Plasma generating device and plasma processing method

Abstract

The plasma generating device comprises: a device body, which forms a reaction chamber for plasmatizing a processing gas; at least one exhaust passage connected to the reaction chamber; a diffusion chamber connected to the at least one exhaust passage; and a plurality of ejection passages connected to the diffusion chamber and ejecting the plasma gas that has been plasmatized in the reaction chamber, wherein at least one of the plurality of ejection passages has a tapered surface formed at its opening toward the diffusion chamber.

Description

Technical Field

[0001] The present invention relates to a plasma generating device and the like which ejects plasma gas from an ejection passage. Background Art

[0002] Some plasma generating devices are configured to convert a processing gas into plasma in a reaction chamber and eject the converted plasma gas from an ejection passage formed in a nozzle. An example of such a plasma generating device is described in the following patent document.

[0003] Prior art literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2001-068298 Summary of the invention

[0005] Problems to be solved by the invention

[0006] An object of the present specification is to improve the practicality of a plasma generating device having a structure for ejecting plasma gas from an ejection passage.

[0007] Technical solutions to solve problems

[0008] In order to solve the above-mentioned problems, the present specification discloses a plasma generating device, which comprises: a device body, which forms a reaction chamber for plasmatizing a processing gas; at least one exhaust passage connected to the above-mentioned reaction chamber; a diffusion chamber connected to the above-mentioned at least one exhaust passage; and a plurality of ejection passages connected to the above-mentioned diffusion chamber and ejecting the plasma gas which is plasmatized in the above-mentioned reaction chamber, wherein a conical surface is formed at the opening of at least one ejection passage among the above-mentioned plurality of ejection passages toward the above-mentioned diffusion chamber.

[0009] In addition, the present specification discloses a plasma generating device, comprising: a device body, which forms a reaction chamber for plasmatizing a processing gas; and a nozzle, which is installed on the above-mentioned device body and ejects plasma gas that is plasmatized in the above-mentioned reaction chamber, the above-mentioned device body has an exhaust passage for exhausting the plasma gas that is plasmatized in the above-mentioned reaction chamber to the outside of the above-mentioned device body, and the above-mentioned nozzle has: a diffusion chamber, which is formed as an opening of the outer wall surface of the above-mentioned device body that covers the above-mentioned exhaust passage; and multiple ejection passages, which are used to eject plasma gas through the above-mentioned diffusion chamber, the above-mentioned multiple ejection passages eject the plasma gas that is plasmatized in the above-mentioned reaction chamber, and the opening of one or more of the above-mentioned multiple ejection passages facing the above-mentioned diffusion chamber is formed with a tapered surface.

[0010] In addition, the present specification discloses a plasma processing method, which is used for a plasma generating device, wherein the plasma generating device comprises: a device body, which forms a reaction chamber for plasmatizing a processing gas; and a nozzle, which is installed on the device body and ejects plasma gas which is plasmatized in the reaction chamber, wherein the device body has an exhaust passage for exhausting the plasma gas which is plasmatized in the reaction chamber to the outside of the device body, and the nozzle comprises: a diffusion chamber, which is formed as an opening of the outer wall surface of the device body which covers the exhaust passage; and a plurality of ejection passages, which are used to eject plasma gas through the diffusion chamber, wherein the plurality of ejection passages eject the plasma gas which is plasmatized in the reaction chamber, and a tapered surface is formed at the opening of at least one of the plurality of ejection passages which faces the diffusion chamber, and the plasma processing method irradiates the plasma gas ejected from the plurality of ejection passages onto a processed object.

[0011] Effects of the Invention

[0012] According to the present disclosure, by forming a tapered surface at the opening of the ejection passage toward the diffusion chamber, for example, even if foreign matter is attached to the opening, the opening is not easily blocked by the foreign matter. Thus, the ejection of plasma gas from the ejection passage can be ensured, and the practicality of the plasma generating device having a structure for ejecting plasma gas from the ejection passage can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a diagram showing a plasma device.

[0014] Figure 2 It is a perspective view showing a plasma head.

[0015] Figure 3 This is a cross-sectional view of the plasma head cut in the X direction and the Z direction at the positions of the electrode and the plasma passage on the main body side.

[0016] Figure 4 yes Figure 3 Section view at line AA in the figure.

[0017] Figure 5 yes Figure 3 Enlarged cross-sectional view of .

[0018] Figure 6 Is installed with Figure 3 Nozzles. Cross-sectional views of plasma heads with different nozzles. DETAILED DESCRIPTION

[0019] Hereinafter, as a mode for carrying out the present invention, an embodiment of the present invention will be described in detail with reference to the drawings.

[0020] like Figure 1 As shown, the plasma device 10 includes a plasma head 11, a robot 13, and a control box 15. The plasma head 11 is mounted on the robot 13. The robot 13 is, for example, a serial link type robot (also called a multi-jointed robot). The plasma head 11 can irradiate plasma gas while being held at the front end of the robot 13. The plasma head 11 can move three-dimensionally according to the drive of the robot 13.

[0021] The control box 15 is mainly composed of a computer and generally controls the plasma device 10. The control box 15 includes a power supply unit 15A for supplying power to the plasma head 11 and a gas supply unit 15B for supplying gas to the plasma head 11. The power supply unit 15A is connected to the plasma head 11 via a power cable (not shown). The power supply unit 15A changes the electrode 33 (see FIG. 1 ) of the plasma head 11 based on the control of the control box 15. Figure 3 and Figure 4 ) applied voltage.

[0022] In addition, the gas supply unit 15B is connected to the plasma head 11 via a plurality of (four in the present embodiment) gas hoses 19. The gas supply unit 15B supplies the reaction gas, carrier gas, and hot gas described later to the plasma head 11 based on the control of the control box 15. The control box 15 controls the gas supply unit 15B to control the amount of gas supplied from the gas supply unit 15B to the plasma head 11. Thus, the robot 13 operates based on the control of the control box 15, and irradiates the plasma gas from the plasma head 11 to the object to be processed W placed on the workbench 17.

[0023] In addition, the control box 15 includes an operation unit 15C, and the operation unit 15C includes a touch panel and various switches. The control box 15 displays various setting screens and operation states (for example, gas supply state, etc.) on the touch panel of the operation unit 15C. In addition, the control box 15 receives various information through operation input to the operation unit 15C.

[0024] like Figure 2 As shown, the plasma head 11 includes a plasma generating unit 21, a hot gas supply unit 23, and the like. The plasma generating unit 21 supplies gas from a gas supply unit 15B (see Figure 1 ) is converted into plasma to generate plasma gas. The hot gas supply unit 23 heats the gas supplied from the gas supply unit 15B to generate hot gas. The plasma head 11 of this embodiment transmits the plasma gas generated in the plasma generating unit 21 together with the hot gas generated by the hot gas supply unit 23 to the plasma head 11. Figure 1 The treated object W is ejected as shown. In the plasma head 11, along Figure 2The processing gas is supplied from the upstream side to the downstream side in the direction of the arrow shown. In addition, the plasma head 11 may be configured not to include the hot gas supply unit 23. That is, the plasma apparatus of the present disclosure may be configured not to use hot gas.

[0025] like Figure 3 and Figure 4 As shown, the plasma generating unit 21 includes a head main body 31, a pair of electrodes 33, a plasma irradiation unit 35, etc. Figure 3 2 is a cross-sectional view obtained by cutting the pair of electrodes 33 and a plurality of main body side plasma passages 71 described later so as to be aligned with each other. Figure 4 yes Figure 3 sectional view at line AA in FIG. The head body 31 is formed of ceramic having high heat resistance, and a reaction chamber 37 for generating plasma gas is formed inside the head body 31. A pair of electrodes 33 are each in the shape of a cylinder, for example, and are fixed in a state where the front end thereof protrudes toward the reaction chamber 37. In the following description, there is a case where the pair of electrodes 33 are simply referred to as electrodes 33. In addition, the direction in which the pair of electrodes 33 are arranged is referred to as the X direction, the direction in which the plasma generating section 21 and the hot gas supply section 23 are arranged is referred to as the Y direction, and the axial direction of the cylindrical electrode 33 is referred to as the Z direction for description. In addition, in the present embodiment, the X direction, the Y direction, and the Z direction are mutually orthogonal directions.

[0026] The hot gas supply unit 23 includes a gas pipe 41, a heater 43, a connecting portion 45, etc. The gas pipe 41 and the heater 43 are mounted on the outer peripheral surface of the head body 31 and are Figure 4 The gas pipe 41 is covered by the cover 47 shown. Figure 1 ) and connected to the gas supply unit 15B of the control box 15. Gas (for example, air) is supplied from the gas supply unit 15B to the gas pipe 41. The heater 43 is installed in the middle of the gas pipe 41. The heater 43 heats the gas flowing in the gas pipe 41 to generate hot gas.

[0027] like Figure 4 As shown, the connecting portion 45 connects the gas pipe 41 and the plasma irradiation portion 35. When the plasma irradiation portion 35 is mounted on the head body 31, one end of the connecting portion 45 is connected to the gas pipe 41, and the other end is connected to the hot gas passage 51 formed in the plasma irradiation portion 35. Hot gas is supplied to the hot gas passage 51 via the gas pipe 41.

[0028] like Figure 4As shown, a part of the outer periphery of the electrode 33 is covered by an electrode cover 53 made of an insulator such as ceramic. The electrode cover 53 is roughly hollow and cylindrical, and openings are formed at both ends in the length direction. The gap between the inner peripheral surface of the electrode cover 53 and the outer peripheral surface of the electrode 33 functions as a gas passage 55. The opening on the downstream side of the electrode cover 53 is connected to the reaction chamber 37. The lower end of the electrode 33 protrudes from the opening on the downstream side of the electrode cover 53.

[0029] In addition, a reaction gas flow path 61 and a pair of carrier gas flow paths 63 are formed inside the head body 31. The reaction gas flow path 61 is provided at a substantially central portion of the head body 31 and is connected to the head body 31 via a gas hose 19 (see Figure 1 ) and connected to the gas supply unit 15B, so that the reaction gas supplied from the gas supply unit 15B flows into the reaction chamber 37. In addition, a pair of carrier gas flow paths 63 are arranged in the X direction at a position sandwiching the reaction gas flow path 61. The pair of carrier gas flow paths 63 are each connected via a gas hose 19 (see Figure 1 ) is connected to the gas supply unit 15B, and the carrier gas is supplied from the gas supply unit 15B. The carrier gas flow path 63 allows the carrier gas to flow into the reaction chamber 37 through the gas passage 55.

[0030] As a reaction gas (seed gas), oxygen (O2) can be used. The gas supply unit 15B, for example, flows a mixed gas of oxygen and nitrogen (N2) (e.g., dry air (Air)) into between the electrodes 33 of the reaction chamber 37 via the reaction gas flow path 61. Hereinafter, for convenience, there is a case where the mixed gas is referred to as a reaction gas and oxygen is referred to as a seed gas. As a carrier gas, nitrogen can be used. The gas supply unit 15B flows a carrier gas from each gas passage 55 in a manner that surrounds each electrode 33 in a pair of electrodes 33.

[0031] An alternating voltage is applied to the pair of electrodes 33 from the power supply unit 15A of the control box 15. By applying the voltage, for example, Figure 4 As shown, a pseudo arc A is generated between the lower ends of a pair of electrodes 33 in the reaction chamber 37. The reaction gas is plasmatized when passing through the pseudo arc A. Therefore, the pair of electrodes 33 generate discharge of the pseudo arc A, and the reaction gas is plasmatized to generate plasma gas.

[0032] In addition, a plurality of (six in this embodiment) main body side plasma passages 71 are formed in the downstream portion of the reaction chamber 37 in the head main body 31, arranged at intervals in the X direction and extending in the Z direction. The ends of the upstream side of the plurality of main body side plasma passages 71 open in the reaction chamber 37, and the ends of the downstream side of the plurality of main body side plasma passages 71 open in the lower end surface of the head main body 31.

[0033] The plasma irradiation section 35 includes a nozzle 73, a nozzle cover 75, and the like. The nozzle 73 is roughly T-shaped when viewed from the side in the X direction, and is composed of a nozzle body 77 and a nozzle front end 79. In addition, the nozzle 73 is an integral body composed of the nozzle body 77 and the nozzle front end 79, and is formed of ceramic with high heat resistance. The nozzle body 77 is roughly flange-shaped and is fixed to the lower surface of the head body 31 by bolts 80. Therefore, the nozzle 73 can be detached from the head body 31 and can be changed to a different type of nozzle. In addition, the nozzle front end 79 is formed in a shape extending downward from the lower surface of the nozzle body 77.

[0034] A pair of grooves 81 opening at the upper end surface of the nozzle body 77 is formed on the nozzle 73. The pair of grooves 81 are arranged in a row in a manner extending along the X direction, and when the nozzle 73 is mounted on the head body 31, the three main body side plasma passages 71 opening at the lower end surface of the head body 31 are connected to each of the pair of grooves 81. That is, the openings at the lower ends of three main body side plasma passages 71 out of the six main body side plasma passages 71 are connected to one of the pair of grooves 81, and the openings at the lower ends of the remaining three main body side plasma passages 71 are connected to the other of the pair of grooves 81.

[0035] In addition, a plurality of (10 in this embodiment) nozzle side plasma passages 82 are formed in the nozzle 73, penetrating the nozzle body 77 and the nozzle front end 79 in the vertical direction, that is, the Z direction, and these plurality of nozzle side plasma passages 82 are arranged at intervals in the X direction. In addition, the upper ends of five of the ten nozzle side plasma passages 82 are opened at the bottom surface of one of the pair of grooves 81, and the upper ends of the remaining five nozzle side plasma passages 82 are opened at the bottom surface of the other of the pair of grooves 81.

[0036] The nozzle cover 75 is substantially T-shaped when viewed from the side in the X direction, and is composed of a cover body 85 and a cover front end 87. In addition, the nozzle cover 75 is an integral body composed of the cover body 85 and the cover front end 87, and is formed of ceramic with high heat resistance. The cover body 85 is formed in a substantially plate shape of a thick plate, and a recessed portion 89 is formed in the cover body 85, which is open on the upper surface and recessed in the Z direction. In addition, the cover body 85 is fixed to the lower surface of the head body 31 by bolts 90 in a manner that the nozzle body 77 of the nozzle 73 is accommodated in the recessed portion 89. Therefore, the nozzle cover 75 is formed to be detachable relative to the head body 31, and is removed from the head body 31 when the nozzle 73 is replaced. In addition, a hot gas passage 51 is formed in the cover body 85 in a manner extending along the Y direction, one end of the hot gas passage 51 is opened in the recessed portion 89, and the other end of the hot gas passage 51 is opened on the side of the cover body 85. Furthermore, an end portion of the hot gas passage 51 opened at the side surface of the cover body 85 is connected to the connection portion 45 of the hot gas supply portion 23 .

[0037] The cover front end 87 extends downward from the lower surface of the cover body 85. A through hole 93 is formed in the cover front end 87, which penetrates in the Z direction, and the upper end of the through hole 93 is connected to the recessed portion 89 of the cover body 85. In addition, the nozzle front end 79 of the nozzle 73 is inserted into the through hole 93. Thus, the nozzle 73 is entirely covered by the nozzle cover 75. In addition, the lower end of the nozzle front end 79 of the nozzle 73 is located at the same height as the lower end of the cover front end 87 of the nozzle cover 75.

[0038] In addition, when the nozzle 73 is covered by the nozzle cover 75, the nozzle body 77 of the nozzle 73 is located inside the recessed portion 89 of the nozzle cover 75, and the nozzle tip 79 of the nozzle 73 is located inside the through hole 93 of the nozzle cover 75. In this state, there are gaps between the recessed portion 89 and the nozzle body 77 and between the through hole 93 and the nozzle tip 79, and the gaps function as the hot gas output passage 95. Hot gas is supplied to the hot gas output passage 95 via the hot gas passage 51.

[0039] With such a structure, the plasma gas generated in the reaction chamber 37 is ejected into the inside of the groove 81 through the main body side plasma passage 71 together with the carrier gas. In addition, the plasma gas diffuses inside the groove 81, and is ejected from the opening 82A at the lower end of the nozzle side plasma passage 82 through the nozzle side plasma passage 82. In addition, the hot gas supplied from the gas pipe 41 to the hot gas passage 51 flows in the hot gas output passage 95. The hot gas functions as a protective gas for protecting the plasma gas. The hot gas flows in the hot gas output passage 95, and is ejected from the opening 95A at the lower end of the hot gas output passage 95 along the ejection direction of the plasma gas. At this time, the hot gas is ejected in a manner surrounding the plasma gas ejected from the opening 82A of the nozzle side plasma passage 82. In this way, by ejecting the heated hot gas around the plasma gas, the efficacy (wettability, etc.) of the plasma gas can be improved.

[0040] In this way, in the plasma head 11, discharge is generated in the reaction chamber 37, plasma is generated, and the plasma gas is ejected from the front end of the nozzle 73, and plasma treatment is performed on the object W. However, due to the discharge in the reaction chamber 37, the inner wall surface of the head body 31 that partitions the reaction chamber 37, the electrode 33, etc. are carbonized to generate foreign matter. When foreign matter is generated in the reaction chamber 37 in this way, the foreign matter is discharged to the groove 81 through the main body side plasma passage 71. At this time, inside the groove 81, the foreign matter adheres to and accumulates at the opening of the nozzle side plasma passage 82 that opens to the groove 81. In addition, there is a case where the foreign matter accumulated at the opening of the nozzle side plasma passage 82 blocks the opening of the nozzle side plasma passage 82. In this case, the internal pressure of the reaction chamber 37 rises, and appropriate discharge cannot be ensured. In order to prevent such a situation, the nozzle 73 is removed from the head body 31, and the opening of the nozzle side plasma passage 82 toward the inside of the groove 81 is cleaned. However, each time the cleaning is performed, the operation of the plasma head 11 needs to be stopped, resulting in a decrease in productivity.

[0041] For this purpose, in the plasma head 11, as shown in FIG. Figure 5 As shown, a tapered surface 100 is formed at the opening of the nozzle side plasma passage 82 toward the inside of the slot 81. That is, the opening of the nozzle side plasma passage 82 toward the inside of the slot 81 is chamfered, and the inner diameter of the end of the nozzle side plasma passage 82 on the opening side toward the inside of the slot 81 gradually increases. In addition, the inner diameter of the portion of the nozzle side plasma passage 82 where the tapered surface 100 is not formed is set to be uniform. In this way, by forming the tapered surface 100 at the opening of the nozzle side plasma passage 82 toward the slot 81, even if foreign matter is attached to and accumulated at the opening of the nozzle side plasma passage 82, the opening is difficult to be blocked. As a result, the cleaning frequency of the opening of the nozzle side plasma passage 82 can be reduced, and the decline in productivity can be suppressed.

[0042] In addition, in the plasma head 11, the tapered surface 100 is not formed in all of the plurality of nozzle-side plasma passages 82, but is formed in only a portion of the plurality of nozzle-side plasma passages 82. Specifically, the plasma gas generated in the reaction chamber 37 flows from the main body-side plasma passage 71 into the interior of the groove 81, and diffuses in the interior of the groove 81. Then, it flows out from the interior of the groove 81 to the plurality of nozzle-side plasma passages 82. At this time, the flow of the plasma gas is different when the plasma gas diffuses in the interior of the groove 81 and when the plasma gas flows from the groove 81 to each of the plurality of nozzle-side plasma passages 82, so it is found that foreign matter is easily retained in the portion where the vortex is generated by the flow of the plasma gas.

[0043] For this purpose, when manufacturing the nozzle 73, the flow of plasma gas in the plasma head 11 is simulated by computer analysis based on the size, number, arrangement, flow rate of plasma gas, etc. of the main body side plasma passage 71, the slot 81, the nozzle side plasma passage 82, etc. At this time, in the simulated flow of plasma gas, vortices are generated near the second and third openings from both ends in the X direction of the 10 nozzle side plasma passages 82. Therefore, the openings of the four nozzle side plasma passages 82 located second and third from both ends in the X direction of the 10 nozzle side plasma passages 82 are formed with a conical surface 100. That is, with the center of the arrangement direction of the 10 nozzle side plasma passages 82 as the center, the conical surface 100 is formed symmetrically at the openings of the four nozzle side plasma passages 82 located third and fourth from the center toward the slot 81.

[0044] In this way, the opening of the nozzle side plasma passage 82 where foreign matter is easily accumulated is enlarged by forming the tapered surface 100 at the opening of a part of the plurality of nozzle side plasma passages 82. Thus, even if foreign matter is accumulated at the opening of the nozzle side plasma passage 82 facing the groove 81 over time, the difference in the flow rate of the plasma gas between the nozzle side plasma passage 82 where foreign matter is easily accumulated and the nozzle side plasma passage 82 where foreign matter is not easily accumulated is reduced, and appropriate plasma processing can be ensured.

[0045] In addition, in the plasma head 11, as described above, the nozzle 73 can be replaced. For example, the nozzle 73 can be replaced with Figure 6The nozzle 110 shown is mounted on the head body 31. A pair of slots 112 and six nozzle-side plasma passages 114 are formed in the nozzle 110. Three of the six nozzle-side plasma passages 114 open in one of the pair of slots 112, and the remaining three nozzle-side plasma passages 114 open in the other of the pair of slots 112.

[0046] In addition, when manufacturing the nozzle 110, the flow of plasma gas in the plasma head 11 is simulated by computer analysis based on the size, number, arrangement, flow rate of plasma gas, etc. of the main body side plasma passage 71, the groove 112, the nozzle side plasma passage 114, etc. At this time, in the simulated flow of plasma gas, vortices are generated near the second opening from the two ends in the X direction among the six nozzle side plasma passages 114. Therefore, the openings of the two nozzle side plasma passages 114 located second from the two ends in the X direction among the six nozzle side plasma passages 114 are formed with a tapered surface 120 facing the groove 112. That is, with the center of the arrangement direction of the six nozzle side plasma passages 114 as the center, the tapered surface 120 is formed symmetrically at the openings of the two nozzle side plasma passages 114 located second from the center.

[0047] In this way, according to the type of each nozzle 73, 110, the openings of some of the nozzle side plasma paths 82, 114 are formed with tapered surfaces 100, 120. Thus, in each of the multiple nozzles 73, 110, it is possible to prevent a decrease in productivity due to accumulation of foreign matter, ensure appropriate plasma processing, etc.

[0048] Incidentally, the plasma device 10 is an example of a plasma generating device. The head body 31 is an example of a device body. The reaction chamber 37 is an example of a reaction chamber. The nozzle 73 is an example of a nozzle. The main body side plasma passage 71 is an example of an exhaust passage. The groove 81 is an example of a diffusion chamber. The nozzle side plasma passage 82 is an example of an ejection passage. The tapered surface 100 is an example of a tapered surface. The nozzle 110 is an example of a nozzle. The groove 112 is an example of a diffusion chamber. The nozzle side plasma passage 114 is an example of an ejection passage. The tapered surface 120 is an example of a tapered surface.

[0049] As described above, in the present embodiment described above, the following effects are achieved.

[0050] In the plasma head 11, tapered surfaces 100 and 120 are formed at the openings of at least one of the plurality of nozzle side plasma passages 82 and 114. This can reduce the frequency of cleaning the openings of the nozzle side plasma passages 82 and suppress a decrease in productivity.

[0051] In addition, in the plasma head 11, the tapered surfaces 100 and 120 are not formed on all of the plurality of nozzle-side plasma passages 82 and 114, but are formed on only a portion of the plurality of nozzle-side plasma passages 82 and 114. Thus, the difference in the flow rate of plasma gas can be reduced between the nozzle-side plasma passages 82 and 114 where foreign matter is easily accumulated and the nozzle-side plasma passages 82 and 114 where foreign matter is not easily accumulated, thereby ensuring appropriate plasma processing.

[0052] In the plasma head 11, the tapered surfaces 100 and 120 are formed to be symmetrically arranged around the center of the arrangement direction of the plurality of nozzle-side plasma channels 82 and 114. This can ideally suppress nozzle clogging in the plurality of nozzle-side plasma channels 82 and 114 as a whole.

[0053] In addition, in the plasma head 11, the nozzles 73 and 110 are mounted on the head body 31 in a manner that cannot be relatively moved. As a result, the plasma gas can be stably ejected toward the object W. Further, in the plasma head 11, as described above, the hot gas is ejected in a manner that surrounds the ejected plasma gas. Therefore, by mounting the nozzles 73 and 110 on the head body 31 in a manner that cannot be relatively moved, the plasma gas can be ejected in a state appropriately covered by the hot gas.

[0054] In addition, the present disclosure is not limited to the above-mentioned embodiment, and can be implemented in various forms with various changes and improvements based on the knowledge of those skilled in the art. Specifically, for example, in the plasma head 11, only a part of the nozzle side plasma passages 82, 114 among the plurality of nozzle side plasma passages 82, 114 are formed with the tapered surfaces 100, 120, but the tapered surfaces 100, 120 may be formed in all of the plurality of nozzle side plasma passages 82, 114.

[0055] In the above embodiment, the groove 81 is used as the diffusion chamber, but various structures such as a recess, a passage, and a partitioned space may be used as the diffusion chamber as long as the structure communicates with the main body side plasma passage 71 .

[0056] In addition, in the above embodiment, a main body side plasma passage 71 is formed in the head main body 31, and a groove 81 and a nozzle side plasma passage 82 are formed in the nozzle 73, but a main body side plasma passage 71 and a groove 81 may be formed in the head main body 31, and a nozzle side plasma passage 82 may be formed in the nozzle 73.

[0057] In the above embodiment, the head body 31 and the nozzle 73 are detachably formed, but the head body 31 and the nozzle 73 may be formed integrally. In other words, the reaction chamber 37, the main body side plasma passage 71, the groove 81 and the nozzle side plasma passage 82 may be formed inside the integrated device body.

[0058] In addition, in the plasma head 11, the flow of plasma gas is simulated, and the nozzle side plasma passage forming the tapered surface is determined based on the simulated flow of plasma gas, but the nozzle side plasma passage forming the tapered surface may also be determined based on other methods. For example, the nozzle side plasma passage at the position where foreign matter is likely to accumulate may also be determined as the nozzle side plasma passage forming the tapered surface based on empirical rules.

[0059] Description of Reference Numerals

[0060] 10. Plasma device (plasma generating device); 31. Head body (device body); 37. Reaction chamber; 71. Main body side plasma passage (exhaust passage); 73. Nozzle; 81. Groove (diffusion chamber); 82. Nozzle side plasma passage (ejection passage); 100. Conical surface; 110. Nozzle; 112. Groove (diffusion chamber); 114. Nozzle side plasma passage (ejection passage); 120. Conical surface.

Claims

1. A plasma generating device, comprising: The device body is formed with a reaction chamber for converting the processing gas into plasma; and A nozzle is installed in the device body and ejects the plasma gas converted into plasma in the reaction chamber. The device body has an exhaust passage for exhausting the plasma gas converted into plasma in the reaction chamber to the outside of the device body. The nozzle has: a diffusion chamber formed to cover an opening of the exhaust passage toward an outer wall surface of the device body; and A plurality of ejection passages are used to eject plasma gas through the diffusion chamber, wherein the plurality of ejection passages eject the plasma gas converted into plasma in the reaction chamber, and a tapered surface is formed at an opening of at least one of the plurality of ejection passages toward the diffusion chamber so that the inner diameter of the end of the opening side of the at least one ejection passage toward the inside of the diffusion chamber gradually increases. The tapered surface is not formed on the openings of all the plurality of ejection passages facing the diffusion chamber, but is formed on the openings of some of the plurality of ejection passages facing the diffusion chamber. A plurality of ejection passages are formed in a row in the nozzle. The tapered surface is formed symmetrically about the center of the plurality of ejection passages in a row according to the type of the nozzle, at an opening of the portion of the ejection passages where a vortex is generated by the flow of the plasma gas and faces the diffusion chamber.

2. The plasma generating device according to claim 1, wherein: The nozzle is mounted on the device body in a relatively non-movable manner.

3. A plasma treatment method, used in a plasma generating device, The plasma generating device comprises: The device body is formed with a reaction chamber for converting the processing gas into plasma; and A nozzle is installed in the device body and ejects the plasma gas converted into plasma in the reaction chamber. The device body has an exhaust passage for exhausting the plasma gas converted into plasma in the reaction chamber to the outside of the device body. The nozzle has: a diffusion chamber formed to cover an opening of the exhaust passage toward an outer wall surface of the device body; and A plurality of ejection passages are provided for ejecting plasma gas through the diffusion chamber, wherein the plurality of ejection passages eject plasma gas converted to plasma in the reaction chamber, and a tapered surface is formed at the opening of at least one of the plurality of ejection passages facing the diffusion chamber so that the inner diameter of the end of the opening side of the at least one ejection passage facing the inside of the diffusion chamber gradually increases. The tapered surface is not formed at the opening of all of the plurality of ejection passages facing the diffusion chamber, but is formed at the opening of a portion of the plurality of ejection passages facing the diffusion chamber. The plurality of ejection passages are formed in a row in the nozzle, and the tapered surface is symmetrically formed at the opening of the portion of the ejection passages facing the diffusion chamber where a vortex is generated by the flow of the plasma gas, depending on the type of the nozzle, with the center of the direction in which the plurality of ejection passages are arranged in a row as the center. The plasma processing method irradiates a processing target object with plasma gas ejected from the plurality of ejection paths.

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