KR20070012933A - Injection type plasma treatment apparatus - Google Patents

Abstract

An injection type plasma processing apparatus is provided to reduce an unnecessary consumption of reaction gas and transfer the reaction gas to a plasma generating area quickly by making a gas injection unit of a gas supply unit connect with the plasma generating area directly. In an injection type plasma processing apparatus, a power electrode plate(20) is provided in a reaction chamber(10) when a dielectric substance(24) is formed. A ground electrode plate(40) forms a plasma(P) between the ground electrode plate and the power electrode plate(20) when an AC power is applied to the power electrode plate(20), comprises a portion of the wall of the reaction chamber(10), and includes a plurality of holes(42). A gas supply unit(50) sprays the plasma(P) outside through the holes(42) of the ground electrode plate(40) by injecting a reaction gas to the reaction chamber(10) and injects the reaction gas to a plasma generating area(PA) directly by placing a gas injection unit(52) on the plasma generating area(PA) between the power electrode plate(20) and the ground electrode plate(40).

Description

Injection Plasma Treatment System {INJECTION TYPE PLASMA TREATMENT APPARATUS}

1 is a schematic diagram schematically showing a plasma processing apparatus according to the prior art.

2 is a schematic diagram schematically showing a plasma processing apparatus according to an embodiment of the present invention.

3 is a diagram for defining factors defining processing characteristics of a plasma processing apparatus according to the present invention;

Figure 4 is a schematic diagram shown to explain the correlation between the gap between the electrode and the hole diameter in the plasma processing apparatus according to the present invention.

5 is a graph for explaining the correlation between the gap between the electrode and the hole diameter in the plasma processing apparatus according to the present invention.

Figure 6 is a schematic diagram showing a plasma processing apparatus according to the present invention the secondary discharge effect occurs in the vicinity of the ground electrode plate.

7 is a photograph photographing secondary discharges formed in the vicinity of the ground electrode plate under various conditions.

8 is a view showing the shape of the ground electrode plate designed for the diffusion injection of the plasma.

9 is a graph for showing the reaction gas consumption of the plasma processing apparatus according to the present invention as compared to the conventional plasma processing apparatus.

10 is a schematic view for explaining a plasma processing apparatus according to another embodiment of the present invention.

<Code Description of Main Parts of Drawing>

10: reaction chamber 20: power electrode plate

22: conductor 24: dielectric

40: ground electrode plate 42: hole

50: gas supply unit 52: gas injection unit

54: power source T: object to be treated

P: plasma PA: plasma generating region

The present invention relates to an injection type plasma processing apparatus and method, and more particularly, to plasma treatment objects having various areas, various sizes, and various shapes by using dielectric film discharge (DBD) at atmospheric pressure. The present invention relates to an injection type plasma processing apparatus which is capable of processing, but which reactant gas can be supplied to the plasma generating region quickly and without large loss.

In general, pulsed corona discharge and dielectric film discharge are known as techniques for generating plasma at atmospheric pressure, that is, at atmospheric pressure. Pulsed corona discharge is a technique for generating plasma using a high voltage pulse power supply, and dielectric film discharge forms a dielectric on at least one of the two electrodes and applies a power source having a frequency of several tens of Hz to several MHz to the two electrodes. It is a technique to generate.

In atmospheric pressure discharges, increasing the barometric pressure of the system entails a significant reduction in the mean free path and thus requires an extreme of electrical discharge conditions. Therefore, the existing atmospheric pressure discharge system requires a very strong electric field, which causes problems such as enlargement of the generated power source. Therefore, there is a need for a technique for generating plasma at an easy and inexpensive and large volume at atmospheric pressure.

As an atmospheric pressure plasma treatment technique using a DBD discharge technique, U.S. Patent No. 5,124,173 to Uchiyama et al. Discloses a method of hydrophilic treatment of a surface by placing a target object between flat plate electrodes and generating a dielectric film discharge at atmospheric pressure using an inert gas. In addition, US Patent No. 5,414,324 to Roth et al. Discloses a technique for improving a discharge state by changing conditions such as gas composition and interelectrode spacing for forming atmospheric pressure plasma, and US Patent No. 6,429,400. Atmospheric pressure plasma apparatus using a tube-shaped electrode is disclosed in the present invention, Korean Patent No. 0365898 discloses a reaction gas such as He, Ar, etc. in the chamber and the reaction gas between the two electrodes between the dielectric plate Treating the object to be treated between the two electrodes with a plasma formed between the two electrodes by flowing therebetween. Techniques are disclosed.

Referring to FIG. 1, an example of the related art as described above, the conventional plasma processing apparatus 100 includes two electrodes 120 and 140 formed with dielectrics 122 and 142 in the reaction chamber 110. Plasma is disposed facing each other, the plasma generated by the discharge gas generated between the two electrodes (120, 140) and the reaction chamber 110 introduced by the reaction gas flowing between the two electrodes to be disposed between the two electrodes (T) Could do the processing.

However, in the conventional plasma processing apparatus as described above, since the object to be treated is disposed between the two electrodes which cause discharge, there is a limit to the treatment of the object having a large thickness, a complex shape in three dimensions, or a large area. there was. In addition, in the conventional plasma processing apparatus, it is difficult to space the gap between two electrodes by several mm or more, and the glow is not uniformly discharged, and a large amount of microarc streamers are generated between the two electrodes to damage the object to be treated. There was great concern. In addition, the conventional plasma processing apparatus has a large overall volume of the chamber compared to the plasma generating region, and a considerable amount of the reaction gas introduced into the chamber does not contribute to the generation of plasma. There was a problem.

  Accordingly, an object of the present invention is to spray plasma formed by dielectric barrier discharge (DBD) at a normal pressure (ie, atmospheric pressure) toward a treatment object, and have various areas, various sizes, and various shapes. It is possible to provide a spraying plasma treatment apparatus capable of treating an object to be treated without damage by a microarc streamer, and supplying a reaction gas to a plasma generating region quickly and without large loss.

In addition, another object of the present invention is to provide an injection type plasma processing apparatus having a structure in which all electrodes defining a plasma generating region are exposed to the outside of the reaction chamber to facilitate cooling of the electrodes.

In order to achieve the above object, the present invention provides a spray type plasma processing apparatus for generating a plasma in the reaction chamber, and spraying the generated plasma toward the object to be treated, wherein the plasma processing apparatus is the reaction with a dielectric formed A ground electrode is formed between the power electrode plate provided in the chamber and the power electrode plate when AC power is applied to the power electrode plate, forming a part of a wall of the reaction chamber, and forming a plurality of holes. Injecting a reaction gas into the reaction chamber into the plate and the plasma in the reaction chamber to the outside through the holes of the ground electrode plate, the gas injection portion provided in the plasma generating region between the power electrode plate and the ground electrode plate And a gas supply unit for directly injecting a reaction gas toward the plasma generation region. do.

Here, the gas injection unit is preferably provided to be adjacent to the power electrode plate toward the lower plasma generation region. In another embodiment, the gas injection unit may be provided on the side wall of the reaction chamber to face the side plasma generation region.

In addition, it is preferable that the power electrode plate is provided on the upper wall of the reaction chamber and the ground electrode plate is provided on the reaction chamber so that the plasma generating region is formed between the upper wall and the lower wall. In addition, it is preferable that the power electrode plate can be cooled by air cooling or any cooling means while being exposed to the outside on the upper wall.

In addition, the diameters of the holes are set within 5 times, more preferably, 3 to 5 times the distance between the power electrode plate and the ground electrode plate, and the distance between the ground electrode plate and the object to be treated is 25 times the diameter of the holes. It is preferably set within 15 times, more preferably 15 to 25 times, the distance between the ground electrode plate and the power electrode plate is set to 0.03mm ~ 45mm and the diameter of the holes is set to 0.01mm ~ 9mm. In addition, the holes preferably extend in diameter from the reaction chamber side toward the object to be treated, which enables the plasma sprayed through the holes of the ground electrode to be widely spread in a uniform distribution on the object to be treated. .

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a schematic diagram schematically showing an injection plasma processing apparatus 1 according to an embodiment of the present invention.

As shown in FIG. 2, the plasma processing apparatus 1 according to the present embodiment includes a reaction chamber 10, a power electrode plate 20 and a ground electrode plate 40 provided to the reaction chamber 10. And a gas supply unit 50 for supplying a reaction gas into the reaction chamber 10.

In the present embodiment, the reaction chamber 10 is installed on the frame 12 and the frame 12 constituting part of the side wall, the upper wall and / or the lower wall, and the power electrode plate 20 and the ground electrode plate 40. ), Which forms one space in which plasma is generated.

The power electrode plate 20 is an electrode that is activated by receiving power of a high voltage having a frequency of about 1 KHz to 90 MHz and a voltage of 0.1 kV to 900 kV from an AC power supply 60 outside the reaction chamber 10. It is made of a dielectric material 24 formed on the bottom. At this time, the dielectric material 24 may be an oxide-based ceramic such as MgO, Al ₂ O ₃ , Ti _{O 2} , Pb (Zr, Ti) O ₃ , Si ₃ N ₄ , PZT, or other zirconia titanate (PZT). Polymer-based resins such as PTFE (polytetrafluoroethylene), Teflon, ABS (Acrylonitrile Butadiene Styrene), PEEK (Poly Ether Ether Ketone), PC (Poly Carbonate), and PVC (Poly vinyl Chloride) may be used. At this time, the power electrode plate 20 according to the present embodiment constitutes a part of the upper wall of the reaction chamber 10 to help the cooling of the power electrode plate 20 is easily performed as described in detail below. The generating area PA is made to be substantially the same space as the reaction chamber 10 to prevent unnecessary consumption of the reactant gas and to supply a fast reactant gas to the plasma area.

In the present embodiment, the ground electrode plate 40 constitutes the lower wall of the reaction chamber 10 and is predetermined from the dielectric electrode 24 on the power electrode plate 20, more specifically, the power electrode plate 20. The plasma generation area PA is formed between the power electrode plates 20 while being spaced apart from each other. A plurality of holes 42 are formed in the ground electrode plate 40 to face the processing object T disposed below the ground electrode plate 40. The plurality of holes 42 may be treated with the aid of the gas supply unit 50, which is described below, in the plasma generated in the plasma generating area PA between the ground electrode plate 40 and the power electrode plate 20. To be sprayed). In addition, the ground electrode plate 40 is made of a precious metal such as platinum (Pt), tungsten (W), silver (Ag), which emits a lot of secondary electrons, or the above-described precious metal is coated on at least an inner surface thereof. It is preferably formed, which facilitates easier discharge between the ground electrode plate 40 and the power electrode plate 20 under atmospheric pressure.

On the other hand, the gas supply unit 50 supplies the reaction gas into the reaction chamber 10 through the gas injection unit 52 formed on the side wall of the reaction chamber 10. The reaction gas may vary depending on the type of the treatment object T or the surface treatment method of the treatment object. For example, the surface treatment method for the treatment object may include surface modification, Si etching, photoresist etching, Depending on either sterilization or film deposition, N ₂ , O ₂ , Ar He, CO ₂ , CO, H ₂ , NH ₃ , CF ₄ , CH ₄ , C ₂ H ₆ , air or water vapor Can be used.

The reaction gas supplied in the reaction chamber 10 is injected to the outside through the plurality of holes 42 formed in the ground electrode 40 through the plasma generation region PA in the reaction chamber 10, and in this process, the plasma is generated. The plasma P generated in the area PA is also injected toward the object T outside the reaction chamber 10. In this case, the gas injection unit 52 is formed between the upper wall of the reaction chamber 10 in which the power electrode plate 20 is formed and the lower wall of the reaction chamber 10 in which the ground electrode plate 40 is formed. The reaction gas supplied into the reaction chamber 10 can inject plasma P present in the plasma generation region PA to the outside without loss and quickly. In FIG. 2, the gas injection unit 52 is formed on the side wall of the reaction chamber 10 so as to be directly connected to the plasma generation area PA of the reaction chamber 10. It may be formed on the upper wall of the reaction chamber 10 adjacent to the power electrode plate 20. Even in this case, the gas injection unit 52 is directly through the plasma generation region below.

In addition, since the power electrode plate 20 is exposed to the outside on the upper wall of the reaction chamber 10, the power electrode plate 20 can be easily cooled by external air or any cooling means. It contributes to reducing overheating of the power electrode plate 20 by the electrical resistance heat generated accordingly.

FIG. 3 is a diagram for defining factors defining processing characteristics of the plasma processing apparatus according to the present invention. Referring to FIG. 3, "a" represents a diameter of a hole formed in the ground electrode plate 40 (hereinafter, referred to as "hole diameter"). 'B' indicates a gap between the power electrode plate 20 and the ground electrode plate 40 (hereinafter, referred to as an 'inter electrode gap'), and “D” indicates a ground electrode plate 40. ) And the processing object T (hereinafter referred to as 'processing interval'). The correlation between the above factors will be described with reference to FIGS. 4 to 7.

4 and 5 are diagrams for explaining the effect of the hole diameter (a) and the distance (b) between the electrode on the object (T) when the plasma processing apparatus of the present invention is driven. As shown in Fig. 4 and 5, the plasma processing apparatus according to the present invention, when the hole diameter (a) is larger than 5 times the inter-electrode spacing (b), that is, when a> 5b, fine generated during plasma generation The arc streamer S passes through the ground electrode plate 40 and affects the processing object T below. In this case, the processing object T may be damaged by the microarc streamer S. FIG. In contrast, when the hole diameter (a) is 5 times or less of the inter-electrode spacing (b), that is, when a≤5b, the fine arc streamer (S) generated during plasma generation hardly exceeds the ground electrode plate (40). Therefore, the damage caused by the generation of the microarc streamer S does not occur in the object to be processed T disposed below the ground electrode plate 40. This is because the plasma processing apparatus according to the present invention is generated between the electrode plates (20, 40) by adjusting the hole diameter (a) and the inter-electrode spacing (b), which can damage the object (T) S) can be limited. Particularly, the hole diameter (a) is set within 5 times, more preferably, 3 to 5 times the distance (b) between the electrodes, and the hole diameter (a) is 0.01 to 9 mm. , When the electrode distance (b) is set to 0.03 ~ 45mm, it was confirmed through the experiment that the microarc streamer (S) does not have any effect on the object (T).

As described above, the plasma processing apparatus according to the present invention prevents the microarc streamer S from damaging the object T by adjusting the hole diameter a and the distance between the electrodes b. The treatment object T in which the plasma P formed by the strong electric field between the plate 10 and the ground electrode plate 40 is adjacent to the ground electrode plate 40 through the hole 42 of the ground electrode plate 40. Since the reactive species, ions, electrons, etc., generated at the time of plasma formation, can be effectively used for surface modification, cleaning, etching, etc. of the object to be treated (T).

6 is a schematic diagram showing the secondary discharge effect occurring under a predetermined hole diameter (a) and the processing interval (D) in the plasma processing apparatus of the present invention. As shown in Fig. 6, the processing interval D, i.e., the distance D between the ground electrode plate 40 and the object T, is approximately 25 times the hole diameter a of the ground electrode plate 40. Within a period of time, more preferably, 15 to 25 times, a secondary discharge effect is induced directly below the ground electrode plate 40, which is caused by plasma being injected through the holes 42 of the ground electrode plate 40. By diffusing P) in the width direction, it is possible to increase the plasma treatment efficiency for the treatment object (T). FIG. 7 is a photographic view of photographing plasma discharge while varying the interval between the object T and the ground electrode plate 40, that is, the processing interval D, with respect to the determined hole diameter a. Referring to FIG. 4, it can be seen that the plasma diffusion effect is maximized as the processing interval D becomes smaller, that is, the closer the ground electrode plate and the processing target are.

In addition to the above-described secondary discharge, the shape of the hole 42 of the ground electrode plate 40 is designed as shown in FIG. 8 to further increase the diffusion effect of the plasma and thereby to perform a more uniform plasma treatment on the object to be treated. It is possible to do That is, as shown in FIGS. 8A and 8B, the hole 42 of the ground electrode plate 40 is designed such that its diameter is extended toward the object to be treated. Can be further increased.

As described above, the plasma processing apparatus according to the present invention can easily process a plasma processing object having various areas, various sizes, and various shapes without damage by a microarc streamer, etc. By forming a ground electrode plate 40 having a plurality of holes 42 in the lower wall of the reaction chamber 10, and the reaction gas to spray the plasma (P) through the plurality of holes 42 The object to be treated can be efficiently processed without consuming excessive reaction gas. In particular, the plasma processing apparatus 1 is provided with the gas injection unit 52 of the gas supply unit 50 in the plasma generation area PA, so that the reaction gas injected into the reaction chamber 10 is almost lost. It is used in the plasma injection, it is possible to further reduce the consumption of the reaction gas.

FIG. 9 is a graph comparing reaction gas consumption of a plasma processing apparatus (comparative example) of a conventionally known injection tube method with a plasma processing apparatus according to an embodiment of the present invention. It is a figure which showed the flow volume of this as a graph. Referring to FIG. 9, the plasma processing apparatus 1 of the present embodiment shows that, compared with the comparative example, only the reaction gas having a much lower flow rate is used during the same plasma processing, which is the plasma processing apparatus 1 of the present embodiment. This means that the plasma can be generated and injected with a smaller amount of reaction gas than the conventional plasma processing apparatus.

10 is a view showing a plasma processing apparatus according to a modified embodiment of the present invention. As shown in FIG. 10, in the plasma processing apparatus of this embodiment, the power electrode plate 20 is formed inside the reaction chamber 10, and the reaction chamber 10 supplies gas to the power electrode plate 20. The plasma is partitioned into the area GA and the plasma shielding area PA, and the reaction gas flows into the plasma generation area through the flow path 17 formed between the power electrode plate 20 and the side wall of the reaction chamber 10. Represents a processing device.

In FIG. 2 and FIG. 10, one gas injection unit 52 is shown connected to the reaction chamber 10, but this is only one embodiment and the plurality of gas injection units 52 is connected to the reaction chamber 10. Of course, it is also possible to connect. In addition, in the foregoing embodiments, although the holes formed in the ground electrode plate 40 have been described as being circular, the above-described holes may be formed in a triangular, square or slit shape as well as circular.

As described above, the plasma processing apparatus according to the present invention has a structure in which a treatment object is disposed under a ground electrode plate having a plurality of holes, and has a thick, three-dimensional complex shape, or a large area. The object to be treated can be plasma-processed easily and with high processing efficiency, and the gas injection unit of the gas supply unit is directly connected to the plasma generating region, thereby reducing unnecessary consumption of the reactant gas and rapidly moving the reaction gas to the plasma generating region. Has the effect of sending.

In addition, the present invention has an effect that can greatly reduce the overheating of the power electrode plate by the heat of electrical resistance by exposing the electrode plate, in particular the power electrode plate to the outside of the reaction chamber.

In addition, the present invention has the effect of controlling the microarc streamer that can damage the processing object through the proper design of the diameter of the holes formed in the ground electrode plate and the electrode spacing between the ground electrode plate and the power electrode plate. .

In addition, the present invention can increase the diffusion effect of the plasma through the proper design of the diameter of the holes formed in the ground electrode plate and the processing interval between the ground electrode plate and the object and / or the shape of the hole to more uniform and wider plasma The effect is that it can be processed.

Claims (11)

An injection type plasma processing apparatus which generates a plasma in a reaction chamber and injects the generated plasma toward an object to be treated. A power electrode plate provided in the reaction chamber with a dielectric formed therein; A ground electrode plate which forms a plasma between the power electrode plate when AC power is applied to the power electrode plate, constitutes a part of a wall of the reaction chamber, and has a plurality of holes; Injecting a reaction gas into the reaction chamber to inject the plasma in the reaction chamber to the outside through the holes of the ground electrode plate, the gas injection portion provided in the plasma generating region between the power electrode plate and the ground electrode plate, the plasma A gas supply unit for directly injecting the reaction gas toward the generation region; Spraying plasma processing apparatus comprising a. The injection type plasma processing apparatus of claim 1, wherein the gas injection unit is disposed to face the plasma generation region below the power injection plate. The injection type plasma processing apparatus of claim 1, wherein the gas injection unit is disposed on a sidewall of the reaction chamber and directed toward a side plasma generation region. The injection plasma processing apparatus of claim 1, wherein the power electrode plate is provided on an upper wall of the reaction chamber, and the ground electrode plate is provided on the reaction chamber, and a plasma generation region is formed between the upper wall and the lower wall. The injection plasma processing apparatus of claim 1, wherein the power electrode plate may be cooled by air cooling or any cooling means while being exposed to the outside on the upper wall. The spraying plasma processing apparatus of claim 1, wherein a diameter of the holes is set within 5 times a distance between the power electrode plate and the ground electrode plate. The spraying plasma processing apparatus of claim 1, wherein a distance between the ground electrode plate and the processing target is set within 25 times the diameter of the holes. The spraying plasma processing apparatus of claim 1, wherein a distance between the ground electrode plate and the power electrode plate is set to 0.03 mm to 45 mm. The spraying plasma processing apparatus of claim 1, wherein the holes have a diameter of about 0.01 mm to about 9 mm. The injection plasma processing apparatus of claim 1, wherein the holes are arranged in a triangular, square, circular, or slit form on the ground electrode plate. The injection plasma processing apparatus according to any one of claims 1 to 10, wherein the holes extend in diameter from the reaction chamber side toward the object to be treated.

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