JP2003093870A - Discharge plasma treatment apparatus and discharge plasma treatment method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge plasma treatment apparatus having roll electrodes which can stably treat a long substrate to be treated with discharge plasma, and a discharge treatment method using the apparatus. SOLUTION: The discharge plasma treatment apparatus treats the substrate with glow discharge plasma generated by applying an electric field between a pair of the roll electrodes where at least one of the opposite surfaces of the electrodes is coated with a solid dielectric material. Process gas is introduced between the roll electrodes while rotating them, and the substrate is set between the electrodes to be treated. The discharge plasma treatment method uses the discharge plasma treatment apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge plasma processing apparatus, and more particularly to a discharge plasma processing apparatus having a roll electrode whose electrode rotates and a discharge plasma processing method using the same.

[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 processing apparatus under these low-pressure conditions requires a vacuum chamber, a vacuum exhaust apparatus, etc., and the surface processing apparatus becomes expensive, and it has hardly been used when processing a large area substrate or the like. Therefore, JP-A-6-2149
Japanese Patent Laid-Open No. 7-85997 and Japanese Patent Laid-Open No. 7-85997 propose an atmospheric pressure plasma processing apparatus for generating discharge plasma under a pressure near atmospheric pressure.

In such a processing method, an object to be processed is installed between parallel plate type electrodes covered with a solid dielectric, etc., a processing gas is introduced between the electrodes, and a voltage is applied between the electrodes. An apparatus that processes the object to be processed with the generated plasma is used. Since it is difficult to generate a uniform plasma over the entire surface of the parallel plate type electrode, when processing a long object, a roll-roll electrode is used, in which an electric field can be more concentrated and high density plasma can be easily generated. It may be preferred. However, while the roll-roll electrode is advantageous in increasing the density of plasma due to the property that the electric field is easily concentrated, it is easy to pass a current and therefore easily move to arc discharge. There was a problem to do.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the present invention uses a discharge plasma processing apparatus having a roll-roll electrode capable of stably performing discharge plasma processing on a long substrate to be processed, and a use thereof. It is an object of the present invention to provide a conventional discharge plasma processing method.

[0005]

As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that by rotating the electrodes during discharge treatment, the gas flow generated by the rotation is effective in suppressing the generation of current paths. That is, the present invention has been completed.

That is, the first invention of the present invention is an apparatus for treating a substrate with glow discharge plasma generated by applying an electric field between a pair of roll electrodes whose surface is coated with a solid dielectric. The discharge plasma processing apparatus is characterized in that a processing gas is introduced between the electrodes while rotating the roll electrode, and a substrate is positioned between the electrodes for processing.

A second invention of the present invention is the discharge plasma processing apparatus according to the first invention, wherein the rotation speed of the roll electrode is 5 to 10,000 rpm.

A third aspect of the present invention is characterized in that the pair of roll electrodes is a combination of clockwise and counterclockwise rotations so as to rotate in the conveying direction of the substrate. 1 is a discharge plasma processing apparatus according to the invention.

A fourth invention of the present invention is the discharge plasma processing apparatus according to any one of the first to third inventions, characterized in that the flow velocity of the processing gas is 0.1 m / sec or more. .

Further, a fifth invention of the present invention is characterized in that it is provided with a gas supply nozzle conforming to the shape of the electrode.
4 is a discharge plasma processing apparatus according to any one of 4th invention.

Further, a sixth invention of the present invention is characterized in that it is provided with a gas exhaust nozzle conforming to the shape of the electrode.
5 is a discharge plasma processing apparatus according to any one of 5th aspect of the invention.

A seventh invention of the present invention uses the discharge plasma processing apparatus according to any one of the first to sixth inventions,
Pulse rise and / or fall time is 10 μs
Hereinafter, a discharge plasma processing method is characterized in that a pulse electric field having an electric field strength of 10 to 1000 kV / cm is applied and the substrate is treated with glow discharge plasma generated.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention has a pair of roll-roll electrodes for generating glow discharge plasma by applying an electric field, and the surface of the roll-roll electrodes is coated with a solid dielectric, Each roll electrode is a device that is configured to rotate during discharge processing, and a processing gas is introduced between the roll-roll electrodes, an electric field is applied between the electrodes, and the generated glow discharge plasma is placed between the electrodes. It is an apparatus adapted to process a substrate to be processed. The present invention will be described in detail below.

An example of the apparatus used in the present invention will be described with reference to the drawings. FIG. 1 is a schematic device diagram illustrating a discharge plasma processing device having a pair of roll electrodes of the present invention. In FIG. 1, the surface of the roll electrode 2 and the roll electrode 3 is covered with solid dielectrics 7 and 7 ', a discharge space 4 is formed between them, and each roll electrode is adapted to rotate.
The processing gas is blown into the discharge space 4 from the outlet of the gas supply nozzle 5 in the arrow direction. When an electric field is applied between the roll electrodes 2 and 3 from the power supply 1, the processing gas is turned into plasma in the discharge space 4 to process the surface of the substrate 10 to be processed which is conveyed between the electrodes. The treated gas is sucked into the gas exhaust nozzle 6 and collected.

In the apparatus of the present invention, the rotation speed of the roll electrodes 2 and 3 is preferably 5 to 10000 rpm, more preferably 20 to 1000 rpm. If the rotation speed is less than 5 rpm, the discharge is not stable, and a speed exceeding 10,000 rpm is not realistic. Further, the rotation directions of the roll electrodes 2 and 3 may be the same direction rotation or different direction rotations, respectively, but clockwise and counterclockwise so as to rotate in the conveyance direction of the substrate 10 to be processed. The combination of is preferable because the gas flow can be made uniform. By rotating the roll electrodes 2 and 3, local deterioration of the solid dielectric provided on the electrode surface can be prevented, stable discharge can be maintained, and the life of the electrode can be remarkably extended.

In the apparatus of the present invention, the substrate 10 to be treated is
Are conveyed so as to be located between the roll electrodes 2 and 3. By positioning it between the electrodes, effective active species can be efficiently applied to the surface of the substrate to be treated. Double-sided treatment is possible by floating the traveling substrate in the discharge space 4 and traveling, and single-sided treatment is also possible by traveling while contacting one roll electrode.

In the apparatus of the present invention, the flow velocity of the processing gas introduced into the discharge space is preferably 0.1 m / s or more,
It is more preferably 0.5 to 50 m / sec. If the flow velocity of the processing gas is less than 0.1 m / sec, a current path is likely to be formed and the discharge becomes unstable, which is not preferable. Further, the processing gas is introduced into the discharge space from the gas supply nozzle 5, but the gas supply nozzle 5 is preferably a nozzle having a concave portion having a curvature corresponding to the curvature of the electrode. It is preferable that 5 is a nozzle having a shape that doubles as a guide mechanism. Further, the treated gas is preferably sucked and collected from the gas exhaust nozzle 6, and the gas exhaust nozzle 6 is preferably a nozzle having a concave portion having a curvature corresponding to the curvature of the electrode,
Furthermore, it is preferable that the gas exhaust nozzle 6 is a nozzle having a shape that also serves as a guide mechanism.

Although not shown, the substrate 1 to be treated
If the base material is a film-like one, the conveying means of 0 uses a conveying system consisting of a payout roll and a winding roll,
If it is a single sheet, a transfer system such as a transfer conveyor or a transfer robot can be used. In addition, an XY table or an XYZ table on which the base material is held is provided in the transport device,
An example of the device includes a control device that moves the XY table or the XYZ table so that the plasma gas is blown to the portion to be processed of the base material. Further, a guide roller may be provided before and after the plasma processing section, or a tension control mechanism or a crown roll may be provided to prevent wrinkles in the discharge section.

Examples of the material of the above-mentioned roll electrode 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 roll electrodes is appropriately determined in consideration of the thickness of the solid dielectric material coated thereon, the magnitude of the applied voltage, the purpose of utilizing plasma, etc., but is preferably 0.1 to 50 mm. . More preferably, it is 0.1 to 5 mm. 0.1 mm
If it is less than 50 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 surface of the roll electrode for generating plasma must be covered with a solid dielectric. On this occasion,
The solid dielectric and the electrode are in close contact with each other, and the opposite surface of the contacting electrode is completely covered. 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 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.

In particular, the relative dielectric constant 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 device of 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 a pulsed electric field, and in particular, rise of the electric field and / or Alternatively, an electric field having a fall time of 10 μs or less is preferable. 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. It is more preferably 50 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 pulse electric field is 10 to 10
It is preferably set to 00 kV / cm, more preferably 15 to 1000 kV / cm. If the electric field strength is less than 10 kV / cm, it takes too long to process,
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, its effect can be sufficiently exerted, especially under pressure near atmospheric pressure. When used, its effect is fully exerted.

The pressure under the atmospheric pressure is 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.

It is known that under a pressure in the vicinity of the atmospheric pressure, except for a specific gas such as helium or ketone, the plasma discharge state is not maintained stably and the arc discharge state is instantaneously transferred. It is considered that a cycle of stopping the discharge before starting the arc discharge and restarting the discharge is realized by applying the electric field of.

As the substrate to be treated in the present invention,
Examples thereof include plastics such as polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, polytetrafluoroethylene, polyimide, liquid crystal polymer, epoxy resin and acrylic resin, glass, ceramic, metal, fiber, paper and the like. Examples of the shape of the base material include a plate shape and a film shape, and particularly for semiconductor applications, a copper clad laminate, a printed board, a prepreg and the like can be mentioned.

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 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, using a processing gas such as a metal-hydrogen compound, a metal-halogen compound, a metal alcoholate of a metal such as Si, Ti or Sn, SiO ₂ , TiO ₂ , 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 viewpoints of economy and safety, it is preferable to perform the treatment in an atmosphere diluted with a diluent gas as described below, rather than the atmosphere for the treatment gas alone. As the diluent gas, helium, neon, argon,
Examples include rare gases such as xenon, nitrogen gas, and the like. You may use these individually or in mixture of 2 or more types. When a diluting gas is used, the ratio of the processing gas is 0.01 to 1
It is preferably 0% by volume.

According to the apparatus of the present invention, glow discharge plasma can be generated regardless of the type of gas existing in the plasma generation space. Not only plasma treatment under known low-pressure conditions, but also atmospheric pressure plasma treatment under a specific gas atmosphere, it was essential to perform treatment in a closed container shielded from the outside air, but glow discharge plasma of the present invention According to the method using the processing device,
It is possible to perform processing in an open system or in a low airtight system that prevents free flow of gas.

According to the atmospheric pressure discharge processing apparatus using the pulsed electric field of the present invention, it is possible to cause the discharge directly between the electrodes under the atmospheric pressure without depending on the gas species at all, which is further simplified. It is possible to realize high-speed processing with an electrode structure, an atmospheric pressure plasma device by a discharge procedure, and a processing method. In addition, parameters related to processing can be adjusted by parameters such as pulse frequency, voltage, and electrode interval.

[0039]

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 discharge plasma treatment was carried out using the apparatus shown in FIG. As electrodes 2 and 3, 1 mm of alumina is used as a solid dielectric on the outer surface of a 100 mmφ × 600 mm stainless steel cylinder.
Using a pair of roll electrodes coated by thermal spraying, the roll electrodes were installed at an interval of 2 mm, and the upper roll electrode 2 was rotated counterclockwise and the lower roll electrode 3 was rotated clockwise at 20 rpm. As the substrate 10 to be treated, thickness 50 μm × width 50
Transport speed of 0 mm polyimide film 100 mm / m
It was conveyed between the electrodes in. As the processing gas, dry air was blown from the gas supply nozzle 5 into the discharge space at a gas flow rate of 2 m / sec. A pulsed electric field having a pulse rise time of 3 μs, a voltage of 20 kV _PP and a frequency of 10 kHz was applied between the electrodes to perform plasma treatment on the surface of the polyimide film. It was confirmed that the discharge state was good and that the surface of the polyimide film was uniformly processed in the width direction to impart wettability.

Example 2 A substrate was treated in the same manner as in Example 1 except that the diameter of the roll electrode was 50 mm, the rotation number of the roll electrode was 2000 rpm, and the flow rate of the processing gas was 40 m / sec.
It was confirmed that the discharge state was good and that the surface of the polyimide film was uniformly processed in the width direction to impart wettability.

Example 3 The substrate was treated in the same manner as in Example 1 except that a prepreg was used as the substrate. It was confirmed that the discharge state was good, the surface of the base material was uniformly processed in the width direction, and the resin residue was removed.

Comparative Example 1 A substrate was treated in the same manner as in Example 1 except that the diameter of the roll electrode was 50 mmφ, the roll electrode was not rotated, and the flow rate of the processing gas was 0.05 m / sec. . The discharge state was non-uniform, streamers were generated in places, and traces of dents were found on the surface of the polyimide film.

[0044]

Since the discharge plasma processing apparatus of the present invention has a rotating roll electrode, it can generate a uniform high density plasma and has a large area substrate which is a continuous long substrate to be processed. Since it is a plasma discharge processing device that can efficiently process materials, it can be used for high-speed processing and large-area processing, and various plasma processing methods, including various methods used in the semiconductor manufacturing process, can be inlined and speeded up. Can be effectively used to realize As a result, the processing time can be shortened and the cost can be reduced, and it can be applied to various uses that were impossible or difficult in the past.

[Brief description of drawings]

FIG. 1 is a schematic device diagram illustrating an example of a discharge plasma processing device of the present invention.

[Explanation of symbols]

1 power supply (high voltage pulse power supply) 2-3 roll electrodes 4 discharge space 5 Processing gas supply nozzle 6 gas exhaust nozzle 7,7 'solid dielectric 10 Base material to be treated

Claims (7)

[Claims] 1. An apparatus for treating a substrate with glow discharge plasma generated by applying an electric field between a pair of roll electrodes whose surfaces are coated with a solid dielectric, wherein the roll electrodes are rotated. Introduce processing gas in between,
A discharge plasma processing apparatus characterized in that a base material is positioned between electrodes for processing. 2. The rotation speed of the roll electrode is 5 to 1000.
It is 0 rpm, The discharge plasma processing apparatus of Claim 1 characterized by the above-mentioned. 3. The discharge plasma according to claim 1, wherein the pair of roll electrodes have a combination of a clockwise direction and a counterclockwise direction so that they rotate in the conveying direction of the base material. Processing equipment. 4. The discharge plasma processing apparatus according to claim 1, wherein the flow rate of the processing gas is 0.1 m / sec or more. 5. The discharge plasma processing apparatus according to claim 1, further comprising a gas supply nozzle that follows the shape of the electrode. 6. The discharge plasma processing apparatus according to claim 1, further comprising a gas exhaust nozzle that follows the shape of the electrode. 7. The discharge plasma processing apparatus according to claim 1, wherein the pulse rise and / or fall time is 10 μs or less, and the electric field intensity is 10 to 1.
A discharge plasma treatment method comprising applying a pulsed electric field of 000 kV / cm and treating the substrate with glow discharge plasma generated.