JP2003166065A - Discharge plasma treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge plasma treatment apparatus which restrains the apparatus from getting larger to a minimum level even if a substrate to be treated gets bigger, and can prevent contamination caused by reactant particles during plasma treatment. <P>SOLUTION: The discharge plasma treatment apparatus applies an electric field between a pair of facing electrodes, of which at least one facing surface is coated with a solid dielectric, introduces a treatment gas inbetween the above facing electrodes, and treats a substrate to be treated, by spouting plasma onto the substrate arranged out of a plasma generation space, from an electrode structure which generates glow discharge plasma, wherein the substrate is mounted on the upper side of the electrode structure. <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 a discharge plasma processing apparatus, and more particularly, to a discharge plasma processing apparatus in which a substrate to be processed is placed on the upper side of an electrode structure and the size of the entire apparatus is suppressed.

[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.

However, even in the atmospheric pressure plasma processing method, the object to be processed is installed between parallel plate type electrodes covered with a solid dielectric or the like, a voltage is applied between the electrodes, and the object to be processed is generated by the generated plasma. In the apparatus for treating the object, the entire object to be processed is placed in the discharge space, and the object to be processed is likely to be damaged.

As a solution to such a problem, a remote type apparatus has been proposed in which the object to be processed is not arranged in the discharge space but is disposed in the vicinity thereof and the plasma is blown from the discharge space to the object to be processed. ing. In these devices, for example, as shown in FIG. 6, a remote type device composed of opposed parallel plate type electrodes is used, a substrate to be treated is installed below the electrodes, and the substrate to be treated is conveyed. The method of processing is adopted.

In the method of FIG. 6, an electric field is applied from the high voltage power source 1 to the electrodes 2 and 3, and a processing gas is introduced between the electrodes from the gas supply device 5 to generate plasma, and the electrodes conveyed by the roller conveyor 11 Substrate 10 to be treated located on the lower side
The gas is treated by being sprayed onto the substrate, and the treated gas is recovered by the gas exhaust device 7. A remote-type electrode device using such a device has a complicated structure in the electrode part and is considerably heavy, so that the support 1 for lifting the electrode part to the upper part is used.
There is a problem that a structure consisting of 5 and the pedestal 16 is required, and when the substrate to be treated becomes large, the structure needs to be further enlarged. Furthermore, on the electrode surface,
There has been a problem that reactant particles adhere to the electrode surface as the processing gas is turned into plasma, and fall onto the processing surface of the substrate during processing to contaminate the surface.

[0006]

In view of the above problems, the present invention can minimize the increase in size of the apparatus even if the size of the substrate to be processed is large, and prevents contamination by reactant particles during plasma processing. It is an object of the present invention to provide a discharge plasma processing apparatus that can prevent the above.

[0007]

As a result of intensive studies to solve the above problems, the present inventor has found that an electrode structure for generating glow discharge plasma is installed on the lower side and a substrate to be treated is installed on the upper side. As a result, they have found that the size of the apparatus can be minimized even when the size of the substrate to be processed is increased, and the contamination by the reactant particles can be prevented during the plasma processing, and the present invention has been completed.

That is, in the first aspect of the present invention, an electric field is applied between a pair of counter electrodes having at least one electrode facing surface covered with a solid dielectric, and a processing gas is introduced between the counter electrodes. A processing device for spraying plasma from an electrode structure for generating glow discharge plasma onto a substrate to be processed arranged outside a plasma generation space, wherein the substrate to be processed is installed on the upper side of the electrode structure. It is a characteristic discharge plasma processing apparatus.

A second invention of the present invention is the discharge plasma processing apparatus according to the first invention, characterized in that the electrode structure is fixed and the substrate to be processed is conveyed.

Further, a third invention of the present invention is the discharge plasma processing apparatus according to the second invention, characterized in that the substrate to be processed is carried by a non-contact carrying device.

A fourth invention of the present invention is the discharge plasma processing apparatus according to the first invention, characterized in that the substrate to be processed is fixed and the electrode structure is conveyed.

A fifth invention of the present invention is the discharge plasma processing apparatus according to the fourth invention, characterized in that the substrate to be processed is fixed by a non-contact transfer device.

In a sixth aspect of the present invention, the electric field applied to the electrode structure has a pulse rise and / or fall time of 10 μs or less and an electric field strength of 10 to 1000 kV.
The discharge plasma processing apparatus according to any one of the first to fifth inventions, wherein the discharge plasma processing apparatus has a pulse electric field of / cm.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, an electric field is applied between a pair of opposing electrodes in which at least one opposing surface of the opposing electrodes is coated with a solid dielectric, and a processing gas is introduced between the electrodes to perform glow discharge. In a discharge plasma processing apparatus that processes plasma by spraying plasma from an electrode structure that generates plasma (hereinafter, also referred to as a remote source) to a substrate to be processed that is disposed outside the discharge space, the substrate to be processed is placed on the upper side. This is a discharge plasma processing apparatus in which a remote source is installed on the lower side. The present invention will be described in detail below.

An example of the device of the present invention will be described with reference to the drawings. Figure 1
FIG. 4 is a schematic cross-sectional view of an example of an apparatus in which a remote source is fixed to a gantry 16 and the base material 10 is transported by a roller conveyor 11 on a transport gantry 12. In the method of FIG. 1, an electric field is applied from the high voltage power source 1 to the electrodes 2 and 3, and
The processing gas is introduced into the space between the electrodes to generate plasma, and the upper side of the remote source is sprayed onto the substrate 10 to be processed while being conveyed by the roller conveyor 11, and the processed gas is recovered by the gas exhaust device 7. . In such an apparatus, it is not necessary to increase the size of the entire apparatus even if the substrate to be treated has a large size, and it is possible to prevent the reactant particles from falling and re-adhering during the plasma treatment.

FIG. 2 is a schematic cross-sectional view of an example of an apparatus in which the remote source is fixed to the pedestal 16, the substrate 10 to be processed is fixed to the carrier plate 20 by the suction member 21, and the carrier plate 20 is moved. In the method of FIG. 2, the high voltage power source 1 is connected to the electrodes 2, 3
An electric field is applied to the substrate, a processing gas is introduced between the electrodes from the gas supply device 5 to generate plasma, and the upper side of the remote source is sprayed onto the substrate 10 to be processed which is transported by the transport plate 20 to process the treated gas. Is recovered by the gas exhaust device 7. Such an apparatus does not need to make the entire apparatus particularly large even if the size of the substrate to be treated is large, and it is easy to fix and remove the substrate to be treated, and to prevent reattachment of reactant particles during plasma treatment. It can be prevented.

FIG. 3 shows an example of a device in which a remote source is fixed to a pedestal 16 and the substrate 10 to be treated is held by a non-contact transfer device 22 by suction and suspended, and the non-contact transfer device 22 is moved. It is a schematic sectional view. In the method of FIG.
An electric field is applied from the high-voltage power supply 1 to the electrodes 2 and 3, and a processing gas is introduced between the electrodes from the gas supply device 5 to generate plasma,
The upper side of the remote source is sprayed onto the substrate 10 to be processed, which is transported by the non-contact transport device 22, for processing, and the treated gas is collected by the gas exhaust device 7. Such an apparatus does not need to make the entire apparatus particularly large even if the size of the substrate to be treated is large, and it is easy to fix and remove the substrate to be treated, and to prevent reattachment of reactant particles during plasma treatment. It can be prevented. The non-contact transfer device uses the suction force due to the change in static pressure of the ejector mechanism and Bernoulli mechanism and the repulsive force of the pressure chamber type air cushion mechanism to eject the air without suspending the product. However, it is a device that conveys the product without damaging or soiling it, and is commercially available as Float Chuck (trademark) from Solar Research Laboratories.

FIG. 4 is a schematic sectional view of an example of an apparatus for fixing the substrate 10 to be processed and scanning a remote source. In the method of FIG. 4, an electric field is applied from the high-voltage power supply 1 to the electrodes 2 and 3, the processing gas is introduced between the electrodes from the gas supply device 5 to generate plasma, and the remote source for blowing the plasma gas to the substrate is the support 17 A drive shaft 18 provided therebetween is provided via a support body 15 so as to be freely movable to the left and right, and is fixed to the upper side of the remote source by a suction member 21 with a fixing base 30.
The substrate 10 fixed to the substrate 10 is processed by spraying while being scanned, and the treated gas is collected by the gas exhaust device 7. Such an apparatus does not require the entire apparatus to be particularly large even if the substrate to be treated has a large size.
It is easy to remove, and it is possible to prevent the reaction particles from falling and redepositing during the plasma treatment. Note that the fixing to the fixing base 30 is not particularly limited as long as the base can be easily fixed and removed.

FIG. 5 is a schematic sectional view of an example of an apparatus for fixing the substrate 10 to be processed and scanning a remote source. In the method of FIG. 5, an electric field is applied from the high-voltage power supply 1 to the electrodes 2 and 3, a processing gas is introduced between the electrodes from the gas supply device 5 to generate plasma, and the remote source for spraying the plasma gas onto the substrate is the column 17. A drive shaft 18 provided therebetween is provided via a support body 15 so as to be freely movable to the left and right, and is sprayed onto the target substrate 10 fixed by a non-contact transfer device 22 on the upper side of the remote source while scanning. The processed gas is recovered by the gas exhaust device 7. Such an apparatus does not need to make the entire apparatus particularly large even if the size of the substrate to be treated is large, and it is easy to fix and remove the substrate to be treated, and to prevent reattachment of reactant particles during plasma treatment. It can be prevented.

Examples of the material of the electrode include those made of simple metals such as copper and aluminum, alloys such as stainless steel and brass, and intermetallic compounds. The shape of the electrode is not particularly limited as long as plasma discharge can be stabilized, but in order to avoid arc discharge due to electric field concentration,
It is preferable that the structure has a constant distance between the opposing electrodes, more preferably a shape having a parallel flat portion between the voltage application electrode and the ground electrode, and particularly preferably both electrodes are substantially flat. Is preferred.

The solid dielectric covers one or both of the facing surfaces of the electrode. At this time, the solid dielectric and the covered electrode are in close contact with each other, and the facing 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 thickness of the solid dielectric is 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 in 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.

The distance between the electrodes depends on 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.

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 pulse 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 atmospheric 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.

Under the pressure near the above 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.

The substrate to be treated by the present invention includes:
Examples thereof include plastics such as polyethylene, polypropylene, polystyrene, polycarbonate, polyethylene terephthalate, polytetrafluoroethylene, polyimide, liquid crystal polymer, epoxy resin and acrylic resin, glass, ceramic, glass for metal liquid crystal display, and the like. Examples of the shape of the substrate include a plate shape and a film shape, but are not particularly limited thereto. According to the surface treatment method of the present invention, it is possible to easily deal with the treatment of substrates having various shapes.

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, 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 ₂ 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 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 use, but for example, when forming a hydrophilic polymer film or a metal oxide thin film, the ratio of the processing gas is 0.01 to 10.
Volume% is preferred.

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 a low airtight system that prevents free outflow of gas.

According to the atmospheric pressure discharge treatment 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.

[0040]

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 electrode 2 and electrode 3, length 250 mm x height 50 mm
× A parallel plate electrode made of SUS having a thickness of 20 mm was used, and each electrode was sprayed with alumina as a solid dielectric to a thickness of 1 mm, and a remote source arranged at an interval of 2 mm was used.
It was conveyed at 0 mm / min. 6 as a base material
80 mm x 880 mm x 0.7 mm (thickness) liquid crystal display glass is fixed to a plate having suction holes,
The distance between the outlet of the remote source and the substrate was 5 mm. A mixed gas prepared by diluting 0.16% by volume of tetraethoxysilane and 16% by volume of oxygen with an argon gas was used as a processing gas, and a pulse rising speed was 5 μs between electrodes.
A pulsed electric field having a voltage of 20 kV _PP and a frequency of 10 kHz was applied. The SiO ₂ thin film was uniformly formed on the base material without dropping the reactant particles.

[0042]

EFFECTS OF THE INVENTION The discharge plasma processing apparatus of the present invention does not need to be large in size even if a large area substrate is used, and there is no redeposition of reactant particles on the surface of the substrate to be processed, so Since it is a simple processing device that can form a thin film of uniform thickness, including various methods that can be used for high-speed processing and large-area processing and are used in semiconductor manufacturing processes,
In any plasma processing method, it can be effectively used to realize in-line and high speed processing. This makes it possible to reduce processing time and cost,
It can be applied to various applications 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.

FIG. 2 is a schematic device diagram illustrating an example of a discharge plasma processing device of the present invention.

FIG. 3 is a schematic device diagram illustrating an example of a discharge plasma processing device of the present invention.

FIG. 4 is a schematic device diagram illustrating an example of a discharge plasma processing device of the present invention.

FIG. 5 is a schematic device diagram illustrating an example of a discharge plasma processing device of the present invention.

FIG. 6 is a schematic device diagram illustrating an example of a conventional discharge plasma processing device.

[Explanation of symbols]

1 power supply A few electrodes 4 discharge space 5 Processing gas supply device 7 gas exhaust system 10 Base material to be treated 11 roller conveyor 12 Transport stand 15 Support 16 mounts 17 props 18 drive shaft 20 Conveyor plate 21 Adsorption member 22 Non-contact carrier 30 fixed base

Claims (6)

[Claims] 1. An electrode structure for generating glow discharge plasma by applying an electric field between a pair of counter electrodes having at least one electrode facing surface covered with a solid dielectric and introducing a processing gas between the counter electrodes. A discharge plasma processing apparatus, which is a processing apparatus for performing processing by spraying plasma on a substrate to be processed arranged outside a plasma generation space, wherein the substrate to be processed is installed on an upper side of an electrode structure. 2. The discharge plasma processing apparatus according to claim 1, wherein the electrode structure is fixed and the substrate to be processed is conveyed. 3. The discharge plasma processing apparatus according to claim 2, wherein the substrate to be processed is carried by a non-contact carrying device. 4. The discharge plasma processing apparatus according to claim 1, wherein the substrate to be processed is fixed and the electrode structure is conveyed. 5. The discharge plasma processing apparatus according to claim 4, wherein the substrate to be processed is fixed by a non-contact transfer device. 6. The electric field applied to the electrode structure is a pulsed electric field having a pulse rise and / or fall time of 10 μs or less and an electric field strength of 10 to 1000 kV / cm. The discharge plasma processing apparatus according to item 1.