Plasma processing equipment

Abstract

The objective of the present invention is to provide a plasma processing apparatus that can achieve further improvements in plasma processing efficiency compared to conventional plasma processing apparatuses that irradiate an object with plasma-like gas. [Solution] The plasma irradiation apparatus 100 of the present invention is a plasma processing apparatus 100 for plasma processing of an object T, and comprises a first plasma generation unit 10 for plasmaizing a first gas G1, and a second plasma generation unit 20 for plasmaizing a second gas G2 different from the first gas G1, and a mixed plasma P1 generated in the first plasma generation unit 10 and a second plasma P2 generated in the second plasma generation unit 20 are mixed together to form a mixed plasma P C It is configured to irradiate the target object T.

Description

Technical Field

[0001] The present invention relates to a plasma processing apparatus for subjecting an object to plasma processing, and more particularly to an apparatus for performing plasma processing by irradiating the object with mixed plasma in which a plurality of plasmas generated from different gases are mixed respectively.

Background Art

[0002] In recent years, in plasma processing, it is known that by mixing a small amount of another type of gas into the gas that generates plasma as shown in FIG. 4, the effects of surface treatment and sterilization treatment in plasma processing are improved.

Summary of the Invention

Problems to be Solved by the Invention

[0003] However, in plasma processing using a gas obtained by plasmaizing a gas in which a small amount of another type of gas is mixed into a conventional plasma-generating gas, the plasma processing efficiency may still be insufficient.

[0004] An object of the present invention is to obtain a plasma processing apparatus that can further improve the plasma processing efficiency with respect to a plasma processing apparatus that irradiates an object with a gas obtained by plasmaizing a mixed gas in which a small amount of another type of gas is mixed into a conventional plasma-generating gas.

Means for Solving the Problems

[0005] The present invention provides the following items. (Item 1) A plasma processing apparatus for subjecting an object to plasma processing, wherein the plasma processing apparatus comprises a first plasma generation unit for plasmaizing a first gas and a second plasma generation unit for plasmaizing a second gas different from the first gas. A plasma processing apparatus configured to irradiate an object with a mixed plasma obtained by mixing a first plasma generated in the first plasma generation unit and a second plasma generated in the second plasma generation unit.

[0006] (Item 2) The plasma processing apparatus according to item 1, further comprising a mixed plasma generation unit that mixes the first plasma generated in the first plasma generation unit and the second plasma generated in the second plasma generation unit without exposing them to the external atmosphere.

[0007] (Item 3) The plasma apparatus according to item 1, wherein the first gas and the second gas are carbon dioxide, argon, helium, water vapor, nitrogen (including nitrogen zincide), carbon tetrafluoride, sulfur hexafluoride, oxygen, air, or a mixture thereof.

[0008] (Item 4) The plasma processing apparatus further comprises a third gas supply unit for supplying a third gas or a third plasma generation unit for plasmaizing the third gas, The plasma processing apparatus according to item 1, configured to mix the third gas supplied from the third gas supply unit, or the third plasma generated in the third plasma generation unit, with the mixed plasma obtained by mixing the first plasma generated in the first plasma generation unit and the second plasma generated in the second plasma generation unit.

[0009] (Item 5) The plasma treatment apparatus described in any one of items 1 to 4, wherein the plasma treatment is atmospheric pressure plasma treatment.

[0010] (Item 6) A plasma treatment method for treating an object with plasma, A plasma treatment method comprising discharging the mixed plasma onto the treatment surface of an object using the plasma treatment apparatus described in item 1. [Effects of the Invention]

[0011] According to the present invention, it is possible to obtain a plasma processing apparatus that can further improve the plasma processing efficiency with respect to a conventional plasma processing apparatus that irradiates an object with a plasma of a gas.

Brief Description of the Drawings

[0012] [Figure 1] The figure which shows the plasma processing apparatus 100 by Embodiment 1 of this invention. [Figure 2] The figure which shows the plasma processing apparatus 120 by the modification of Embodiment 1 of this invention. [Figure 3] The figure which shows the modification of the mixed plasma generation part of the plasma processing apparatus 120 of this invention. [Figure 4] The figure which shows the conventional plasma processing apparatus. [Figure 5] The figure which shows the experimental result of Test 1 of the hydrophilicity test. [Figure 6] The figure which shows the experimental result of Test 2 of the hydrophilicity test.

Modes for Carrying Out the Invention

[0013] Hereinafter, the present invention will be described. It should be understood that the terms used in this specification are used in the meanings commonly used in the art unless otherwise specified. Therefore, unless otherwise defined, all technical terms and scientific and technical terms used in this specification have the same meanings as commonly understood by those skilled in the art to which the present invention pertains. In case of contradiction, this specification (including the definitions) shall prevail.

[0014] In this specification, "about" means within the range of ±10% of the following number.

[0015] An object of the present invention is to obtain a plasma processing apparatus that can further improve the plasma processing efficiency with respect to a conventional plasma processing apparatus that irradiates an object with a plasma of a gas. A plasma processing apparatus for subjecting a fluid to plasma processing, The plasma processing apparatus has a first plasma generation unit that generates plasma of a first gas and a second plasma generation unit that generates plasma of a second gas different from the first gas, and solves the above problems by providing a plasma processing apparatus configured to irradiate an object with a mixed plasma obtained by mixing the first plasma generated by the first plasma generation unit and the second plasma generated by the second plasma generation unit.

[0016] Therefore, the plasma processing apparatus of the present invention is not particularly limited as long as it has a first plasma generation unit that generates plasma of a first gas and a second generation unit that generates plasma of a second gas different from the first gas, and is configured to mix the first plasma generated from the first plasma generation unit and the second plasma generated from the second plasma generation unit to generate a mixed plasma.

[0017] (Object) The object can be arbitrary depending on the required plasma processing. For example, it may be an artificial object such as metal, resin (including functional plastics, etc.), ceramic, or it may be a human body such as skin.

[0018] (First gas and second gas) For example, the first gas can be any gas as long as it can be made into plasma. For example, it can be any one of carbon dioxide, argon, helium, water vapor, nitrogen (including zinc nitride), carbon tetrafluoride, sulfur hexafluoride, oxygen, air, or a mixed gas thereof. It may also contain volatile compounds, mists, and fine particles. For example, the mixed gas is oxygen and about 1% by volume of hydrogen, but the present invention is not limited thereto.

[0019] The second gas may be a gas different from the first gas.

[0020] By selecting various gases for both the first and second gases, it becomes possible to perform a variety of treatments such as hydrophilic treatment, sterilization treatment, therapeutic treatment, and deodorization treatment.

[0021] For example, when the first and second gases are carbon dioxide and oxygen, or hydrogen and nitrogen, a hydrophilic treatment effect is obtained. When oxygen and nitrogen are used, a wound healing effect is obtained through NO radicals. When oxygen and hydrogen are used, sterilization and adhesion improvement effects are obtained through OH radicals.

[0022] In this embodiment, the case in which two types of gases, a first gas and a second gas, are used is described, but the plasma processing apparatus of the present invention is not limited to this. For example, plasma generated from three or more types of gases may be mixed.

[0023] Furthermore, when mixing three or more gases, it is not necessary to plasmaize all of them individually. For example, the third gas may be mixed directly with the first and second plasmas without being plasmaized.

[0024] In other words, the system may include a third gas supply unit for supplying a third gas, or a third plasma generation unit for converting the third gas into plasma, and when mixing the first plasma and the second plasma, the third gas or the third plasma may be mixed in a similar manner to generate a mixed plasma.

[0025] (First plasma generation unit and second plasma generation unit) The first plasma generation unit and the second plasma generation unit can be any known plasma generation method. For example, they may be electrode-based discharges such as arc discharge, glow discharge, barrier discharge, and corona discharge, electrode-less induction discharge, combustion, or gas discharge, solid discharge, or liquid discharge by laser irradiation. In one embodiment, the first plasma generation unit and the second plasma generation unit employ an electrode discharge method.

[0026] Furthermore, the form of the mixed plasma can be arbitrary, as long as it is possible to mix the first plasma generated in the first plasma generation unit and the second plasma generated in the second plasma generation unit to generate a mixed plasma.

[0027] For example, the system may be configured to generate a mixed plasma by injecting a first plasma from a first plasma generation unit into the external atmosphere, and simultaneously injecting a second plasma from a second plasma generation unit into the external atmosphere, and mixing the first and second plasmas in the external atmosphere. Alternatively, the system may be configured to generate a mixed plasma by mixing the first plasma generated from the first plasma generation unit and the second plasma generated from the second plasma generation unit without exposing them to the external atmosphere.

[0028] Specifically, the system is configured to include a mixed plasma generator equipped with a Y-shaped connecting pipe, with one end of the Y-shaped connecting pipe connected to the ejection port of the first plasma generation unit and the other end of the connecting pipe connected to the ejection port of the second plasma generation unit.

[0029] Embodiments of the present invention will be described below with reference to the drawings.

[0030] (Embodiment 1) Figure 1 shows a plasma processing apparatus 100 according to Embodiment 1 of the present invention.

[0031] This plasma processing apparatus 100 is an atmospheric pressure plasma apparatus comprising a first plasma generation unit 10 for generating plasma from a first gas G1 supplied from an external source, and a second plasma generation unit 20 for generating plasma from a second gas G2 supplied from an external source. The first plasma generation unit 10 and the second plasma generation unit 20 are the same plasma generation means, but they may be different plasma generation means.

[0032] The first plasma generation unit 10 is equipped with a discharge electrode type plasma generation means, and comprises a housing including two electrodes (not shown), a voltage application means for discharging between these electrodes, a supply pipe for supplying gas between the two electrodes, and a nozzle 11 for ejecting the generated plasma. The second plasma generation unit 20 has a similar structure to the first plasma generation unit 10, and comprises a housing including two electrodes (not shown), a voltage application means for discharging between these electrodes, a supply pipe for supplying gas between the two electrodes, and a nozzle 21 for irradiating with the generated plasma.

[0033] Then, the first plasma P1 irradiated from the nozzle 11 of the first plasma generation unit 10 and the second plasma P2 irradiated from the nozzle 21 of the second plasma generation unit 20 are mixed before being irradiated onto the object, and mixed plasma P C The nozzle 11 of the first plasma generation unit 10 and the nozzle 21 of the second plasma generation unit 20 are arranged so that plasma is generated. Here, regarding the plasma generation conditions of the first plasma generation unit 10 and the second plasma generation unit 20, the inventors have determined from experiments that the supply amount of at least the first gas G1 and / or the second gas G2 is about 1 to about 5 L / min, the frequency is DC to about 2.45 GHz, and the applied voltage is about 0.5 to 10 kV.

[0034] As shown in Figure 1, mixed plasma P is generated when the first plasma P1 generated from the first gas G1 in the first plasma generation unit 10 and the second plasma generated from the second gas G2 in the second plasma generation unit 20 are mixed. C Plasma treatment is performed by irradiating the target object T with plasma.

[0035] Mixed plasma P generated by the plasma processing apparatus of the present invention C Unlike conventional plasma processing devices (see, for example, Figure 4), this is a mixed gas plasma P generated from a mixed gas obtained by mixing a first gas G1 and a second gas G2. 1+2A different type of active species is generated, enabling more efficient plasma processing than with conventional plasma processing equipment. The applicant has for the first time discovered that mixed plasma, which is a mixture of different plasmas rather than a plasma of mixed gases, has a significant effect on plasma processing.

[0036] (Modified version of Embodiment 1) Figure 2 shows a plasma processing apparatus 120 according to a modified embodiment 1 of the present invention.

[0037] The plasma processing apparatus 120 shown in Figure 2 differs from the plasma processing apparatus 100 shown in Figure 1 in that the plasma processing apparatus 120 is equipped with a mixed plasma generation unit 30.

[0038] The mixed plasma generation unit 30 is an adapter equipped with a Y-shaped connecting pipe. One end of the Y-shaped connecting pipe of the mixed plasma unit 30 is connected to the nozzle 11 of the first plasma generation unit 10, the other end of the Y-shaped connecting pipe is connected to the nozzle 21 of the second plasma generation unit 20, and the third end of the Y-shaped connecting pipe is connected to the mixed plasma P C It will become the nozzle.

[0039] By providing the mixed plasma generation unit 30 in this way, it becomes possible to mix the first plasma P1 and the second plasma P2 without exposing them to an external atmosphere such as air, and to generate the mixed plasma P2 more efficiently. C This makes it possible to generate [the plasma]. In the embodiment shown in Figure 2, the nozzle 11 of the first plasma generation unit 10, the nozzle 21 of the second plasma generation unit 20, and the third plasma generation unit 30 are formed separately, but they may also be formed as a single unit.

[0040] Furthermore, the plasma processing apparatus 100 and 120 of the present invention may be equipped with a device for diagnosing the plasma state. For example, an emission spectrometer or an absorbance spectrometer may be used as a device for diagnosing the plasma state. (Mixed plasma generation section 30) In the embodiment shown in Figure 2, the mixed plasma generation unit 30 had a Y-shaped connecting pipe configuration, but the present invention is not limited to this. Figure 3 shows various forms of the mixed plasma generation unit 30. In Figure 3, if there are two arrows, the right side indicates the first plasma and the left side indicates the second plasma. If there are three arrows (except for (7)), the left side indicates the second plasma, the center indicates the first plasma, and the right side indicates the third gas (including the third plasma). It is also possible to change these arrangements.

[0041] Figure 3(1) shows a Y-shaped connecting tube as shown in Figure 2. Figure 3(2) shows a configuration in which the first plasma is supplied through a straight tube and the second plasma joins it from the side. Figure 3(3) shows a configuration in which the first and second plasmas are supplied through two parallel, substantially straight tubes and join them in a tube of approximately the same size as one substantially straight tube. Figure 3(4) shows a configuration in which the first and second plasmas are supplied through parallel, substantially straight tubes and one substantially straight tube joins the other substantially straight tube. Figure 3(5) shows a configuration in which the first and second plasmas are supplied through parallel, substantially straight tubes and join in a tube of approximately the same diameter as the two substantially straight tubes. Figure 3(6) shows a configuration that provides a buffer for efficiently mixing the first and second plasmas. Figure 3(7) shows a configuration in which a buffer is provided to efficiently mix the first plasma and the second plasma, and the buffer is configured to create a cyclone-like flow of the second gas. Figure 3(8) shows a configuration in which the pipe supplied with the first plasma is large and the pipe supplied with the second plasma is small. Figure 3(9) shows a configuration in which the pipe supplied with the first plasma is large and the pipes supplied with the second plasma and the third gas (including the third plasma) are small. Figure 3(10) shows a configuration in which the pipe supplied with the first plasma is large and the confluence point of the second plasma joining the first plasma and the confluence point of the third gas (including the third plasma) joining the first plasma are located at different positions.

[0042] (Evaluation of hydrophilicity (adhesion strength)) (Test 1) The plasma treatment (hydrophilic treatment) was evaluated under the following plasma treatment conditions. The plasma treatment conditions were: supply rate of first and second gases of 3 L / min, frequency of 16 kHz, applied voltage of 9 kV, and the target object was an aluminum plate measuring 20 mm wide x 70 mm long. The irradiation distance between the plasma irradiation area and the target object (h1 and h2 in Figure 1) was 11 mm each.

[0043] Test condition 1 is shown in Table 1.

[0044] [Table 1] The hydrophilicity treatment was evaluated by measuring the contact angle α of a water droplet (approximately 1 μL) dropped onto the plasma-treated surface of the object, as shown in Figure 5(a). A lower contact angle indicates improved hydrophilicity.

[0045] The experimental results are shown in Figure 5(b). As can be seen in Figure 5(b), Comparative Example 1, which did not undergo plasma treatment, had the worst hydrophilicity with an average contact angle of 89°. When carbon dioxide was used as the gas, the average contact angle was 66°, and when oxygen was used as the gas, the average contact angle was 52°. Similarly, when a mixed gas of carbon dioxide and oxygen was plasma-treated, the average contact angle was 54°. In contrast, when the plasma treatment apparatus of the present invention was used with carbon dioxide as the first gas and oxygen as the second gas, and the first and second plasmas generated were mixed to produce a mixed plasma, the contact angle decreased significantly, and the hydrophilicity was further improved, not only compared to Comparative Examples 1 to 3, but also compared to Comparative Example 4, which was treated with a mixed gas plasma.

[0046] (Test 2) The plasma treatment (hydrophilic treatment) was evaluated under the following plasma treatment conditions. The plasma treatment conditions were: supply rate of first and second gases of 3 L / min, frequency of 16 kHz, applied voltage of 9 kV, and the target object was an aluminum plate measuring 20 mm wide x 70 mm long. The irradiation treatment between the plasma irradiation area and the target object (h1 and h2 in Figure 1) was 1 mm each.

[0047] Test condition 2 is shown in Table 2.

[0048] [Table 2] The experimental results are shown in Figure 6. As can be seen in Figure 6, Comparative Example 5, which did not undergo plasma treatment, had the worst hydrophilicity with an average contact angle of 89°. When argon was used as the gas, the average contact angle was 37°, and when oxygen was used as the gas, the average contact angle was 21°. Similarly, when a mixed gas of argon and oxygen was plasma-treated, the average contact angle was 27°. In contrast, when the plasma treatment apparatus of the present invention was used with argon as the first gas and oxygen as the second gas, and the first and second plasmas generated were mixed to produce a mixed plasma, the average contact angle of 21° was significantly reduced not only compared to Comparative Examples 5 to 7, but also compared to Comparative Example 8, which was treated with a mixed gas plasma, indicating a further improvement in hydrophilicity.

[0049] The results of Test 2 showed that plasma-forming argon and oxygen separately resulted in a lower contact angle and improved hydrophilicity compared to mixing plasma-forming carbon dioxide and oxygen separately. Furthermore, it was found that shortening the irradiation distance further lowered the contact angle and improved hydrophilicity.

[0050] In this experiment, hydrophilicity was evaluated as part of the plasma treatment evaluation, but similar effects can be obtained in other plasma treatments such as sterilization by selecting the appropriate gas.

[0051] As described above, the present invention has been illustrated using preferred embodiments, but the present invention should not be construed as being limited to these embodiments. It is understood that the scope of the present invention should be interpreted solely by the claims. Those skilled in the art will understand that, based on the description of the specific preferred embodiments of the present invention and common technical knowledge, an equivalent scope can be practiced. It is understood that the documents cited herein should be incorporated as reference to this specification, just as their contents are specifically described herein. [Industrial applicability]

[0052] This invention is useful because it provides a plasma processing apparatus that can achieve further improvements in plasma processing efficiency compared to conventional plasma processing apparatuses that irradiate an object with plasma-like gas. [Explanation of symbols]

[0053] 100 Plasma Processing Equipment 10. First Plasma Generation Unit 20. Second Plasma Generation Unit 30 Mixed plasma generation section G1 First gas G2 Second gas P1 Plasma 1 P2 Second Plasma P 1+2 Mixed gas plasma P C Mixed plasma T object h1, h2 focal length

Claims

1. A plasma processing apparatus for treating an object with plasma, The aforementioned plasma processing apparatus is It has a first plasma generation unit that converts a first gas into plasma, and a second plasma generation unit that converts a second gas different from the first gas into plasma, A plasma processing apparatus configured to irradiate an object with a mixed plasma obtained by mixing a first plasma generated in the first plasma generation unit and a second plasma generated in the second plasma generation unit.

2. The plasma processing apparatus according to claim 1, further comprising a mixed plasma generation unit for mixing the first plasma generated in the first plasma generation unit and the second plasma generated in the second plasma generation unit without exposing them to the external atmosphere.

3. The plasma apparatus according to claim 1, wherein the first gas and the second gas are any of carbon dioxide, argon, helium, water vapor, nitrogen (including nitrogen zincide), carbon tetrafluoride, sulfur hexafluoride, oxygen, air, or a mixture thereof.

4. The plasma processing apparatus further comprises a third gas supply unit for supplying a third gas or a third plasma generation unit for converting the third gas into plasma, The plasma processing apparatus according to claim 1, configured to mix the third gas supplied from the third gas supply unit, or the third plasma generated in the third plasma generation unit, with the mixed plasma obtained by mixing the first plasma generated in the first plasma generation unit and the second plasma generated in the second plasma generation unit.

5. The plasma processing apparatus according to any one of claims 1 to 4, wherein the plasma processing is atmospheric pressure plasma processing.

6. A plasma treatment method for treating an object with plasma, A plasma treatment method comprising discharging the mixed plasma onto the treatment surface of an object using the plasma treatment apparatus described in claim 1.

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