 2000 mm, processing becomes difficult in terms of accuracy.

In the electrode of the apparatus of the present invention, this curved surface is arranged as an electrode facing surface, and the introduction and blowing directions of the processing gas are provided in the circumferential direction of the curved surface. Since the opposing surface is an appropriately curved surface, the discharge is likely to be stable, and the discharge space becomes large, so that plasma activation is further promoted and deterioration of the dielectric can be suppressed.

In addition, it is preferable that the substantially semi-cylindrical electrode has a curved surface at the corner of the boundary between the electrode facing surface and the side surface. It will be described with reference to FIG. 2, which is a perspective view of a substantially semicylindrical electrode of the electrode 2. In FIG. 2, the short side ends 22 and 23 of the convex curved surface 21 having a gentle bow shape have a radius of curvature (hereinafter, indicated as R) of 2 mm to 100 mm, preferably 4 m.
It is preferable that the curved surface is processed so as to be m to 20 mm. When the short side end is less than R2 mm, electric field concentration occurs and streamers are likely to occur, and when R100 mm is exceeded, the streamer is hard to stand, but the effect remains the same. Further, the long side end portions 24 and 25 of the convex curved surface 21 are R
2 mm to R20 mm, preferably R4 mm to R20 mm
The curved surface is preferably processed so that If the end portion of the long side is less than R2 mm, electric field concentration tends to occur and streamers are likely to occur. If it exceeds R20 mm, the streamer becomes difficult to stand, but the effect remains the same. The same applies to the electrode 3.

When discharge plasma treatment is performed using the apparatus of FIG. 1, plasma discharge can be performed with a small amount of electric power, the discharge space through which the treatment gas passes is sufficiently activated, and is easily activated. Further, generation of streamers can be suppressed and the electrode Deterioration of the solid dielectric coated on the surface is also suppressed. Furthermore, since the amount of the electrode aggregate is large, even when the solid dielectric is coated on the electrode surface by fusion bonding or thermal spraying, deformation due to processing heat is small and a long product can be manufactured.

FIG. 3 is a schematic cross-sectional view for explaining a processing apparatus for processing an object using a remote source for explaining the second example of the present invention. The opposing electrode 2 and electrode 3 are
The apparatus is a single-sided, semi-cylindrical electrode obtained by cutting the generally semi-cylindrical electrode shown in FIG. 1, and is installed so that the curved surface 21 and the curved surface 31 are opposed to each other to form a surface substantially parallel to the surface to be processed. The processing gas is introduced in the direction of the arrow into the discharge space 4 composed of the electrodes 2 and 3, an electric field is applied from the power supply 1 to the electrodes 2 and 3, plasma is generated in the discharge space 4, and the plasma is discharged from the plasma outlet. Plasma is blown out to process the surface of the object 5 to be processed on the support 6.

Also in the one-sided semi-cylindrical electrode, the radii of curvature of the opposing curved surfaces 21 and 31 are the same as in the case of the first invention, and the corners of the short side end and the long side end of the curved surface are the same. Is preferably curved. In addition to the features of the first invention, the one-sided, semi-cylindrical electrode of the second invention of the present invention has the effect of narrowing the diameter of the plasma outlet, and can easily increase the flow velocity of the blown plasma.

FIG. 4 is a schematic cross-sectional view for explaining an apparatus for processing an object to be processed using a remote source for explaining the third example of the present invention. The opposing electrode 2 and electrode 3 are
The opposing surface is a substantially semi-cylindrical electrode having a curved surface, and the fixed angle in the vertical direction is variable. FIG. 3 (a) is a diagram showing an example of a remote source in which the angle is changed so that the upper electrode spacing is narrowed, and FIG. 3 (b) is a remote source in which the angle is changed so that the lower electrode spacing is narrowed. FIG. 3C is a diagram showing an example of a remote source when the electrode spacing is adjusted. In each figure, the processing gas is introduced in the direction of the arrow into the discharge space 4 formed between the electrodes 2 and 3, and an electric field is applied from the power supply 1 to the electrodes 2 and 3 to generate plasma in the discharge space 4. The plasma is blown out from the plasma blowing port to treat the surface of the target object 5. In FIG. 3 (a), the plasma outlet can be increased, which is effective for treating a large-area substrate. In FIG. 3 (b), the plasma outlet can be decreased and the plasma flow velocity can be increased. 3C, the electrode spacing is adjusted by changing the angle according to the purpose. As described above, in the device of the third invention of the present invention, by making the fixed angle of the electrodes in the vertical direction variable, in addition to the features of the first invention, the gas flow velocity affecting the plasma processing effect can be adjusted, It has a characteristic that the deterioration of the solid dielectric can be controlled by changing the portion of the electrode corresponding to the discharge. That is, in the apparatus of the present invention, the angle formed by the electrodes is made variable, so that the discharge can be adjusted and the plasma spraying angle and speed of the plasma to the object can be easily adjusted. In particular, the inter-electrode distance needs to be adjusted depending on the environment such as the gas atmosphere and the temperature, but with the electrode shape of the present invention, the inter-electrode distance can be adjusted simply by changing the angle, and therefore the adjustment is performed by a simple operation. be able to.

Also in the third invention, the curvature radii of the opposed curved surfaces 21 and 31 of the substantially semicylindrical electrode are as follows:
It is similar to the case of the first aspect of the invention, and it is preferable that the corners of the short side ends and the long side edges of the curved surface are subjected to the same curved surface treatment as in the case of the first invention.

Regarding the size of the substantially semicylindrical electrode used in the present invention, the short side of the generally semicylindrical shape (a in FIG. 2) is used.
Is 10 to 300 mm and the long side (b in FIG. 2) is 20 to 250
It is preferably 0 mm and the peak height (c in FIG. 2) is 10 to 100 mm. Examples of the material of the electrodes include those made of simple metals such as copper and aluminum, alloys such as stainless steel and brass, and intermetallic compounds.

The distance between the electrodes is determined by the thickness of the solid dielectric,
Although it is appropriately determined in consideration of the magnitude of the applied voltage, the purpose of utilizing plasma, etc., it is preferably 0.1 to 50 mm, more preferably 0.1 to 5 mm. 0.1
If it is less than mm, it may not be enough to install the electrodes with a space therebetween, while if it exceeds 50 mm, it is difficult to generate uniform discharge plasma.

The opposing electrodes are not limited to a pair,
By disposing a plurality of electrodes facing each other, a plurality of discharge spaces can be provided. By providing a plurality of discharge spaces, plasma of a large amount of processing gas can be generated and high-speed processing can be performed.

The above-mentioned solid dielectric must be installed on one or both of the facing surfaces of the electrodes. The solid dielectric is in close contact with the electrodes so as to completely cover the facing surfaces of the electrodes. If there is a portion where the electrodes directly face each other without being covered with the solid dielectric, arc discharge easily occurs from there.

The above solid dielectric has a thickness of 0.01 to 4 m.
It is preferably m. If it is too thick, a high voltage may be required to generate discharge plasma, and if it is too thin, dielectric breakdown may occur when a voltage is applied and arc discharge may occur.

Examples of the material of the solid dielectric include plastics such as polytetrafluoroethylene and polyethylene terephthalate, glass, metal oxides such as silicon dioxide, aluminum oxide, zirconium dioxide and titanium dioxide, and double oxidation such as barium titanate. Things etc. are mentioned.

Particularly, the relative permittivity under the environment of 25 ° C. is 1
If a solid dielectric material of 0 or more is used, a high density discharge plasma can be generated at a low voltage, and the processing efficiency is improved. The upper limit of the relative permittivity is not particularly limited, but as a practical material, about 18,500 is available and can be used in the present invention. A solid dielectric having a relative dielectric constant of 10 to 100 is particularly preferable. Specific examples of the solid dielectric having a relative dielectric constant of 10 or more include metal oxides such as zirconium dioxide and titanium dioxide, and complex oxides such as barium titanate.

In the present invention, an electric field of high frequency, pulse wave, microwave or the like is applied between the electrodes to generate plasma, but it is preferable to apply the pulse electric field.
In particular, the rise and / or fall time of the electric field is
An electric field of 10 μs or less is preferred. If it exceeds 10 μs, the discharge state easily shifts to an arc and becomes unstable, and it becomes difficult to maintain the high-density plasma state due to the pulsed electric field. Further, the shorter the rise time and the fall time are, the more efficiently the gas is ionized at the time of plasma generation, but it is actually difficult to realize a pulsed electric field having a rise time of less than 40 ns. More preferably 5
It is 0 ns to 5 μs. Note that the rising time referred to here means the time when the voltage (absolute value) continuously increases, and the falling time means the time when the voltage (absolute value) continuously decreases.

The electric field strength of the pulsed electric field is 10 to 10
It is preferably set to 00 kV / cm. If the electric field strength is less than 10 kV / cm, the treatment takes too long, and if it exceeds 1000 kV / cm, arc discharge is likely to occur.

The frequency of the pulsed electric field is 0.5 kHz.
The above is preferable. If it is less than 0.5 kHz, the plasma density is low and the treatment takes too long. The upper limit is not particularly limited, but is commonly used 13.56M
A high frequency band such as Hz or a test-use 500 MHz may be used. Considering the ease of matching with the load and the handling property, the frequency is preferably 500 kHz or less. By applying such a pulsed electric field, the processing speed can be greatly improved.

Further, one pulse duration in the above pulsed electric field is preferably 200 μs or less. If it exceeds 200 μs, arc discharge is likely to occur. Here, one pulse duration is ON, OF
It means the continuous ON time of one pulse in the pulse electric field composed of the repetition of F.

The discharge plasma processing apparatus of the present invention can be used under any pressure, but when it is used for normal pressure discharge plasma processing for generating glow discharge plasma under a pressure near atmospheric pressure, its effect is sufficiently exerted. Can be demonstrated. The apparatus of the present invention is particularly advantageous in the atmospheric pressure discharge plasma treatment because it requires a higher voltage than the treatment under a low pressure.

The above-mentioned pressure near the atmospheric pressure means 1.333.
It refers to under a pressure of × 10 ^{4 to} 10.664 × 10 ⁴ Pa. Among them, the pressure adjustment is easy, and the device is simple.
The range of × 10 ^{4 to} 10.397 × 10 ⁴ Pa is preferable.

The object to be treated in the present invention includes polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, polytetrafluoroethylene, polyimide, liquid crystal polymer, epoxy resin, acrylic resin, resist resin and other plastics,
Examples thereof include glass, ceramic, metal, silicon substrate and the like. Examples of the shape of the object to be processed include a plate shape and a film shape, but are not particularly limited thereto. According to the present invention, it is possible to easily deal with processing of objects to be processed having various shapes. For example, it can be used for plasma treatment such as substrate cleaning, surface treatment, ashing, etching, descum, desmear, thin film formation, and sterilization.

The processing gas used in the present invention is not particularly limited as long as it is a gas that generates plasma by applying an electric field, and various gases can be used depending on the processing purpose.

As the processing gas, CF ₄ , C ₂ F ₆ ,
A water repellent surface can be obtained by using a fluorine-containing compound gas such as CClF ₃ or SF ₆ .

Further, as the processing gas, O ₂ , O ₃ , water,
Hydrophilicity of carbonyl group, hydroxyl group, amino group, etc. on the surface of the base material by using oxygen element-containing compounds such as air, nitrogen element-containing compounds such as N ₂ , NH ₃ and sulfur element-containing compounds such as SO ₂ , SO ₃ A hydrophilic surface can be obtained by forming a functional group to increase the surface energy. Further, the hydrophilic polymer film can be deposited by using a polymerizable monomer having a hydrophilic group such as acrylic acid or methacrylic acid.

Further, by using a processing gas such as a metal-hydrogen compound of a metal such as Si, Ti or Sn, a metal-halogen compound or a metal alcoholate, SiO ₂ , TiO ₂ or SnO is used.
A metal oxide thin film such as ₂ is formed and is electrically and
Optical function can be given, and halogen gas is used for etching and dicing, oxygen gas is used for resist treatment and removal of organic contaminants, and inert gas such as argon and nitrogen is used. Surface cleaning and surface modification can also be performed with plasma.

From the viewpoint of economy and safety, it is possible to carry out the treatment in an atmosphere diluted with the above-mentioned treatment gas by the following diluent gas. As a diluent gas,
Examples of the rare gas include helium, neon, argon, xenon, and nitrogen gas. You may use these individually or in mixture of 2 or more types. The mixing ratio of the diluting gas varies depending on the application, but for example, when forming a hydrophilic biopolymer film or a metal oxide thin film, the ratio of the processing gas is 0.01 to 10.
Volume% is preferred.

The plasma processing apparatus of the present invention may be provided with an exhaust gas exhaust mechanism for rectifying the plasma flow and collecting exhaust gas.

[0042]

EXAMPLES The present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

Example 1 A resist ashing process was performed using an electrode having the shape shown in FIG. The counter electrode is a one-sided, semi-cylindrical electrode with a long side of 700 mm, a short side of 50 mm, and a mountain height of 40 mm, the surface of which is coated with alumina having a thickness of 1.0 mm and which is cooled with water. R10mm at the long side end corner of the facing surface, R5m at the short side end corner
A SUS single-sided semi-cylindrical electrode having a curved surface treated to m was used, and the distance between the curved top points of the opposed surfaces was set to 1.0 mm. Using a mixed gas of N ₂ / O ₂ = 98/2 (volume%) as a processing gas, a substrate having a residual resist on a 370 mm × 470 mm square Cr-coated glass was placed at a distance of 5 mm from a plasma outlet at 100 mm / It was transported for min, and an ashing process was performed by applying an electric field having V _{PP of} 30 kV, a frequency of 50 KHz, and a pulse rising speed of 5 μs between the electrodes. As a result, the ashing treatment was uniformly performed on the entire surface of the base material, and the ashing amount was 1.5 μm.

Example 2 A printed board was washed using the electrodes having the shape shown in FIG. The opposite electrode is a substantially semi-cylindrical electrode having a long side of 150 mm, a short side of 30 mm, and a mountain height of 20 mm, which is formed by coating the surface with alumina having a thickness of 1.0 mm and cooling the inside with water. R10 mm at the long side end corner of the facing surface, R5 mm at the short side end corner
The SUS-made substantially semi-cylindrical electrode having been subjected to the curved surface was used, and the distance between the shortest portions of the opposed curved surfaces was set to 0.5 mm. N ₂ gas was used as a processing gas, and a distance of 3.5 mm from a 120 mm × 50 mm square printed circuit board plasma outlet having a solder resist or gold wiring on the surface was used.
Transported at 00 mm / min, V _PP 20 kV between electrodes,
A cleaning process was performed by applying an electric field having a frequency of 20 KHz and a pulse rising speed of 5 μs. As a result, the entire surface of the base material was uniformly washed, and the adhesiveness to the sealing material was 5 times and the wire bonding strength was 2.5 times that of the untreated product.

Example 3 Using the electrode having the shape shown in FIG. 3 (b), the polymer film was subjected to hydrophilicity improving treatment. The counter electrode is 1.0 on the surface.
mm-shaped electrode coated with mm-thick alumina and cooled inside with water having a long side of 1300 mm, a short side of 200 mm, and a mountain height of 50 mm.
000 mm, the long side end corners of the electrode facing surface are R50 mm,
Using a substantially cylindrical electrode made of SUS whose short side end corners are curved to R20 mm, the curved surfaces facing each other are tilted inward by 20 degrees from the state parallel to each other, and the distance of the top is 1. It was set to 5 mm. Argon gas is used as a processing gas, and the width is 1000 mm × the length 100 mm × the thickness is 0.1 mm.
A 04 mm roll-shaped polyimide film was conveyed at a distance of 1 mm from the plasma outlet at 500 mm / min, and an electric field of V _PP 6 kV, frequency 10 KHz, and pulse rising speed 5 μs was applied between the electrodes for surface treatment. As a result, the hydrophilic property was uniformly imparted to the entire surface of the film, and the result of the wettability evaluation with water was that the contact angle was 5 degrees or less, which was very effective.

[0046]

According to the discharge plasma processing apparatus of the present invention, the discharge space can be made sufficiently large, the generation of streamer discharge can be suppressed, the discharge can generate the high density plasma with a small electric power, and the electrode can be covered. It is a remote type discharge plasma processing apparatus having an electrode structure capable of suppressing deterioration of a solid dielectric. Therefore, it can be effectively used to realize in-line and high-speed processing in various plasma processing methods including various methods applicable to high-speed processing and large-area processing and used in semiconductor manufacturing processes.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view illustrating a plasma discharge processing apparatus of the present invention.

FIG. 2 is a schematic sectional view illustrating an electrode of the plasma discharge treatment apparatus of the present invention.

FIG. 3 is a schematic cross-sectional view illustrating a plasma discharge processing apparatus of the present invention.

FIG. 4 is a schematic cross-sectional view illustrating a plasma discharge processing apparatus of the present invention.

[Explanation of symbols]

1 power supply A few electrodes 4 discharge space 5 Object to be processed 6 support 21, 31 Electrode curved surface 22, 23, 24, 25 Electrode end corners

Claims (4)

[Claims] 1. A discharge plasma obtained by placing a solid dielectric on at least one opposing surface of opposing electrodes under a pressure near atmospheric pressure, introducing a processing gas between the electrodes, and applying an electric field, It is a discharge plasma processing apparatus which processes by making it contact with the to-be-processed object arrange | positioned outside discharge space, Comprising: The said electrode has a curvature radius of 25 mm over 2000 m.
A discharge plasma processing apparatus having a substantially semicylindrical shape formed by a convex curved surface of m or less. 2. A piece of an electrode, which is formed by cutting a substantially semi-cylindrical shape whose opposing surface is formed by a convex curved surface having a radius of curvature of more than 25 mm and 2000 mm or less to form a surface substantially parallel to the surface to be processed. The discharge plasma processing apparatus according to claim 1, wherein the discharge plasma processing apparatus has a semicylindrical shape. 3. The discharge plasma processing apparatus according to claim 1, wherein an angle formed by the electrodes is variable. 4. The discharge plasma processing apparatus according to claim 1, wherein a corner portion of a boundary between the facing surface and the side surface of the electrode is curved.