Plasma irradiation unit, and plasma irradiation device

Abstract

To provide a plasma irradiation unit capable of efficiently presenting effects by irradiation with plasma in simple configuration, and a plasma irradiation device.SOLUTION: A plasma irradiation unit comprises a first electrode, a second electrode, an irradiation port, and a gas supply section. The second electrode is disposed while being spaced apart from the first electrode so as to configure a flow passage of a mixture gas, which is obtained by mixing a reactive gas into a raw material gas to be a raw material of a plasma gas, between the second electrode and the first electrode. The irradiation port irradiates a subject with the plasma gas generated by applying a voltage from the first electrode and the second electrode to the mixture gas flowing in the flow passage. The gas supply section generates the mixture gas by mixing the reactive gas to the raw material gas and supplies the mixture gas to the flow passage. The gas supply section configures a flow passage of the raw material gas, includes a suction port communicating to a negative pressure region, in which a negative pressure is generated by the flow of the raw material gas, and sucks the reactive gas from the suction port.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a plasma irradiation unit and a plasma irradiation device. [Background technology]

[0002] Plasma irradiation devices are used in the manufacturing process of, for example, plastics, paper, fibers, semiconductors, liquid crystals, films, etc. For example, by irradiating a workpiece with plasma using a plasma irradiation device, surface treatment can be performed to improve the hydrophilicity, adhesiveness, or print adhesion of the surface of the workpiece. In addition, by irradiating the workpiece with plasma, it is also possible to remove and clean organic matter present on the surface of the workpiece, and form an oxide film on the surface of the workpiece.

[0003] Patent Documents 1 and 2 disclose plasma generating devices of a dielectric barrier discharge type. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2023-40527 A [Patent Document 2] JP 2023-62318 A Summary of the Invention [Problem to be solved by the invention]

[0005] When performing surface modification using plasma irradiation, it is important to achieve the desired effect efficiently in a short time. There is a demand for technology that can solve this problem without complicating the device configuration.

[0006] In view of the above circumstances, an object of the present invention is to provide a plasma irradiation unit and a plasma irradiation device that are capable of efficiently exerting the effects of plasma irradiation with a simple configuration. [Means for solving the problem]

[0007] In order to achieve the above object, a plasma irradiation unit according to one embodiment of the present invention includes a first electrode, a second electrode, an irradiation port, and a gas supply unit. The second electrode is disposed at a distance from the first electrode so that a flow path for a mixed gas in which a raw material gas serving as a raw material for a plasma gas is mixed with a reactive gas is formed between the second electrode and the first electrode. The irradiation port irradiates a plasma gas, which is generated by applying a voltage to the mixed gas flowing through the flow path by the first electrode and the second electrode, toward a target object. The gas supply unit mixes the source gas with the reactive gas to generate the mixed gas, and supplies the mixed gas to the flow path. The gas supply unit forms a flow path for the source gas, has a suction port communicating with a negative pressure region where negative pressure is generated by the flow of the source gas, and draws in the reactive gas from the suction port.

[0008] In this plasma irradiation unit, the gas supply unit sucks in the reactive gas from a suction port that communicates with a negative pressure region where negative pressure is generated by the flow of the raw material gas, and the raw material gas and the reactive gas are mixed to generate a mixed gas. This makes it possible to generate a mixed gas with a simple configuration. In addition, by generating a plasma gas using the mixed gas, it becomes possible to efficiently exert the effect of plasma irradiation.

[0009] The plasma irradiation unit may further include a dielectric member disposed between the first electrode and the second electrode and constituting a flow path of the mixed gas between at least one of the first electrode and the second electrode. In this case, the plasma gas may be generated by applying a voltage to the mixed gas flowing through the flow path by the first electrode and the second electrode through the dielectric member.

[0010] The gas supply unit may include a Venturi tube. In this case, the Venturi tube may form a flow path for the source gas, have the suction port communicating with the negative pressure region, and suck in the reactive gas from the suction port.

[0011] The gas supply unit may include a flow rate adjustment unit that adjusts the flow rate of the reactive gas supplied to the suction port.

[0012] The Venturi tube may have an inlet through which the raw material gas flows, an outlet through which the mixed gas flows, and a nozzle portion configured between the inlet and the outlet and having a flow path cross-sectional area decreasing along the flow direction of the raw material gas. In this case, the suction port may be connected to the negative pressure region including an end portion of the nozzle portion on the outlet side.

[0013] The gas supply unit may include a diffuser unit configured between the nozzle unit and the outlet port.

[0014] The source gas may be nitrogen gas, helium gas, argon gas, carbon dioxide gas, or any combination of these gases.

[0015] The reactive gas may be air, oxygen gas, hydrogen gas, water vapor, hydrogen peroxide gas, organic gas, ammonia gas, or any combination of these gases.

[0016] The reactive gas may be air.

[0017] The flow rate of the raw material gas flowing into the inlet may be 10 L / min or more.

[0018] The flow rate of the raw material gas contained in the mixed gas supplied to the flow passage may be 10 L / min or more.

[0019] A flow rate of the reactive gas supplied to the suction port may be equal to or lower than a flow rate of the source gas flowing into the inlet.

[0020] A flow rate of the reactive gas contained in the mixed gas supplied to the flow passage may be equal to or less than a flow rate of the source gas contained in the mixed gas supplied to the flow passage.

[0021] A composition ratio of the reactive gas contained in the mixed gas supplied to the flow passage may be equal to or lower than a composition ratio of the source gas contained in the mixed gas supplied to the flow passage.

[0022] The gas supply unit may include an ejector pump having the Venturi tube.

[0023] The object may be carbon fiber reinforced plastic.

[0024] A plasma irradiation device according to one aspect of the present invention is a plasma irradiation device including the plasma irradiation unit, and further including a holding mechanism that holds an object to be irradiated with plasma gas by the plasma irradiation unit.

[0025] The plasma irradiation device may further include a transport mechanism that transports the object held by the holding mechanism relatively to the plasma irradiation unit. Effect of the Invention

[0026] As described above, according to the present invention, it is possible to efficiently exert the effects of plasma irradiation with a simple configuration. Note that the effects described here are not necessarily limited, and may be any of the effects described in this disclosure. [Brief description of the drawings]

[0027] [Figure 1] 1 is a schematic diagram of a plasma irradiation device according to an embodiment when viewed from a transport direction. [Diagram 2] 2 is a schematic cross-sectional view of the plasma irradiation device shown in FIG. 1 taken along line AA. [Diagram 3] FIG. 4 is a schematic diagram showing a configuration example of a gas mixing piping section. [Figure 4] FIG. 13 is a schematic diagram showing another example of the configuration of the Venturi tube. [Diagram 5] 1 is a graph showing the results of an investigation into the relationship between irradiation of a mixed gas consisting of raw material gas=nitrogen gas and reactive gas=oxygen-containing air and the adhesive strength / contact angle of CFRP. [Figure 6] FIG. 13 is a schematic diagram showing a configuration example of a plasma irradiation device according to another embodiment. [Figure 7] 13 is a schematic diagram showing a configuration example of a plasma irradiation head according to another embodiment. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0029] [Plasma irradiation device] 1 and 2 are schematic diagrams showing a configuration example of a plasma irradiation device according to one embodiment of the present invention.

[0030] The plasma irradiation device 1 is configured as an atmospheric pressure plasma (APP) irradiation device, which generates plasma at atmospheric pressure and irradiates the workpiece W with plasma gas PG. The plasma irradiation device can also be called a plasma generating device. The irradiation of the workpiece W with the plasma gas PG can also be said to be the transportation of the plasma gas PG to the workpiece W.

[0031] In this embodiment, the plasma irradiation device 1 has a plasma irradiation unit 2 and a holding mechanism 3 that holds a workpiece W, which is an object to be irradiated with plasma gas PG by the plasma irradiation unit 2. The plasma irradiation device 1 also has a transport mechanism 4 that transports the workpiece W held by the holding mechanism 3 relative to the plasma irradiation unit 2. In this disclosure, the irradiation of the plasma gas PG corresponds to the irradiation of plasma. It is the active species generated in the plasma gas PG that actually do the work to exert the effect of surface modification, etc.

[0032] In the following description, it is assumed that the workpiece W is transported along the X direction in the XY plane direction as shown in Figures 1 and 2. Then, it is assumed that the plasma gas PG is irradiated to the workpiece W by the plasma irradiation unit 2 along the Z direction perpendicular to the XY plane direction.

[0033] The X direction in the figure is described as the conveying direction (the positive side of the X axis is the downstream side, and the negative side is the upstream side), the Y direction in the figure is described as the width direction (the positive side of the Y axis is the left side, and the negative side is the right side), and the Z direction in the figure is described as the up-down direction (the positive side of the Z axis is the upper side, and the negative side is the lower side).

[0034] Of course, the application of this technology is not limited to the direction in which the plasma irradiation unit 2 is arranged (the direction in which the plasma gas PG is irradiated), the transport direction of the workpiece W, or the like.

[0035] Fig. 1 is a schematic diagram of a plasma irradiation device 1 as viewed from the upstream side along the conveying direction (X direction). Fig. 2 is a cross-sectional view showing a cross section of the plasma irradiation device 1 shown in Fig. 1 taken along line AA.

[0036] The present invention can be applied to any object, and there is no limitation on the type of workpiece W to be irradiated with the plasma gas PG by the plasma irradiation device 1. For example, the plasma irradiation device 1 can be used to irradiate the plasma gas PG to substrates, carbon fiber reinforced plastics (CFRP), semiconductor parts, liquid crystal elements, fibers, paper, plastics, films, and the like.

[0037] As the holding mechanism 3, any configuration capable of holding the workpiece W, such as a work stage, may be adopted. As the transport mechanism 4, any configuration capable of transporting the workpiece W held by the holding mechanism 3 relatively to the plasma irradiation unit 2 may be adopted. For example, in order to construct the holding mechanism 3 and the transport mechanism 4, any moving mechanism, such as a linear stage using a stepping motor or the like, or any rotating mechanism using a gear mechanism or the like, may be used.

[0038] For example, a configuration may be adopted in which the work stage is placed on a base (platen) and moved in a magnetically levitated state by a linear motor. In this case, the work stage functions as the holding mechanism 3, and a mechanism for moving the work stage by the linear motor functions as the transport mechanism 4.

[0039] Alternatively, the work stage or the work W itself may be placed and held on a conveyor belt that moves in one direction. When the work stage is moved by the conveyor belt, the work stage functions as the holding mechanism 3, and the conveyor belt and the mechanism that moves the conveyor belt function as the conveying mechanism 4. When the work W itself is moved by the conveyor belt, the conveyor belt functions as the holding mechanism 3 and also functions as the conveying mechanism 4.

[0040] In addition, for example, a configuration may be adopted in which a sheet-like workpiece W is pulled out from a feed roller and wound up by a take-up roller. In this case, the feed roller, the take-up roller, a mechanism for rotating each roller, and the like function as the holding mechanism 3 and also function as the conveying mechanism 4.

[0041] It is also possible to adopt a configuration in which the workpiece W held by a work stage or the like is fixed, and the plasma irradiation unit 2 moves relative to the workpiece W. In this case, the workpiece stage functions as the holding mechanism 3, and a mechanism for moving the plasma irradiation unit 2 functions as the transport mechanism 4.

[0042] In this way, any configuration may be adopted for the holding mechanism 3 and the transport mechanism 4. The holding mechanism 3 and the transport mechanism 4 are not necessarily limited to being clearly separated, and one member may function as both the holding mechanism 3 and the transport mechanism 4. Note that the example shown in Figs. 1 and 2 illustrates a form in which a sheet-like workpiece W is transported along the transport direction (X direction).

[0043] The plasma irradiation device 1 is not limited to a so-called transport type, and may be a so-called batch type in which the workpiece W is fixed and placed on a work stage or the like and is irradiated with plasma gas PG by the plasma irradiation unit 2. That is, a configuration in which only the holding mechanism 3 is constructed and the transport mechanism 4 is not constructed may be employed.

[0044] The irradiation of the plasma gas PG by the plasma irradiation unit 2 and the transportation of the workpiece W by the transportation mechanism 4 are controlled, for example, by a controller (not shown). The controller has hardware necessary for configuring a computer, such as a processor such as a CPU, a GPU, or a DSP, a memory such as a ROM or a RAM, and a storage device such as a HDD. For example, the processor loads a program according to the present technology, which is pre-recorded in a ROM or the like, into a RAM and executes the program, thereby executing the plasma irradiation method according to the present technology.

[0045] The controller is one element constituting the plasma irradiation device 1. The specific configuration of the controller is not limited, and any computer such as a PC may be used. Of course, hardware such as FPGA and ASIC may be used. The location where the controller is configured is also not limited, and may be designed arbitrarily.

[0046] The program is installed in the controller via, for example, various recording media. Alternatively, the program may be installed via the Internet or the like. There are no limitations on the type of recording medium on which the program is recorded, and any computer-readable recording medium may be used. For example, any computer-readable non-transitory storage medium may be used.

[0047] [Plasma irradiation unit] 1 and 2, the plasma irradiation unit 2 is configured as a dielectric barrier discharge type plasma irradiation unit, and includes a plasma irradiation head 6, a gas supply mechanism 7, and a voltage application mechanism 8. Note that the voltage application mechanism 8 is omitted in Fig. 1. Also, in Fig. 2, with regard to the gas supply mechanism 7, only a portion (mixed gas supply pipe 25) connected to the plasma irradiation head 6 is shown.

[0048] 1 and 2, the plasma irradiation head 6 has an approximate outer shape of a flat plate extending in one direction. The plasma irradiation head 6 has a first electrode 9, a second electrode 10, and a dielectric member 11.

[0049] 1, when the plasma irradiation head 6 is viewed from the upstream side along the transport direction (X direction), the rear surface 10b located on the upstream side of the second electrode 10 is seen as the front. The rear surface 10b of the second electrode 10 has a rectangular shape with the long side direction parallel to the width direction (Y direction) and the short side direction parallel to the up-down direction (Z direction).

[0050] The shape of the back surface 10b of the second electrode 10 is equal to the outer shape of the plasma irradiation head 6 when viewed along the transport direction (X direction). In addition, the shape of the back surface 11b located on the upstream side of the dielectric member 11 is equal to the shape of the back surface 10b of the second electrode 10.

[0051] 2, the surface 10a located on the downstream side of the second electrode 10 has three sides, the upper side, left side, and right side, which protrude toward the downstream side by a predetermined amount. These protruding parts are abutted against and connected to the three sides, the upper side, left side, and right side, of the back surface 11b of the dielectric member 11.

[0052] As a result, a gap is formed between the recess (the inner peripheral portion surrounded by the protruding portion) of the surface 10a of the second electrode 10 and the back surface 11b of the dielectric member 11. This gap serves as a flow path FP for the mixed gas supplied from the gas supply mechanism 7. In addition, the gap (the bottom end of the flow path FP) between the lower end of the second electrode 10 and the lower end of the dielectric member 11 serves as an irradiation port 12 for irradiating the plasma gas PG toward the target workpiece W. The irradiation port 12 for the plasma gas PG is formed in a slit shape extending in the width direction (Y direction).

[0053] The first electrode 9 is disposed on a surface 11a of the dielectric member 11. Therefore, the first electrode 9 and the second electrode 2 are disposed at a distance from each other.

[0054] The size of the first electrode 9 in the width direction (Y direction) is approximately equal to the size of the surface 11a of the dielectric member 11 in the width direction (Y direction). In addition, as shown in Fig. 2, the size of the first electrode 9 in the up-down direction (Z direction) is smaller than the size of the surface 11a of the dielectric member 11 in the up-down direction (Z direction).

[0055] When the surface 11a of the dielectric member 11 is viewed from the downstream side along the transport direction (X direction), a first electrode 9 is disposed at the center in the up-down direction (Z direction) and across the width direction (Y direction).

[0056] 1 and 2 show six through holes. The through holes are aligned in the width direction (Y direction). The through holes serve as supply ports 13 through which a mixed gas is supplied from a gas supply mechanism 7 to a flow path FP formed between the second electrode 10 and the dielectric member 11.

[0057] The configuration for supplying the mixed gas to the flow path FP formed between the second electrode 10 and the dielectric member 11 is not limited. For example, a supply port 13 communicating with the flow path FP may be formed in the upper surface of the second electrode 10. Also, a slit-shaped supply port extending in the width direction (Y direction) may be formed in the second electrode 10.

[0058] From the viewpoint of durability, ceramics is preferable as the material of the dielectric member 11. Examples of ceramics include aluminum oxide (Al2O3), aluminum nitride (AlN), and steatite. These materials have a relatively low relative dielectric constant, a relatively high strength, and excellent durability. Of course, the material is not limited to these materials.

[0059] The material of the first electrode 9 and the second electrode 10 is not particularly limited, but is preferably one with high conductivity, and typical examples include copper (Cu), silver (Ag), aluminum (Al), and gold (Au). Of course, other materials may be used. The first electrode 9 may also be made of a metal foil such as copper foil or aluminum foil. The first electrode 9 and the second electrode 10 may also be made by applying a conductive paste such as silver (Ag) and then baking it.

[0060] [Voltage application mechanism] The voltage application mechanism 8 generates a voltage difference between the first electrode 9 and the second electrode 10. In this embodiment, the first electrode 9 is used as a high-voltage side electrode and is connected to an AC voltage source. The method of connecting the AC voltage source and the first electrode 9 is not particularly limited as long as the method is electrically connected and can withstand the applied voltage.

[0061] The second electrode 10 is used as a low-voltage side electrode and is connected to a ground potential directly or via a resistor. The configuration for generating a voltage difference between the first electrode 9 and the second electrode 10 is not limited, and any configuration may be adopted. For example, it is possible to use the first electrode 9 as a low-voltage side electrode and the second electrode 10 as a high-voltage side electrode.

[0062] By driving the voltage application mechanism 8, a voltage is applied to the mixed gas flowing through the flow path FP formed between the second electrode 10 and the dielectric member 11 via the dielectric member 11. By applying the voltage, the mixed gas is turned into plasma, and a plasma gas PG is generated. The generated plasma gas PG is irradiated toward the workpiece W from an irradiation port 12 formed between the lower end of the second electrode 10 and the lower end of the dielectric member 11.

[0063] Thus, the plasma irradiation head 6 has a first electrode 9 and a second electrode 10 arranged at a distance from the first electrode 9. The plasma irradiation head 6 also has a dielectric member 11 arranged between the first electrode 9 and the second electrode 10, and between at least one of the first electrode 9 and the second electrode 10, which constitutes a flow path FP for a mixed gas in which a reactive gas is mixed with a raw material gas that is a raw material for the plasma gas PG.

[0064] 2, the dielectric member 11 is disposed so as to define a mixed gas flow path FP between the dielectric member 11 and the second electrode 10. Without being limited thereto, the dielectric member 11 may be disposed so as to define a mixed gas flow path FP between the dielectric member 11 and the first electrode 9.

[0065] The plasma irradiation head 6 also has an irradiation port 12 that irradiates the plasma gas PG generated by applying a voltage to the mixed gas flowing through the flow path FP by the first electrode 9 and the second electrode 10 via the dielectric member 11 toward the target workpiece W.

[0066] The configuration of the plasma irradiation head 6 is not limited to the configuration exemplified in Figures 1 and 2. Any configuration capable of generating atmospheric pressure plasma by the dielectric barrier discharge method may be adopted.

[0067] [Gas supply mechanism] The gas supply mechanism 7 generates a mixed gas by mixing a raw material gas, which is a raw material of the plasma gas PG, with a reactive gas, and supplies the mixed gas to a flow path FP of the plasma gas PG formed in the plasma irradiation head 6. As shown in FIG. 1, the gas supply mechanism 7 has a raw material gas piping section 15, a reactive gas piping section 16, a gas mixing piping section 17, and a mixed gas piping section 18.

[0068] In this embodiment, the gas supply mechanism 7 corresponds to one embodiment of a gas supply unit according to the present invention.

[0069] The raw material gas piping section 15 includes a raw material gas piping 19 and a flow rate adjustment section 20. One end of the raw material gas piping 19 is connected to a raw material gas supply source (e.g., a cylinder, etc.) not shown. The other end of the raw material gas piping 19 is connected to the gas mixing piping section 17.

[0070] The flow rate adjusting unit 20 adjusts the flow rate of the raw material gas supplied to the gas mixing piping unit 17 through the raw material gas piping 19. The flow rate adjusting unit 20 is composed of an arbitrary flow rate adjusting valve such as a needle valve, and a flow meter. The raw material gas may also be called a plasma generating gas.

[0071] The reactive gas piping section 16 has a reactive gas piping 21 and a flow rate adjustment section 22. One end of the reactive gas piping 21 is connected to, for example, a reactive gas supply source (e.g., a cylinder, etc.) not shown. When air is mixed as the reactive gas, one end of the reactive gas piping 21 is disposed in the atmosphere. The other end of the reactive gas piping 21 is connected to the gas mixing piping section 17.

[0072] The flow rate adjusting unit 22 adjusts the flow rate of the reactive gas supplied to the gas mixing piping unit 17 through the reactive gas piping 21. The flow rate adjusting unit 22 can be configured with any flow rate adjusting valve, such as a needle valve, and a flow meter. When air is mixed as the reactive gas, a leak valve configuration can be adopted.

[0073] The gas mixing piping section 17 mixes the raw material gas supplied from the raw material gas piping 19 with the reactive gas supplied from the reactive gas piping 21 to generate a mixed gas. The generated mixed gas is supplied to the mixed gas piping section 18.

[0074] The mixed gas piping section 18 has a mixed gas inlet pipe 23 , a manifold 24 , and six mixed gas supply pipes 25 .

[0075] The mixed gas inlet pipe 23 is connected to the gas mixing pipe section 17. The manifold 24 is a pipe extending in the width direction (Y direction), and is connected to the mixed gas inlet pipe 23. One end of each of the six mixed gas supply pipes 25 is connected to the manifold 24. The other end of each of the six mixed gas supply pipes 25 is connected to six supply ports 13 formed on the back surface 11b of the second electrode 10.

[0076] The mixed gas flowing out from the gas mixing piping section 17 flows into the manifold 24 through the mixed gas inlet piping 23. The manifold 24 also functions as a buffer space for the mixed gas, which is advantageous for improving the uniformity of the mixed gas. The mixed gas flows out from the manifold 24 to six mixed gas supply pipings 25, and is supplied from the supply port 13 to the flow path FP in the plasma irradiation head 6.

[0077] [Gas mixing piping section] 3 is a schematic diagram showing a configuration example of the gas mixing piping section 17. The gas mixing piping section 17 has a Venturi tube 27 that constitutes a flow path of the raw material gas. The inside of the Venturi tube 27 becomes the flow path of the raw material gas, and the reactive gas is sucked from a suction port 28 that communicates with a negative pressure region NA where negative pressure is generated by the flow of the raw material gas. As a result, a mixed gas in which the reactive gas is mixed with the raw material gas is generated.

[0078] 3, the Venturi tube 27 has an inlet 29 through which the raw material gas flows in, an outlet 30 through which the mixed gas flows out, and an inlet 28 through which the reactive gas is sucked in. The Venturi tube 27 also has a nozzle section 31 that is configured between the inlet 29 and the outlet 30 and whose flow path cross-sectional area decreases along the flow direction of the raw material gas. The end of the nozzle section 31 on the outlet 30 side becomes a throat section 32 whose flow path cross-sectional area is the smallest.

[0079] The inlet 29 is connected to the source gas pipe 19 of the source gas pipe unit 15. The flow rate of the source gas flowing into the inlet 29 of the Venturi tube 27 is adjusted by the flow rate adjustment unit 20 of the source gas pipe unit 15.

[0080] The source gas flowing in from the inlet 29 flows inside the nozzle portion 31, and the flow velocity increases and the pressure decreases at the throat portion 32, which is the end portion on the outlet 30 side. As a result, negative pressure is generated in the region including the throat portion 32, and a negative pressure region NA is formed.

[0081] The suction port 28 through which the reactive gas is sucked is formed to communicate with the negative pressure area NA. The reactive gas pipe 21 of the reactive gas piping section 16 is connected to the suction port 28. In Fig. 3, a needle valve is illustrated as the flow rate adjustment section 22 of the reactive gas piping section 16. The flow rate of the reactive gas supplied to the suction port 28 is adjusted by the needle valve.

[0082] 3, the Venturi tube 27 has a diffuser portion 33. The diffuser portion 33 is configured between the nozzle portion 31 (throat portion 32) and the outlet port 30. The end of the diffuser portion 33 opposite to the nozzle portion 31 side becomes the outlet port 30.

[0083] The diffuser 33 sufficiently mixes the raw material gas with the reactive gas sucked from the suction port 28, improving the uniformity of the mixed gas. By uniformly mixing the raw material gas with the mixed gas, the plasma irradiation head 6 can efficiently generate the plasma gas PG. For example, it is possible to suppress the variation in oxygen concentration of the reactive gas in the mixed gas flowing out from the outlet 30 to 10% or less.

[0084] For example, when nitrogen gas (N2) was used as the source gas and air containing oxygen (O2) was used as the reactive gas, it was possible to suppress the variation in oxygen concentration in the mixed gas to within ±5%. Similar results were obtained with other types of gases.

[0085] As shown in Fig. 3, in this embodiment, the diffuser section 33 has a suction section 34 whose flow path cross-sectional area decreases along the flow direction of the mixed gas, and a pressure booster section 35 connected to the suction section 34 whose flow path cross-sectional area increases along the flow direction of the mixed gas. The suction section 34 mainly performs the function of sucking the mixed gas. The pressure booster section 35 mainly performs the function of recovering pressure. The specific configuration of the diffuser section 33 is not limited and may be designed arbitrarily.

[0086] Fig. 4 is a schematic diagram showing another example of the configuration of the Venturi tube. The Venturi tube 27 shown in Fig. 4 is connected to a nozzle section 31 and a diffuser section 33. The diffuser section 33 has a configuration in which the flow path cross-sectional area increases along the flow direction of the mixed gas, and the end section on the nozzle section 31 side has the smallest flow path area.

[0087] The throat section 32, where the flow area of ​​the nozzle section 31 is the smallest, is connected to the end of the diffuser section 33 on the nozzle section 31 side, where the flow area of ​​the diffuser section 33 is the smallest. A negative pressure region NA is formed to include this connected portion. The suction port 28, through which the reactive gas is sucked, is formed at the connected portion between the nozzle section 31 and the diffuser section 33 so as to communicate with the negative pressure region NA. A Venturi tube 27 having such a configuration can also be adopted.

[0088] Alternatively, any configuration including the Venturi tube 27 may be adopted as the gas mixing piping section 17. For example, an ejector pump having the Venturi tube 27 can be used as the gas mixing piping section 17.

[0089] For example, a single-stage ejector pump may be used, or a multi-stage ejector pump may be used. Alternatively, the gas mixing piping section 17 may be realized by using an ejector pump having various configurations including a Venturi tube 27. In addition, the gas mixing piping section 17 may have a configuration in which the diffuser section 33 is not used.

[0090] [Types of raw material gases and reactive gases] As the type of raw material gas, for example, nitrogen gas, helium gas, argon gas, carbon dioxide gas, etc. may be used. Alternatively, a gas in which these gases are mixed in any combination may be used as the raw material gas. However, the raw material gas is not limited to this, and other inert gases, etc. may be used.

[0091] The reactive gas is a gas of an element to be mixed into the raw material gas, or a gas containing an element to be mixed into the raw material gas. For example, the reactive gas may be air, oxygen gas (O2), hydrogen gas (H2), water vapor (H2O), hydrogen peroxide gas (H2O2), organic gas, ammonia gas (NH3), or the like. Alternatively, the reactive gas may be a gas in which these gases are mixed in any combination. The organic gas may be, for example, an organic gas containing alcohols, formic acid, acrylic acid, or the like. The reactive gas is not limited to these. Other gases may be used.

[0092] For example, when air containing oxygen is used as the reactive gas, it is possible to increase the oxygen radical concentration in the plasma gas PG generated by the discharge. This enhances the effect of surface cleaning of the workpiece W, for example, by breaking the bonds of organic matter with the oxygen radicals, or by bonding between the oxygen radicals and organic matter. In addition, the effect of surface modification by introducing functional groups to the surface of the workpiece W, improving hydrophilicity and adhesion (improving wettability), and oxidation treatment, etc. are enhanced.

[0093] In addition, when hydrogen gas is used as the reactive gas, it is possible to increase the concentration of hydrogen radicals in the plasma gas PG generated by the discharge. This makes it possible to reduce the oxide film formed on the surface of a metal member such as copper, and enhances the effect of surface modification such as improving solder wettability. It also makes it possible to quickly reduce the oxide film on the solder, achieving good bonding of copper electrodes, etc.

[0094] In addition, when water vapor is used as the reactive gas, or by incorporating water vapor into the air, it is possible to improve the effect of surface modification such as wettability. For example, by placing a bubbler containing water on the upstream side (the side exposed to the atmosphere) of the flow rate adjustment unit 22 that adjusts the flow rate of air and allowing it to circulate, it is possible to easily incorporate water vapor into the air.

[0095] Conversely, it is also possible to remove water vapor from air and use it as a reactive gas. For example, water vapor can be removed by passing the air through a hollow fiber filter or a column filled with a desiccant upstream of the flow rate regulator 22.

[0096] In addition, a gas of any element or a gas containing any element can be used as the reactive gas in order to efficiently improve the effect of irradiation with the plasma gas PG.

[0097] [Flow rate of raw material gas and reactive gas] The flow rate of the raw material gas flowing into the Venturi tube 27 is adjusted to a flow rate at which a negative pressure is generated by the flow of the raw material gas, and a negative pressure region NA is formed. In other words, the flow rate of the raw material gas flowing into the Venturi tube 27 can be arbitrarily adjusted within a range in which a negative pressure region NA is formed. For example, a negative pressure region NA can be formed in the Venturi tube 27 at a flow rate of 10 L / min or more. Of course, this is not limited to this, and a flow rate of 10 L / min or less may be adopted as long as a negative pressure region NA can be formed.

[0098] The flow rate of the raw material gas flowing into the Venturi tube 27 is approximately equal to the flow rate of the raw material gas contained in the mixed gas supplied to the flow path FP formed in the plasma irradiation head 6. Therefore, the flow rate of the raw material gas contained in the mixed gas supplied to the flow path FP can also be arbitrarily adjusted within a range in which a negative pressure region NA is formed in the Venturi tube 27. For example, the flow rate of the raw material gas contained in the plasma gas PG supplied to the flow path FP can be adjusted within a range of 10 L / min or more. Of course, this is not limited to this, and a flow rate of 10 L / min or less may be adopted.

[0099] In addition, by arranging a plurality of Venturi tubes 27 in parallel with respect to the plasma irradiation head 6, it is possible to increase the flow rate of the raw material gas to the plasma irradiation head 6. Therefore, it is possible to apply the present invention without limiting the upper limit of the raw material gas supplied to the plasma irradiation head 6. Of course, it is also possible to design with a set upper limit, for example, by setting the flow rate of the raw material gas in the range of 10 L / min or more and 500 L / min or less.

[0100] The flow rate of the reactive gas sucked through the suction port 28 of the Venturi tube 27 is determined by the magnitude of the negative pressure generated in the Venturi tube 27, and the pressure loss in the mixed gas piping section 18 and the supply port 13 shown in Fig. 1. By appropriately designing the nozzle section 31 of the Venturi tube 27, etc., it is possible to suck in the reactive gas within a range equal to or less than the flow rate of the raw material gas.

[0101] Therefore, it is possible to adopt a design in which the flow rate of the reactive gas supplied to the suction port 28 of the Venturi tube 27 is adjusted within a range equal to or less than the flow rate of the raw material gas flowing into the inlet 29. Typically, a minute amount of reactive gas is drawn in compared to the flow rate of the raw material gas.

[0102] The flow rate of the reactive gas sucked into the Venturi tube 27 is approximately equal to the flow rate of the reactive gas contained in the mixed gas supplied to the flow path FP formed in the plasma irradiation head 6. Therefore, the flow rate of the reactive gas contained in the mixed gas supplied to the flow path FP can be adjusted within a range equal to or less than the flow rate of the raw material gas flowing into the inlet 29.

[0103] Moreover, the flow rate of the source gas flowing into the inlet 29 is substantially equal to the flow rate of the source gas contained in the mixed gas supplied to the flow path FP. In consideration of this, it can be said that the flow rate of the reactive gas contained in the mixed gas supplied to the flow path FP can be adjusted within a range equal to or less than the flow rate of the source gas contained in the mixed gas supplied to the flow path FP.

[0104] When this is described with a focus on the composition ratio of the source gas and the reactive gas contained in the mixed gas, the composition ratio of the reactive gas contained in the mixed gas supplied to the flow path FP can be adjusted within a range equal to or less than the composition ratio of the source gas contained in the mixed gas supplied to the flow path FP. Of course, the adjustment is not limited to such a composition ratio.

[0105] When a gas containing a mixture of multiple gases is used as the raw material gas, the "composition ratio of the raw material gas contained in the mixed gas" is the sum of the composition ratios of the multiple gases contained in the raw material gas. When a gas containing a mixture of multiple gases is used as the reactive gas, the "composition ratio of the reactive gas contained in the mixed gas" is the sum of the composition ratios of the multiple gases contained in the reactive gas.

[0106] In the plasma irradiation device 1 shown in FIGS. 1 to 3, irradiation with the plasma gas PG was carried out under the following conditions. Source gas: Nitrogen gas Reactive gas: Air containing oxygen Power: 240W Slit width (size of irradiation port 12 in the conveying direction (X direction)): 0.3 mm Effective length (size of irradiation port 12 in the width direction (Y direction)): 200 mm Irradiation gap: Distance from irradiation port 12 to workpiece W: 2 mm Mixed gas flow rate: 80L / min

[0107] In this embodiment, the flow rate of nitrogen gas can be adjusted by the flow rate adjustment unit 20. Also, the flow rate of air can be adjusted by the flow rate adjustment unit 22. This makes it possible to realize a mixed gas with a desired flow rate, and also makes it possible to adjust the oxygen concentration in the mixed gas with high precision.

[0108] For example, by setting the flow rate of nitrogen gas to 79.6 L / min and the flow rate of air to 0.4 L / min, it is possible to supply a mixed gas with an oxygen concentration of 0.1% to the plasma irradiation head 6. Also, by setting the flow rate of nitrogen gas to 76.0 L / min and the flow rate of air to 4.0 L / min, it is possible to supply a mixed gas with an oxygen concentration of 1.0% to the plasma irradiation head 6.

[0109] The control of the flow rate and mixture concentration of the mixed gas will be explained using an example in which the raw material gas is nitrogen gas and the reactive gas is air containing oxygen. Specifically, an example of a method for setting the oxygen concentration to a desired value with a mixed gas flow rate of 80.0 L / min will be explained.

[0110] First, nitrogen gas is supplied at a predetermined flow rate so that a negative pressure region NA is formed in the Venturi tube 27. The flow rate adjustment unit 22 adjusts the air flow rate to a calculated flow rate that takes into account pressure loss and the like (a flow rate that results in a desired oxygen concentration).

[0111] Thereafter, the nitrogen gas flow rate is adjusted so that the total flow rate of the mixed gas (nitrogen gas flow rate + air flow rate) is 80.0 L / min, and the air flow rate is adjusted so that the desired oxygen concentration is achieved in conjunction with the nitrogen gas adjustment. This adjustment process is repeated multiple times, and the flow rates of the nitrogen gas and air are each controlled so that the total flow rate is 80.0 L / min and the desired oxygen concentration is achieved. This makes it possible to achieve the desired oxygen concentration with a mixed gas flow rate of 80.0 L / min. It is also possible to automatically control the flow rate and mixed concentration using a computer.

[0112] It is also possible to place a flow rate regulator for regulating the flow rate of the mixed gas in the mixed gas inlet pipe 23 of the mixed gas pipe section 18. However, if a flow rate regulator is placed in this position, there is a possibility that the flow rate regulator will cause a pressure loss and the pressure in the negative pressure area NA will increase. This will affect the suction of the reactive gas, so care must be taken.

[0113] [Effects of plasma gas irradiation] As mentioned above, the irradiation of the plasma gas PG makes it possible to modify the surface of the workpiece W, for example, to improve hydrophilicity, adhesiveness, print adhesion, etc. In addition, the irradiation of the plasma gas PG also makes it possible to remove and clean organic matter. In addition, the irradiation of the plasma gas PG also makes it possible to form an oxide film on the surface of the workpiece W, reduce the oxide film, and decorate the surface with specific chemical substances.

[0114] For example, plasma gas PG is irradiated as a pretreatment for the bonding process. For example, plasma gas PG is irradiated onto the bonding surface of various workpieces W, such as metals and resins. This introduces hydrophilic groups to the surface of the workpiece W, improving wettability and improving the adhesive strength of the adhesive and the adhesion of coatings and printing inks.

[0115] In addition, when carbon fiber reinforced plastics (CFRP) are bonded together with epoxy adhesive, the bonding surface is irradiated with plasma gas PG, which introduces hydrophilic groups to improve wettability and causes some functional groups to form strong chemical bonds, increasing the interfacial adhesive strength.

[0116] In this embodiment, the plasma gas PG is generated using a mixed gas in which a raw material gas is mixed with a reactive gas, which makes it possible to efficiently exert these effects.

[0117] FIG. 5 is a graph showing the results of examining the relationship between the irradiation of a mixed gas consisting of raw material gas=nitrogen gas and reactive gas=oxygen-containing air and the adhesive strength / contact angle of CFRP.

[0118] A PAN-based UD (Uni-Directional) material was used as the sample CFRP. The adhesive strength / contact angle of the sample CFRP was compared between those not exposed to plasma gas (exposure time 0 ms) and those exposed to plasma gas (exposure time 36 ms). The adhesive strength / contact angle was also compared when the oxygen concentration of the mixed gas was changed and plasma gas was exposed (exposure time 36 ms). The tensile shear strength was evaluated as the adhesive strength.

[0119] As shown in the graph in Figure 5, the results are as follows: Untreated (irradiation time 0 ms): Adhesive strength 4 MPa / contact angle 92 Deg Oxygen concentration 0.0% (irradiation time 36ms): Adhesive strength 14MPa / contact angle 73Deg Oxygen concentration 0.01% (irradiation time 36 ms): adhesive strength 21 MPa / contact angle 54° Oxygen concentration 0.1% (irradiation time 36 ms): adhesive strength 28 MPa / contact angle 40° Oxygen concentration 1.0% (irradiation time 36 ms): adhesive strength 24 MPa / contact angle 69°

[0120] In this verification, the oxygen radical concentration in the plasma gas PG was the highest, the adhesive strength was the highest, and the contact angle was the smallest at an oxygen concentration of 0.1% (irradiation time of 36 ms). In this way, by appropriately adjusting the flow rate of the reactive gas, it is possible to achieve a high effect by irradiating the plasma gas PG.

[0121] As described above, in the plasma irradiation device 1 and the plasma irradiation unit 2 according to the present embodiment, the raw material gas and the reactive gas are mixed by the gas supply mechanism 7 having the Venturi tube 27, and the mixed gas is generated. This makes it possible to generate the mixed gas with a simple configuration. In addition, by generating the plasma gas PG using the mixed gas, it becomes possible to efficiently exert the effect of the plasma irradiation.

[0122] Using an atmospheric pressure plasma irradiation device, plasma is generated by discharging a raw material gas (hereinafter, nitrogen gas is used as an example) at atmospheric pressure, and the plasma gas PG is irradiated onto the workpiece W. This makes it possible to achieve effects such as surface treatment (surface modification). For example, surface modification using an atmospheric pressure plasma irradiation device is used as an effective means for dry cleaning of the surface of a glass substrate, or as a pretreatment for bonding resins or metals.

[0123] Regarding the irradiation of such plasma gas PG, there have been cases where it was not possible to adopt this method for highly soiled workpieces W or for some applications (such as surface modification of CFRP) because it was difficult to perform sufficient cleaning / surface modification in a short period of time and the processing capacity was deemed insufficient.

[0124] In order to realize efficient irradiation of the plasma gas PG, it is possible to consider a method of increasing the irradiation length of the plasma irradiation device 1 (the size of the irradiation port 12 in the width direction (Y direction)). In other words, it is possible to consider a method of increasing the range in which the plasma gas PG can be irradiated. To realize this method, a flow rate of the raw material gas (nitrogen gas) proportional to the irradiation length is required, which increases the cost of the device and the running cost.

[0125] In this embodiment, a plasma gas PG is generated using a mixed gas in which a raw material gas (nitrogen gas) is mixed with a reactive gas (hereinafter, air containing oxygen is taken as an example), and is irradiated onto the workpiece W. This makes it possible to obtain a sufficient effect in a short period of time. In other words, it becomes possible to efficiently exert the effects of surface treatment (surface modification) and the like by irradiating the plasma gas PG.

[0126] One possible method for mixing oxygen into high-pressure nitrogen gas is to custom-order a nitrogen cylinder with a small amount of oxygen already mixed in. Another possible method is to use a precision gas mixer to mix gas from a nitrogen cylinder and an oxygen cylinder. However, these methods are expensive and difficult to adopt.

[0127] Another possible method is to mix in a small amount of oxygen by connecting an air supply pipe to a general pipe through which high-pressure nitrogen gas flows. With this method, the pipe through which a large flow of nitrogen flows is pressurized, so air does not easily enter, and even if it does enter, it is difficult to diffuse it evenly.

[0128] In this embodiment, a gas mixing piping section 17 including a Venturi tube 27 is configured as shown in Fig. 4 and Fig. 5. A negative pressure region NA is formed by the Venturi effect due to the flow of nitrogen gas at a large flow rate, and air can be sucked from a suction port 28 communicating with the negative pressure region NA.

[0129] This makes it possible to appropriately mix a small amount of oxygen with a simple configuration, and to generate plasma gas PG using the mixed gas. As a result, it is now possible to efficiently achieve effects such as surface modification at a sufficient processing speed, greatly expanding the practicality of applications that were previously difficult to apply.

[0130] In this embodiment, the flow rate of the reactive gas (air) provided to the suction port 28 of the Venturi tube 27 can be adjusted with high precision by the flow rate adjustment unit 22. This makes it possible to adjust the oxygen concentration in the mixed gas of nitrogen gas and air with high precision, thereby improving the effect of plasma irradiation. For example, by appropriately adjusting the oxygen concentration of the mixed gas, it becomes possible to increase the concentration of oxygen radicals generated by discharge, thereby making it possible to improve the processing speed of surface modification, etc.

[0131] Of course, the application of the present invention is not limited to the case where oxygen is mixed into nitrogen gas, but can also be applied to other cases where, for example, hydrogen gas, water vapor gas, hydrogen peroxide gas, etc. are mixed into the raw material gas as reactive gas.

[0132] <Other embodiments> The present invention is not limited to the above-described embodiment, and various other embodiments can be realized.

[0133] As mentioned above, when air is mixed as the reactive gas, the end of the reactive gas pipe 21 shown in Fig. 1 is placed in the atmosphere. In other words, a cylinder or the like that serves as a supply source of the reactive gas is not required, and it is possible to suppress the device from becoming complicated and large in size. As a result, it is possible to generate the mixed gas with a simpler configuration.

[0134] For example, a gas mixing pipe section 17 having a Venturi tube 27, as illustrated in Fig. 3 and Fig. 4, is disposed between the raw material gas supply port of a conventional atmospheric pressure plasma irradiation device and the raw material gas supply source. This makes it possible to easily generate a mixed gas in which air is mixed as a reactive gas. Naturally, there is no need to newly install a gas facility capable of supplying both the raw material gas and the reactive gas, and it is possible to efficiently exert the effect of plasma irradiation with a simple configuration.

[0135] 1 and 2, a dielectric barrier discharge type plasma irradiation unit is exemplified as the plasma irradiation unit 2. However, the present invention is not limited to this, and can be applied to plasma irradiation units of other types than the dielectric barrier discharge type.

[0136] For example, the plasma gas PG is generated by applying a voltage to the mixed gas by the first electrode 9 and the second electrode 10 without using the dielectric member 11. Any plasma irradiation unit having an arbitrary configuration capable of irradiating the generated plasma gas PG from the irradiation port 12 can be configured as the plasma irradiation unit of the present invention.

[0137] As a specific configuration example, there is a plasma irradiation unit equipped with a first electrode 9, a second electrode 10, an irradiation port 12, and a gas supply mechanism 7 (gas supply section), in which the second electrode 10 is arranged at a distance from the first electrode 9 so as to form a flow path FP for a mixed gas in which a raw material gas serving as the raw material for plasma gas PG is mixed with a reactive gas between the second electrode 10 and the first electrode 9.

[0138] The irradiation port 12 irradiates a plasma gas PG, which is generated by applying a voltage to the mixed gas flowing through the flow path FP by the first electrode 9 and the second electrode 10, toward the workpiece W (target object).

[0139] The gas supply mechanism 7 mixes the raw material gas with a reactive gas to generate a mixed gas, and supplies the mixed gas to the flow path FP. The gas supply mechanism 7 also forms a flow path for the raw material gas, and has an intake port 28 that communicates with a negative pressure region NA where negative pressure is generated by the flow of the raw material gas, and draws in the reactive gas from the intake port 28.

[0140] Any plasma irradiation unit having such a configuration can be configured as one embodiment of the plasma irradiation unit according to the present invention. For example, the dielectric member 11 of the plasma irradiation unit 2 shown in FIG. 2 is configured as a holding member that holds the second electrode 10 using a material different from the dielectric material. Then, the second electrode 10 is disposed on the inner peripheral surface (the surface facing the first electrode 9) of the holding member. For example, such a configuration makes it possible to realize a plasma irradiation unit of a type different from the dielectric barrier type. Of course, the present invention is not limited to such a configuration.

[0141] 3 and 4, a configuration having a Venturi tube 27 as the gas mixing piping section 17 constituting the gas supply mechanism 7 has been described. The gas supply section (gas supply mechanism 7) according to the present invention is not necessarily limited to a configuration having a Venturi tube. Any configuration not having a Venturi tube 27 can be adopted as long as it forms a flow path for the raw material gas, has an intake port 28 communicating with a negative pressure region NA where negative pressure is generated by the flow of the raw material gas, and is capable of generating a mixed gas by sucking in a reactive gas from the intake port 28. That is, any configuration capable of generating a mixed gas by mixing a reactive gas with a raw material gas by the so-called Venturi effect or ejector effect can be adopted (including a configuration not having a Venturi tube 27).

[0142] Fig. 6 is a schematic diagram showing a configuration example of a plasma irradiation device according to another embodiment of the present invention. In the plasma irradiation device 37 shown in Fig. 6, a static mixer 38 is arranged in the mixed gas inlet pipe 23 of the mixed gas pipe section 18. The static mixer 38 can further improve the uniformity of the mixed gas. For example, a configuration in which the static mixer 38 is arranged instead of the diffuser section of the Venturi tube 27 is also possible.

[0143] Fig. 7 is a schematic diagram showing a configuration example of a plasma irradiation head according to another embodiment of the present invention. In the plasma irradiation head 6 illustrated in Fig. 1 and Fig. 2, the irradiation port 12 is formed in a slit shape extending in the width direction (Y direction). Then, the plasma gas PG is irradiated in a line shape to the workpiece W.

[0144] The present invention is not limited to such a configuration in which the plasma gas PG is irradiated in a line shape, and it is also possible to practice the present invention using a spot-type plasma irradiation head 40 as shown in FIG.

[0145] As shown in Fig. 7, the spot-type plasma irradiation head 40 has a main body 41, a first electrode 9, and a second electrode 10. The main body 41 has a hollow cylindrical shape, and an upper end and a lower end are open. The main body 41 is disposed so that the central axis of the circular shape extends in the vertical direction (Z direction).

[0146] The first electrode 9 is a rod-shaped electrode extending in one direction, and is disposed at the central axis of the main body 41. Therefore, the first electrode 9 is disposed so as to extend in the vertical direction (Z direction). The second electrode 10 is disposed on the cylindrical inner peripheral surface of the main body 41 at a distance from the first electrode 9. In FIG. 7, the first electrode 9 disposed within the main body 41 is illustrated by a solid line to facilitate understanding of the configuration.

[0147] The gap between the first electrode 9 and the second electrode 10 serves as a flow path FP for the mixed gas supplied from the gas supply mechanism 7. The opening on the upper side of the main body 41 serves as a supply port 13 through which the mixed gas supplied from the gas supply mechanism 7 is supplied to the flow path FP formed between the second electrode 10 and the dielectric member 11. The opening on the lower side of the main body 41 serves as an irradiation port 12 through which the plasma gas PG is irradiated toward the workpiece W, which is the target object.

[0148] A voltage is applied to the mixed gas flowing through a flow path FP formed between the first electrode 9 and the second electrode. The application of the voltage causes the mixed gas to become plasma, generating a plasma gas PG. The generated plasma gas PG is irradiated toward the workpiece W from the irradiation port 12. The plasma gas PG is irradiated toward the workpiece W in a spot shape.

[0149] A gas supply unit (gas supply mechanism 7) according to the present invention can be applied as a mechanism for supplying a mixed gas in which a raw material gas is mixed with a reactive gas to the supply port 13 of such a plasma irradiation head 40. That is, a gas supply unit that configures a flow path of the raw material gas, has a suction port communicating with a negative pressure region in which negative pressure is generated by the flow of the raw material gas, and sucks in the reactive gas from the suction port can be applied. As a result, it is possible to realize one embodiment of the plasma irradiation unit and plasma irradiation device according to the present invention.

[0150] By using the spot-type plasma irradiation head 40, it becomes possible to locally irradiate the plasma gas PG to the workpiece W, and it becomes possible to realize processing by high-density plasma. On the other hand, when the plasma irradiation head 6 shown in FIG. 1 is used, it becomes possible to irradiate a large area of ​​the workpiece W with the plasma gas PG.

[0151] The plasma irradiation unit using the plasma irradiation head 40 shown in Fig. 7 can be said to be an example of a plasma irradiation unit of a type other than the dielectric barrier discharge type. On the other hand, by disposing a dielectric member 11 between the first electrode 9 and the second electrode 10 of the plasma irradiation unit 40 shown in Fig. 7, it is also possible to realize a spot-type plasma irradiation unit of the dielectric barrier discharge type.

[0152] The plasma irradiation device, plasma irradiation unit, piping, Venturi tube, and other configurations, plasma gas generation method, plasma gas irradiation method, and the like described with reference to the drawings are merely one embodiment, and may be modified as desired without departing from the spirit of the present invention. In other words, any other configuration, processing flow, algorithm, and the like for implementing the present invention may be adopted.

[0153] In this disclosure, in order to facilitate understanding of the explanation, the words "approximately", "almost", "approximately", etc. are used as appropriate. However, there is no clear difference between using the words "approximately", "almost", "approximately", etc. and not using them. In other words, in the present disclosure, concepts that define shape, size, positional relationship, state, and the like, such as "center," "central," "uniform," "equal," "same," "orthogonal," "parallel," "symmetric," "extending," "axial direction," "cylindrical," "cylindrical," "ring-shaped," and "annular," are concepts that include "substantially central," "substantially central," "substantially uniform," "substantially equal," "substantially the same," "substantially orthogonal," "substantially parallel," "substantially symmetric," "substantially extending," "substantially axial direction," "substantially cylindrical," "substantially cylindrical," "substantially ring-shaped," "substantially annular," and the like. For example, this includes states that are included within a specified range (e.g., a range of ±10%) based on standards such as "perfectly centered," "perfectly central," "perfectly uniform," "perfectly equal," "perfectly the same," "perfectly orthogonal," "perfectly parallel," "perfectly symmetrical," "perfectly extended," "perfectly axial," "perfectly cylindrical," "perfectly cylindrical," "perfectly ring-shaped," "perfectly toric," etc. Therefore, even if the words "approximately", "almost", "roughly", etc. are not added, the concept expressed by adding "approximately", "almost", "approximately", etc. may be included. Conversely, a state expressed by adding "approximately", "almost", "approximately", etc. does not necessarily exclude a perfect state.

[0154] In this disclosure, expressions using "more than", such as "greater than A" and "smaller than A", are expressions that comprehensively include both concepts that include equivalent to A and concepts that do not include equivalent to A. For example, "greater than A" is not limited to cases that do not include equivalent to A, but also includes "A or greater." Furthermore, "smaller than A" is not limited to "less than A" but also includes "A or less." When implementing the present technology, specific settings and the like may be appropriately adopted from the concepts included in "greater than A" and "smaller than A" so as to achieve the effects described above.

[0155] It is also possible to combine at least two of the characteristic parts of the present technology described above. That is, the various characteristic parts described in each embodiment may be arbitrarily combined without distinction between the embodiments. In addition, the various effects described above are merely examples and are not limited thereto, and other effects may be exhibited. [Explanation of symbols]

[0156] FP…Flow path NA: Negative pressure region PG: Plasma gas W…Work 1, 37...Plasma irradiation device 2. Plasma irradiation unit 3...Retention mechanism 4...Transport mechanism 6, 40…Plasma irradiation head 7. Gas supply mechanism 8…Voltage application mechanism 9...First electrode 10...Second electrode 11...Dielectric member 15…Source gas piping section 16…Reactive gas piping section 17...Gas mixing piping section 18...Mixed gas piping section 20, 22...Flow rate adjustment section 27…Venturi tube 28...Suction port 29…Inlet 30…Outlet 31…Nozzle section 32…Throat section 33…Diffuser section 38...Static mixer

Claims

1. A first electrode; a second electrode disposed at a distance from the first electrode so as to define a flow path for a mixed gas in which a raw material gas serving as a raw material for a plasma gas and a reactive gas are mixed between the first electrode and the second electrode; an irradiation port that irradiates a plasma gas generated by applying a voltage to the mixed gas flowing through the flow path by the first electrode and the second electrode toward a target; a gas supply unit that mixes the source gas with the reactive gas to generate the mixed gas and supplies the mixed gas to the flow path; Equipped with The gas supply unit forms a flow path of the source gas, has a suction port communicating with a negative pressure region where negative pressure is generated by the flow of the source gas, and draws in the reactive gas from the suction port. Plasma irradiation unit.

2. The plasma irradiation unit according to claim 1, further comprising: a dielectric member disposed between the first electrode and the second electrode and defining a flow path for the mixed gas between at least one of the first electrode and the second electrode; The plasma gas is generated by applying a voltage to the mixed gas flowing through the flow passage by the first electrode and the second electrode through the dielectric member. Plasma irradiation unit.

3. The plasma irradiation unit according to claim 1 or 2, The gas supply unit includes a Venturi tube. The Venturi tube forms a flow path for the source gas, has the suction port communicating with the negative pressure region, and draws in the reactive gas from the suction port. Plasma irradiation unit.

4. The plasma irradiation unit according to claim 1, The gas supply unit has a flow rate adjustment unit that adjusts the flow rate of the reactive gas supplied to the suction port. Plasma irradiation unit.

5. The plasma irradiation unit according to claim 3, the Venturi tube has an inlet through which the raw material gas flows in, an outlet through which the mixed gas flows out, and a nozzle portion that is formed between the inlet and the outlet and has a flow path cross-sectional area that decreases along a flow direction of the raw material gas, The suction port is in communication with the negative pressure region including the end of the nozzle portion on the outlet side. Plasma irradiation unit.

6. The plasma irradiation unit according to claim 3, The gas supply unit has a diffuser unit configured between the nozzle unit and the outlet port. Plasma irradiation unit.

7. The plasma irradiation unit according to claim 1, The source gas is nitrogen gas, helium gas, argon gas, carbon dioxide gas, or any combination of these gases. Plasma irradiation unit.

8. The plasma irradiation unit according to claim 1, The reactive gas is air, oxygen gas, hydrogen gas, water vapor, hydrogen peroxide gas, organic gas, ammonia gas, or a mixture of these gases in any combination. Plasma irradiation unit.

9. The plasma irradiation unit according to claim 1, The reactive gas is air. Plasma irradiation unit.

10. The plasma irradiation unit according to claim 3, The flow rate of the raw material gas flowing into the inlet is 10 L / min or more. Plasma irradiation unit.

11. The plasma irradiation unit according to claim 1, The flow rate of the raw material gas contained in the mixed gas supplied to the flow passage is 10 L / min or more. Plasma irradiation unit.

12. The plasma irradiation unit according to claim 3, The flow rate of the reactive gas supplied to the suction port is equal to or lower than the flow rate of the source gas flowing into the inlet. Plasma irradiation unit.

13. The plasma irradiation unit according to claim 1, The flow rate of the reactive gas contained in the mixed gas supplied to the flow passage is equal to or less than the flow rate of the raw material gas contained in the mixed gas supplied to the flow passage. Plasma irradiation unit.

14. The plasma irradiation unit according to claim 1, The composition ratio of the reactive gas contained in the mixed gas supplied to the flow path is equal to or lower than the composition ratio of the raw material gas contained in the mixed gas supplied to the flow path. Plasma irradiation unit.

15. The plasma irradiation unit according to claim 3, The gas supply unit includes an ejector pump having the Venturi tube. Plasma irradiation unit.

16. The plasma irradiation unit according to claim 1, The object is a carbon fiber reinforced plastic. Plasma irradiation unit.

17. A plasma irradiation device comprising the plasma irradiation unit according to claim 1, further comprising: The plasma irradiation unit includes a holding mechanism for holding an object to be irradiated with plasma gas by the plasma irradiation unit. Plasma irradiation device.

18. The plasma irradiation device according to claim 13, further comprising: a transport mechanism for transporting the object held by the holding mechanism relative to the plasma irradiation unit; Plasma irradiation device.

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