JP2007273096A - Plasma generator and workpiece processing apparatus using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma generator used for processing of a workpiece, such as reforming of a substrate and the like, which performing plasma (bloom) lighting surely and immediately. <P>SOLUTION: In a plasma generating nozzle 31, a lower end portion 322 of a center conductor 32 is formed of an outer pipe portion 3221 and an inner pipe portion 3222 freely lengthened and shortened in collapsible manner. With an electromagnetic solenoid 38, at the time of plasma ignition, a tip surface 3222c of a lower end portion 3222a of the inner tube portion 3222 moves back rather than the lower end edge 331 of a nozzle body 33 and at the time of normal lighting, the tip surface 322c of the lower end portion 322a of the inner tube portion 3222 projects rather than the lower end edge 331 of the nozzle body 33. Thus, the processed gas passes through around the lower end portion 322a and around the lower end edge 331 which electric field converges, and therefore easily changes itself into molecule, atom and plasma in order, thereby performing plasma (bloom) lighting surely and immediately. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a plasma generator capable of purifying or modifying the surface of a workpiece by irradiating plasma on a workpiece to be processed such as a substrate, and a workpiece processing apparatus using the plasma generator.

For example, there is known a workpiece processing apparatus that irradiates a workpiece to be processed such as a semiconductor substrate with plasma and removes organic contaminants on the surface, surface modification, etching, thin film formation, or thin film removal. For example, Patent Document 1 uses a plasma generation nozzle having concentric inner conductors and outer conductors, and applies a high-frequency pulse electric field between the two conductors, thereby generating glow discharge instead of arc discharge. The plasma is generated, and a high-density plasma is generated by turning the processing gas from the gas supply source from the base end side to the free end side while swirling between both conductors, and is attached to the free end. A plasma processing apparatus is disclosed in which high-density plasma can be obtained under normal pressure by radiating a workpiece to be processed from a nozzle.
JP 2003-197397 A

  The above-described prior art is an excellent plasma processing apparatus capable of obtaining high-density plasma under normal pressure. However, there is room for improvement in the ignitability of the plasma (plume). Specifically, if the power of the microwave is increased to improve the ignitability, the power becomes excessive during steady lighting, the stability is poor for continuous lighting, and the power consumption increases. There exists a problem that the lifetime of a microwave generator becomes short. In particular, when a plurality of plasma generating nozzles are driven by one microwave generating means, there is a slight difference in the intensity of microwaves received by the inner conductor of each plasma generating nozzle, or there is a difference in gas flow rate. Therefore, there are many differences in ease of plasma ignition. In that case, it is difficult to perform plasma (plume) ignition reliably and promptly.

  An object of the present invention is to provide a plasma generator capable of performing plasma (plume) ignition reliably and promptly and a workpiece processing apparatus using the plasma generator.

  The plasma generating apparatus of the present invention uses a plasma generating nozzle having concentric inner conductors and outer conductors, and applies a high-frequency pulse electric field between the two conductors, so that the vicinity of the tips of both conductors. A plasma generator that generates plasma by generating glow discharge and supplying a processing gas from a gas supply source between them to radiate plasma gas from the nozzle of the outlet under normal pressure to the workpiece. The method further includes ignition assisting means for retreating the front end surface of the inner conductor relative to the front end surface of the outer conductor relatively during plasma ignition.

  According to the above configuration, in the plasma generation apparatus that can be used for workpiece processing such as substrate modification, the plasma generation nozzle has concentric inner conductors and outer conductors, and a space between them. By applying a high-frequency pulsed electric field to the plasma, a glow discharge is generated instead of an arc discharge to generate plasma, and further, a processing gas from a gas supply source is supplied between them, so that the nozzle of the outlet port In a plasma generator configured to radiate plasma gas under normal pressure to a workpiece, the inner conductor can be moved in and out in the axial direction, that is, in the plasma blowing direction, in the nozzle of the blowing port. Alternatively, the outer conductor is configured to be extendable and retracted, and at the time of plasma ignition, the tip surface of the inner conductor is moved backward relative to the tip surface of the outer conductor. Provision of the ignition auxiliary means. When the light is extinguished, the positional relationship between the inner conductor and the outer conductor is arbitrary, and at the time of steady lighting, the tip surface of the inner conductor is aligned with, or preferably protruded from, the tip surface of the outer conductor. Good.

  Therefore, the process gas passes from the vicinity of the tip portion of the inner conductor where the electric field is concentrated to the vicinity of the tip portion of the outer conductor with the flow, and thus changes from molecule to atom to plasma. Easy, reliable and quick plasma (plume) ignition can be performed.

  In the plasma generator of the present invention, the ignition assisting means causes the tip surface of the inner conductor to protrude relative to the tip surface of the outer conductor when the plasma is steadily lit.

  According to the above configuration, at the time of steady lighting, the tip of the inner conductor that is the end of the coaxial transmission line is protruded from the tip of the outer conductor, so that the tip of the inner conductor is between the tip of the outer conductor. An electric field is formed in an inner portion having a smaller impedance than the inner portion.

  Therefore, even if the size of the plasma (plume) does not change, power consumption during steady lighting can be reduced.

  Furthermore, in the plasma generator of the present invention, the inner conductor includes a collapsible outer cylinder part and an inner cylinder part that are freely retractable and retractable, and the ignition assisting means includes an operating piece that is the inner cylinder part. It consists of the electromagnetic solenoid connected with the base end side of this.

  According to the above configuration, in the simplest form with few movable parts, the front end surface of the inner conductor is moved backward with respect to the front end surface of the outer conductor at the time of plasma ignition as described above, and the outer conductor is The structure which makes the front end surface of an inner side conductor protrude with respect to a front end surface is realizable.

  Further, in the plasma generator of the present invention, the distal end portion of the outer conductor is formed by being separated into an outer tube portion and a retractable inner tube portion that can be retracted and retracted in the outer tube portion, The ignition assisting means includes an electromagnetic solenoid having an operating piece connected to the inner cylinder portion.

  According to the above configuration, although the movable part is somewhat larger, the outer diameter of the inner conductor and the inner diameter of the outer conductor, that is, the configuration with the smallest impedance change, the front end surface of the inner conductor at the time of plasma ignition as described above On the other hand, it is possible to realize a configuration in which the front end surface of the outer conductor is protruded and the front end surface of the outer conductor is retreated with respect to the front end surface of the inner conductor during steady lighting.

  Furthermore, in the plasma generator of the present invention, the microwave from the microwave generating means is propagated by the waveguide and received by the inner conductor of the plasma generating nozzle protruding into the waveguide space, and the inner conductor is It is held between the outer conductor by an electrically insulating seal member, and the seal member is formed to be slidable in the cylindrical axial direction between the inner peripheral surface of the cylindrical outer conductor, The ignition assisting means includes an electromagnetic solenoid having an operating piece connected to the seal member.

  According to the above configuration, when the microwave from the microwave generating means is propagated by the waveguide and received by the inner conductor of the plasma generating nozzle, the inner conductor is held between the outer conductor. An electrically insulating seal member is formed so as to be slidable in the axial direction between the inner peripheral surface of the cylindrical outer conductor, and an operating piece of an electromagnetic solenoid serving as the ignition auxiliary means is connected to the seal member. For each of the seal members, the tip of the inner conductor is retracted from the tip of the outer conductor during ignition, and protrudes from the tip of the outer conductor during steady lighting.

  Therefore, the portion of the inner conductor that becomes the receiving antenna portion on the side of the waveguide with respect to the seal member protrudes with respect to the waveguide space during ignition and retreats during steady lighting. This increases the reception microwave energy of the reception antenna unit at the time of ignition, making it easier to ignite.

  In the plasma generating apparatus of the present invention, the microwave from the microwave generating means is propagated by the waveguide, and a plurality of the plasma generating nozzles are arranged and attached in the waveguide of the plasma generating unit. Features.

  According to the above configuration, the microwave generated by the microwave generating means is propagated through the waveguide, and a plurality of the plasma generating nozzles are arranged and attached to the waveguide in the plasma generating unit. In the plasma generator configured as described above, the microwaves from the microwave generating means are sequentially captured by the inner conductors of the plurality of plasma generating nozzles arranged in the waveguide and used for plasma generation.

  Therefore, by improving the ignitability of each plasma generating nozzle, for many plasma generating nozzles, it is possible to use the microwave generating means corresponding to the substantially maximum power during steady lighting, The means can be miniaturized and the cost can be reduced.

  Furthermore, the workpiece processing apparatus of the present invention comprises a moving means for moving the workpiece and the plasma generating nozzle relative to each other on a plane intersecting the plasma irradiation direction. A predetermined process is performed by irradiating the workpiece with plasma while moving.

  According to said structure, the workpiece | work processing apparatus which can perform plasma (plume) ignition reliably and rapidly is realizable.

  As described above, the plasma generating apparatus of the present invention is a plasma generating apparatus that can be used for workpiece processing, such as substrate modification, in which the plasma generating nozzle has a concentric inner conductor and outer conductor. A high-frequency pulse electric field is applied between them to generate a glow discharge to generate plasma, and a processing gas from a gas supply source is supplied between them, so that the nozzle at the tip is always used. In the plasma generator configured to radiate gas that has been converted into plasma under pressure to the workpiece, the inner conductor can be moved in and out in the axial direction, that is, in the plasma blowing direction, within the nozzle of the blowing port. Alternatively, the outer conductor is configured to be extendable and retracted, and at the time of plasma ignition, the tip surface of the inner conductor is moved backward relative to the tip surface of the outer conductor. An auxiliary means provided.

  Therefore, as the process gas flows, it passes from the vicinity of the tip of the inner conductor where the electric field is concentrated to the vicinity of the tip of the outer conductor, and thus changes from molecule to atom to plasma. It is easy to perform, and plasma (plume) ignition can be performed reliably and promptly.

  Furthermore, the work processing apparatus of the present invention, as described above, has moving means for moving the work and the plasma generating nozzle relative to each other on a plane intersecting the plasma irradiation direction. The workpiece is irradiated with plasma and subjected to a predetermined treatment while performing relative movement.

  Therefore, it is possible to realize a work processing apparatus capable of performing plasma (plume) ignition reliably and promptly.

[Embodiment 1]
FIG. 1 is a perspective view showing an overall configuration of a work processing apparatus S according to an embodiment of the present invention. The workpiece processing apparatus S includes a plasma generation unit PU (plasma generation apparatus) that generates plasma and irradiates the workpiece W, which is an object to be processed, with the plasma, and a predetermined route that passes the workpiece W through the plasma irradiation region. It is comprised from the conveyance means C which conveys. 2 is a perspective view of the plasma generation unit PU in which the line-of-sight direction is different from that in FIG. 1, and FIG. 3 is a partially transparent side view. 1 to 3, the XX direction is the front-rear direction, the Y-Y direction is the left-right direction, the ZZ direction is the up-down direction, the -X direction is the front direction, the + X direction is the rear direction,- Y will be described as a left direction, + Y direction as a right direction, -Z direction as a downward direction, and + Z direction as an upward direction.

  The plasma generation unit PU is a unit capable of generating plasma at normal temperature and pressure using microwaves. In general, the waveguide 10 propagates microwaves, and one end side of the waveguide 10 ( Microwave generator 20 arranged on the left side to generate microwaves of a predetermined wavelength, plasma generator 30 provided on waveguide 10, and arranged on the other end side (right side) of waveguide 10 to reflect microwaves The sliding short 40 to be performed, the circulator 50 for separating the reflected microwaves from the microwaves emitted to the waveguide 10 so as not to return to the microwave generator 20, and the dummy load 60 for absorbing the reflected microwaves separated by the circulator 50. In addition, a stub tuner 70 for matching impedance between the waveguide 10 and the plasma generation nozzle 31 is provided. The conveying means C includes a conveying roller 80 that is rotationally driven by a driving means (not shown). In the present embodiment, an example in which a flat workpiece W is conveyed by the conveying means C is shown.

  The waveguide 10 is made of a nonmagnetic metal such as aluminum, has a long tubular shape with a rectangular cross section, and propagates the microwave generated by the microwave generator 20 toward the plasma generator 30 in the longitudinal direction thereof. Is. The waveguide 10 is composed of a connected body in which a plurality of divided waveguide pieces are connected to each other by flange portions, and the first conductor on which the microwave generator 20 is mounted in order from one end side. The wave tube piece 11, the second waveguide piece 12 to which the stub tuner 70 is assembled, and the third waveguide piece 13 provided with the plasma generator 30 are connected. A circulator 50 is interposed between the first waveguide piece 11 and the second waveguide piece 12, and a sliding short 40 is connected to the other end side of the third waveguide piece 13.

  The first waveguide piece 11, the second waveguide piece 12, and the third waveguide piece 13 are each formed into a rectangular tube shape using an upper plate, a lower plate, and two side plates made of a metal flat plate. It is assembled and flange plates are attached to both ends thereof. In addition, you may make it use the rectangular waveguide piece formed by extrusion molding, the bending process of a plate-shaped member, etc., or a non-dividing type | mold waveguide irrespective of the assembly of such a flat plate. In addition, the waveguide is not limited to a rectangular cross section, and for example, a waveguide having an elliptical cross section can be used. Furthermore, not only a nonmagnetic metal but a waveguide can be comprised with the various members which have a waveguide effect | action.

  The microwave generator 20 includes, for example, an apparatus main body portion 21 including a microwave generation source such as a magnetron that generates a microwave of 2.45 GHz, and the microwave generated by the apparatus main body portion 21 inside the waveguide 10. And a microwave transmission antenna 22 that emits light to the outside. In the plasma generation unit PU according to the present embodiment, for example, a continuously variable microwave generator 20 that can output microwave energy of 1 W to 3 kW is preferably used.

  As shown in FIG. 3, the microwave generation device 20 has a configuration in which a microwave transmission antenna 22 protrudes from the device main body 21, and is fixed in a mode of being placed on the first waveguide piece 11. Has been. Specifically, the apparatus main body 21 is placed on the upper surface plate 11U of the first waveguide piece 11, and the microwave transmitting antenna 22 is inside the first waveguide piece 11 through the through hole 111 formed in the upper surface plate 11U. The waveguide space 110 is fixed so as to protrude. With this configuration, the microwave of 2.45 GHz, for example, emitted from the microwave transmission antenna 22 is directed from one end side (left side) to the other end side (right side) by the waveguide 10. Propagated.

The plasma generation unit 30 includes eight plasma generation nozzles 31 that are arranged in a row in the left-right direction on the lower surface plate 13B of the third waveguide piece 13 (the surface facing the workpiece to be processed). Configured. The width of the plasma generation unit 30, that is, the arrangement width in the left-right direction of the eight plasma generation nozzles 31 is a width that substantially matches the size t in the width direction orthogonal to the conveying direction of the flat workpiece W. Thereby, the plasma processing can be performed on the entire surface of the workpiece W (the surface facing the lower surface plate 13B) while the workpiece W is being conveyed by the conveying roller 80. The arrangement interval of the eight plasma generating nozzles 31 is preferably determined according to the wavelength lambda _G of the microwave propagating through the waveguide 10. For example, it is desirable to arrange the plasma generating nozzles 31 at a ½ pitch and a ¼ pitch of the wavelength λ _{G. When} a microwave of 2.45 GHz is used, since λ _G = 230 mm, 115 mm (λ _G / 2) The plasma generating nozzles 31 may be arranged at a pitch or 57.5 mm (λ _G / 4) pitch.

  4 is an enlarged side view showing two plasma generation nozzles 31 (one plasma generation nozzle 31 is drawn as an exploded view), and FIG. 5 is a cross-sectional view taken along line AA in FIG. A plasma generating nozzle 31 that is a plasma generating device includes a central conductor 32, a nozzle body 33, a nozzle holder 34, a seal member 35, a protective tube 36, and an electromagnetic solenoid 38.

  The central conductor 32 that is an inner conductor is made of a highly conductive metal such as copper, aluminum, or brass, and is made of a rod-shaped member having a diameter of about 1 to 5 mm. The upper end portion 321 side is the third waveguide piece 13. The lower end 322 is substantially flush with the lower end edge 331 of the nozzle body 33, while penetrating the lower surface plate 13B and projecting into the waveguide space 130 by a predetermined length (this projecting portion is referred to as a receiving antenna unit 320). As shown in FIG. Microwave energy (microwave power) is applied to the central conductor 32 when the receiving antenna unit 320 receives the microwave propagating through the waveguide 10. The central conductor 32 is held by a seal member 35 at a substantially intermediate portion in the length direction.

  The nozzle body 33 which is an outer conductor is a cylindrical body made of a highly conductive metal and having a cylindrical space 332 in which the central conductor 32 is accommodated. Similarly, the nozzle holder 34 as an outer conductor is also made of a highly conductive metal, and has a relatively large-diameter lower holding space 341 that holds the nozzle body 33 and a relatively small-diameter upper part that holds the seal member 35. A cylindrical body having a holding space 342. On the other hand, the seal member 35 is made of a heat-resistant resin material such as Teflon (registered trademark) or an insulating member such as ceramic, and has a holding hole 351 for holding the central conductor 32 fixedly on its central axis. It consists of a body

  The nozzle body 33 is provided in an annularly projecting manner from the upper side, an upper body part 33U fitted in the lower holding space 341 of the nozzle holder 34, an annular recess 33S for holding a gas seal ring 37 described later. A flange portion 33F and a lower body portion 33B protruding from the nozzle holder 34 are provided. In addition, a communication hole 333 for supplying a predetermined processing gas to the cylindrical space 332 is formed in the upper body portion 33U.

  The nozzle body 33 and the nozzle holder 34 function as the outer conductor disposed around the center conductor 32, and the center conductor 32 has a predetermined annular space H (insulation interval) secured around it. In this state, it is inserted through the central axis of the cylindrical space 332. The nozzle body 33 has a nozzle holder such that the outer peripheral portion of the upper body portion 33U is in contact with the inner peripheral wall of the lower holding space 341 of the nozzle holder 34 and the upper end surface of the flange portion 33F is in contact with the lower end edge 343 of the nozzle holder 34. 34 is fitted. The nozzle body 33 is preferably attached to the nozzle holder 34 with a detachable fixing structure using, for example, a plunger or a set screw.

  The nozzle holder 34 includes an upper body portion 34U (corresponding approximately to the position of the upper holding space 342) and a lower surface plate 13B that are closely fitted in a through hole 131 formed in the lower surface plate 13B of the third waveguide piece 13. And a lower body portion 34B (substantially corresponding to the position of the lower holding space 341). A gas supply hole 344 for supplying a processing gas to the annular space H is formed in the outer periphery of the lower body portion 34B. Although not shown, a pipe joint or the like for connecting a terminal portion of a gas supply pipe for supplying a predetermined processing gas is attached to the gas supply hole 344. The gas supply hole 344 and the communication hole 333 of the nozzle body 33 are set so that they are in communication with each other when the nozzle body 33 is fitted into the nozzle holder 34 at a fixed position. A gas seal ring 37 is interposed between the nozzle body 33 and the nozzle holder 34 in order to suppress gas leakage from the abutting portion between the gas supply hole 344 and the communication hole 333.

  A plurality of the gas supply holes 344 and the communication holes 333 may be perforated at equal intervals in the circumferential direction, and are not perforated in the radial direction toward the center. The gas may be perforated in the tangential direction of the outer peripheral surface of the cylindrical space 332 so as to swirl the gas. Further, the gas supply hole 344 and the communication hole 333 are not perpendicular to the central conductor 32, and may be formed obliquely from the upper end 321 side to the lower end 322 side in order to improve the flow of the processing gas. Good.

  The seal member 35 has a lower end edge 352 in contact with an upper end edge 334 of the nozzle body 33 and an upper end edge 353 in contact with an upper end locking portion 345 of the nozzle holder 34 in the upper holding space 342 of the nozzle holder 34. Is retained. That is, the upper holding space 342 is assembled so that the seal member 35 supporting the central conductor 32 is fitted and the lower end edge 352 of the nozzle body 33 is pressed by the upper end edge 334. is there.

  The protective tube 36, which is a nozzle for the outlet, is made of a transparent quartz glass pipe or the like having a predetermined length, and has an outer diameter that is substantially equal to the inner diameter of the cylindrical space 332 of the nozzle body 33. The protective tube 36 has a function of preventing abnormal discharge (arcing) at the lower end edge 331 of the nozzle body 33 and radiating a plume P to be described later normally. The cylindrical space 332 is inserted so as to protrude from the edge 331. Note that the entire protective tube 36 may be accommodated in the cylindrical space 332 so that the tip end thereof coincides with the lower end edge 331 or enters the inner side of the lower end edge 331.

  As a result of the plasma generation nozzle 31 being configured as described above, the nozzle body 33, the nozzle holder 34, and the third waveguide piece 13 (waveguide 10) are in a conductive state (the same potential), Since the central conductor 32 is supported by the insulating seal member 35, it is electrically insulated from these members. Therefore, as shown in FIG. 6, when the microwave is received by the receiving antenna unit 320 of the central conductor 32 and the microwave power is supplied to the central conductor 32 in a state where the waveguide 10 is at the ground potential. An electric field concentration portion is formed in the vicinity of the lower end portion 322 and the lower end edge 331 of the nozzle body 33.

  In this state, when an oxygen-based processing gas such as oxygen gas or air is supplied from the gas supply hole 344 to the annular space H, the processing gas is excited by the microwave power and the lower end of the central conductor 32 is excited. Plasma (ionized gas) is generated near the portion 322. Although this plasma has an electron temperature of tens of thousands of degrees, the gas temperature is a reactive plasma that is close to the outside temperature (a plasma in which the electron temperature indicated by electrons is extremely high compared to the gas temperature indicated by neutral molecules). It is a plasma generated under normal pressure.

  The processing gas thus converted into plasma is radiated from the lower edge 331 of the nozzle body 33 as a plume P by the gas flow provided from the gas supply hole 344. This plume P contains radicals. For example, when an oxygen-based gas is used as the processing gas, oxygen radicals are generated, and the plume P having an organic substance decomposition / removal action, a resist removal action, and the like can be obtained. In the plasma generation unit PU according to the present embodiment, since a plurality of plasma generation nozzles 31 are arranged, it is possible to generate a line-shaped plume P extending in the left-right direction.

  Incidentally, when an inert gas such as argon gas or nitrogen gas is used as the processing gas, the surface cleaning and surface modification of various substrates can be performed. Further, if a compound gas containing fluorine is used, the substrate surface can be modified to a water-repellent surface, and using a compound gas containing a hydrophilic group can modify the substrate surface to a hydrophilic surface. Furthermore, if a compound gas containing a metal element is used, a metal thin film layer can be formed on the substrate.

  In the plasma generating nozzle 31 configured as described above, it should be noted that in the present embodiment, the lower end portion 322 of the central conductor 32 serving as the inner conductor is connected to the lower end edge 331 of the nozzle body 33 as described above. Although arranged vertically so as to be substantially flush with each other, its length can be slightly expanded and contracted, and the length of the electromagnetic solenoid 37, which is an ignition assisting means, during ignition and during steady lighting. Is adjustable.

  Specifically, the lower end portion 322 of the central conductor 32 includes an outer cylindrical portion 3221 and an inner cylindrical portion 3222 that are retractable and retractable. The outer cylinder portion 3221 is integrated with an upper end portion 321 serving as the receiving antenna portion 320, and a guide hole 3221a is formed in the axial direction from the lower end side. Correspondingly, the inner cylindrical portion 3222 is actually formed opposite to the lower end edge 331 of the nozzle body 33 and formed with a lower diameter portion 3222a that forms an electric field concentration portion, and a smaller diameter than the lower end portion 3222a, It is configured to include an upper end portion 3222b that fits into the guide hole 3221a and is slidable in the axial direction.

  The upper end (base end) side of the lower end portion 3222a is connected to an electrically insulating and nonmagnetic connecting member 39. In the lower body portion 33B of the nozzle body 33, the connecting member 39 communicates the inner peripheral side and the outer peripheral side, and loosely inserts a long hole 33H formed extending in the direction of the axis (plasma blowing). On the side, it is connected to an operating piece (actuator) 381 of the electromagnetic solenoid 38 attached to the outer peripheral surface of the lower body portion 33B.

  As will be described later, the operating piece 381 of the electromagnetic solenoid 38 is extended during plasma ignition, whereby the front end surface 3222c of the lower end portion 3222a of the inner cylinder portion 3222 is retracted from the lower end edge 331 of the nozzle body 33, At the time of steady lighting, it is degenerated, and as a result, the front end surface 3222c of the lower end portion 3222a of the inner cylinder portion 3222 protrudes from the lower end edge 331 of the nozzle body 33. In FIG. 5, for the sake of easy understanding, the protection tube 36 is omitted, and the inner cylindrical portion 3222 is projected, that is, a state in steady lighting is shown.

  This is based on the experiment results of the present inventors. First, at the time of steady lighting, the lower end portion 3222a of the central conductor 32 serving as the end of the coaxial transmission line is protruded from the lower end edge 331 of the nozzle main body 33, thereby An electric field is formed between the lower end edge 331 of 33 and an inner side portion having an impedance smaller than that of the tip end portion of the lower end portion 3222a, which is excellent in stability and has a microwave power when continuously lit. This is because the size can be reduced, power consumption can be suppressed, and the lifetime of the microwave generator 20 can be extended. However, when doing so, the ignitability deteriorates. For this reason, at the time of plasma ignition, the lower end portion 3222a of the central conductor 32 is retracted from the lower end edge 331 of the nozzle body 33, so that the processing gas flows and the central conductor 32 in which an electric field concentrates. Since it passes from the vicinity of the lower end portion 3222a of the nozzle to the vicinity of the lower end edge 331 of the nozzle body 33, it is easy to change from molecule to atom to plasma, and plasma (plume) ignition can be performed reliably and promptly. It is.

  FIG. 11 and Table 1 show the experimental results of the inventors. FIG. 11 is a graph showing changes in the loss of the plasma generating nozzle 31 when the length of the anode, that is, the central conductor 32 during steady lighting is changed. The outer diameter of the lower end portion 3222a of the central conductor 32 is 1.6 mm, the inner diameter of the cylindrical space 332 of the nozzle body 33 is 6 mm, and the protective tube 36 is removed. Reference symbol α1 is when the flow rate of the processing gas is 1 l / min, and reference symbol α1 is when the flow rate of the processing gas is 3 l / min. The microwave power supplied from the microwave generator 20 is 500 W, and the cathode length, that is, the height of the cylindrical space 332 is 40 mm.

  As is apparent from FIG. 11, when the flow rate is small (α1), if the anode length is equal to or longer than the cathode length, the loss is small, that is, the efficiency with which a given microwave is used for plasma generation is low. When the flow rate is high and the flow rate is large (α2), the efficiency is highest when the length of the anode is 2 mm longer than the length of the cathode. The same tendency appears even when the flow rate of the processing gas is further increased. Therefore, in the present embodiment, the lower end portion 3222a of the central conductor 32 is projected by 2 mm from the lower end edge 331 of the nozzle body 33 during steady lighting.

  On the other hand, as can be seen from Table 1, it is understood that, during plasma ignition, the lower the end 3222a of the central conductor 32 is, the easier it is to ignite as the lower end 331 of the nozzle body 33 is retracted. However, when the bottom end 3222a of the central conductor 32 is retracted by 2 mm from the lower end edge 331 of the nozzle body 33, the length facing the cathode is short, so that it is left for a long time. Thus, the central conductor 32 may be burned out. Therefore, if it takes time to adjust the stub tuner 70 and the sliding short 40, which will be described later, the center conductor 32 may be burned as described above. Therefore, in the present embodiment, the lower end portion of the center conductor 32 during plasma ignition. Assume that 3222a is retracted 1 mm from the lower end edge 331 of the nozzle body 33.

  The sliding short 40 is provided for optimizing the coupling state between the central conductor 32 provided in each plasma generation nozzle 31 and the microwave propagated inside the waveguide 10. The third wave guide piece 13 is connected to the right end of the third waveguide piece 13 so that the standing wave pattern can be adjusted by changing the microwave reflection position. Therefore, when a standing wave is not used, a dummy load having a radio wave absorption function is attached instead of the sliding short 40.

  FIG. 7 is a perspective view showing the internal structure of the sliding short 40. As shown in FIG. 7, the sliding short 40 includes a housing structure having a rectangular cross section similar to that of the waveguide 10, and a housing portion 41 having a hollow space 410 made of the same material as the waveguide 10. A cylindrical reflecting block 42 housed in the hollow space 410, a rectangular block 43 that is integrally attached to the base end of the reflecting block 42 and slides in the left-right direction in the hollow space 410, and A moving mechanism 44 assembled to the rectangular block 43 and an adjusting knob 46 directly connected to the reflecting block 42 via a shaft 45 are provided.

  The reflection block 42 is a cylindrical body that extends in the left-right direction so that a tip surface 421 serving as a microwave reflection surface faces the waveguide space 130 of the third waveguide piece 13. The reflection block 42 may have a prismatic shape similar to that of the rectangular block 43. The moving mechanism 44 is a mechanism for propelling or retreating the rectangular block 43 and the reflecting block 42 integrated with the rectangular block 43 in the left-right direction by rotating the adjusting knob 46. 42 is movable in the left-right direction while being guided by the rectangular block 43 in the hollow space 410. The standing wave pattern is optimized by adjusting the position of the tip surface 421 by the movement of the reflection block 42. It is desirable to automate the rotation operation of the adjusting knob 46 using a stepping motor or the like.

  The circulator 50 is composed of, for example, a waveguide-type three-port circulator with a built-in ferrite column. Of the microwaves once propagated toward the plasma generator 30, the plasma generator 30 returns without being consumed. The incoming reflected microwave is directed to the dummy load 60 without returning to the microwave generator 20. By arranging such a circulator 50, the microwave generator 20 is prevented from being overheated by the reflected microwave.

  FIG. 8 is a top view of the plasma generation unit PU for explaining the operation of the circulator 50. As shown, the first port 51 of the circulator 50 has a first waveguide piece 11, the second port 52 has a second waveguide piece 52, and the third port 53 has a dummy load 60. It is connected. Then, the microwave generated from the microwave transmission antenna 22 of the microwave generator 20 travels from the first port 51 to the second waveguide piece 12 via the second port 52 as indicated by an arrow a. On the other hand, the reflected microwave incident from the second waveguide piece 12 side is deflected from the second port 52 toward the third port and incident on the dummy load 60 as indicated by an arrow b.

  The dummy load 60 is a water-cooled (or air-cooled) radio wave absorber that absorbs the reflected microwave and converts it into heat. The dummy load 60 is provided with a cooling water circulation port 61 for circulating cooling water therein so that heat generated by heat conversion of the reflected microwaves is exchanged with the cooling water. It has become.

  The stub tuner 70 is for impedance matching between the waveguide 10 and the plasma generation nozzle 31, and has three stub tuners arranged in series on the upper surface plate 12 U of the second waveguide piece 12 at a predetermined interval. Units 70A to 70C are provided. FIG. 9 is a perspective side view showing an installation state of the stub tuner 70. As shown in the figure, the three stub tuner units 70 </ b> A to 70 </ b> C have the same structure, a stub 71 protruding into the waveguide space 120 of the second waveguide piece 12, and an operation rod 72 directly connected to the stub 71. And a moving mechanism 73 for moving the stub 71 up and down in the vertical direction, and an outer jacket 74 for holding these mechanisms.

  In the stub 71 provided in each of the stub tuner units 70 </ b> A to 70 </ b> C, the protruding length into the waveguide space 120 can be adjusted independently by each operation rod 72. The protruding lengths of the stubs 71 are determined by searching for a point where the power consumption by the central conductor 32 is maximized (a point where the reflected microwave is minimized) while monitoring the microwave power. Such impedance matching is executed in conjunction with the sliding short 40 as necessary. The operation of the stub tuner 70 is preferably automated using a stepping motor or the like.

  The conveyance means C includes a plurality of conveyance rollers 80 arranged along a predetermined conveyance path, and the conveyance roller 80 is driven by a driving means (not shown), so that the workpiece W to be processed is generated by the plasma generation. It is conveyed via the section 30. Here, examples of the workpiece W to be processed include a flat substrate such as a plasma display panel and a semiconductor substrate, a circuit substrate on which electronic components are mounted, and the like. Also, parts or assembled parts that are not flat-shaped can be processed, and in this case, a belt conveyor or the like may be employed instead of the conveying roller. Next, an electrical configuration of the work processing apparatus S according to the present embodiment will be described. FIG. 10 is a block diagram showing a control system of the work processing apparatus S. This control system includes a CPU (central processing unit) 901 and an overall control unit 90 including its peripheral circuits, a microwave output control unit 91 including an output interface and a drive circuit, a gas flow rate control unit 92, and conveyance control. Unit 93 and solenoid drive control unit 98, a display means, an operation panel, and the like, and an operation unit 95 for giving a predetermined operation signal to the overall control unit 90, an input interface, an analog / digital converter, and the like. The sensor input units 96 and 97, the sensors 961 and 971, the drive motor 931, and the flow rate control valve 923 are configured.

  The microwave output control unit 91 performs ON / OFF control and output intensity control of the microwave output from the microwave generator 20. The microwave output controller 91 generates the 2.45 GHz pulse signal and The operation control of the microwave generation by the apparatus main body 21 is performed.

  The gas flow rate control unit 92 controls the flow rate of the processing gas supplied to each plasma generation nozzle 31 of the plasma generation unit 30. Specifically, the opening degree of the flow rate control valve 923 provided in the gas supply pipe 922 connecting the processing gas supply source 921 such as a gas cylinder and each plasma generating nozzle 31 is adjusted.

  The conveyance control unit 93 controls the operation of the drive motor 931 that rotationally drives the conveyance roller 80, and controls the start / stop of conveyance of the workpiece W, the conveyance speed, and the like.

  The overall control unit 90 is responsible for overall operation control of the work processing apparatus S. The measurement result of the flow rate sensor 961 input from the sensor input unit 96 according to the operation signal given from the operation unit 95, the sensor The measurement result of the conveyance speed of the workpiece W by the speed sensor 971 input from the input unit 97 is monitored, and the microwave output control unit 91, the gas flow rate control unit 92, the conveyance control unit 93, and the solenoid drive control unit 98 are Operation control is performed based on a predetermined sequence.

  Specifically, the CPU 901 starts the conveyance of the workpiece W based on a control program stored in advance in the memory 902, guides the workpiece W to the plasma generation unit 30, and generates a processing gas having a predetermined flow rate for each plasma. Plasma (plume P) is generated by supplying microwave power while being supplied to the nozzle 31, and the plume P is radiated on the surface of the workpiece W while it is being conveyed. Thereby, a plurality of works W are processed continuously.

  At this time, the CPU 901 monitors the measurement result of the flow rate sensor 961 provided for each of the plurality of plasma generation nozzles 31 and is measured and stored in advance by the manufacturer in the memory 903 which is a storage unit. Based on the control program stored in the memory 902, the flow rate control valve 923 is opened so as to read the plasma output characteristics such as the plume size and shape corresponding to the flow rate and the plasma temperature. Adjust each degree. For example, the flow rate is increased when the plume P is increased, and the flow rate is decreased when the plasma temperature is increased. Further, when the height is different due to electronic parts being mounted on the workpiece W, the height of the plume P from each plasma generating nozzle 31 can be changed.

  The CPU 901 drives and controls the electromagnetic solenoid 38 of each plasma generating nozzle 31 via the solenoid drive control unit 98, and the lower end portion 3222 a of the central conductor 32 is moved from the lower end edge 331 of the nozzle body 33 during plasma ignition. Further, when the ignition is performed, the operation of causing the plasma generating nozzles 31 to project by 2 mm is sequentially performed on each plasma generating nozzle 31 from, for example, the side far from the microwave generator 20 (sliding short 40).

  According to the workpiece processing apparatus S described above, the workpiece W is transported by the workpiece transport means C, and the plasmaized gas from the plasma generating nozzles 31 arranged and attached to the waveguide 10 is supplied to the workpiece W. Since it can radiate | emit with respect to a workpiece | work, a plasma processing can be continuously performed with respect to several to-be-processed workpiece | work, and a plasma processing can be efficiently performed also about the workpiece | work of a large area. Therefore, it is possible to provide the work processing apparatus S or the plasma generation apparatus PU that is superior in plasma processing workability to various types of workpieces as compared with batch processing type work processing apparatuses. Moreover, since plasma can be generated at an external temperature and pressure, a vacuum chamber or the like is not required, and the equipment configuration can be simplified.

  Further, the microwave generated from the microwave generator 20 is received by the central conductor 32 provided in each plasma generation nozzle 31, and the gas generated from each plasma generation nozzle 31 based on the energy of the microwave is converted into plasma. Therefore, the transmission system of the energy held by the microwave to each plasma generating nozzle 31 can be simplified. Therefore, simplification of the device configuration, cost reduction, and the like can be achieved.

  Further, since the plasma generation unit 30 in which the plurality of plasma generation nozzles 31 are arranged in a line has a width that substantially matches the size t in the width direction orthogonal to the conveyance direction of the flat workpiece W, By simply passing the workpiece W through the plasma generating unit 30 only once by the conveying means C, the processing of the entire surface can be completed, and the plasma processing efficiency for the plate-shaped workpiece can be remarkably improved. In addition, plasmaized gas can be radiated to the workpiece W being conveyed at the same timing, and uniform surface treatment or the like can be performed.

  Furthermore, the lower end portion 322 of the central conductor 32 is composed of an extendable outer cylindrical portion 3221 and an inner cylindrical portion 3222 with respect to the plurality of plasma generating nozzles 31, and plasma is generated by an electromagnetic solenoid 38 which is a lighting auxiliary means. At the time of ignition, the front end surface 3222c of the lower end portion 3222a of the inner cylinder portion 3222 is retracted by 1 mm from the lower end edge 331 of the nozzle body 33, and when ignited, it is projected by 2 mm. Sometimes the plasma (plume P) can be turned on reliably and promptly, which is particularly suitable when a large number of plasma generating nozzles 31 are provided, and the size of the plasma (plume P) during steady lighting. Even without changing, power consumption can be reduced.

  The retreat of the center conductor 32 at the time of plasma ignition as described above and the protrusion of the center conductor 32 at the time of steady lighting are not necessarily used together. For example, the tip of the lower end portion 3222a of the center conductor 32 is used. The position where the surface 3222c and the lower end edge 331 of the nozzle main body 33 are aligned may be used as a reference position, and the central conductor 32 may be configured to retract only during plasma ignition, or may be configured to protrude only during steady lighting. . However, by using both methods in combination, the positional relationship between the front end surface 322b of the central conductor 32 and the lower end edge 331 of the nozzle body 33 during plasma lighting and steady lighting is always maintained optimally, and ignition as described above is performed. It is possible to achieve both the effects of improving the performance and reducing the power consumption.

  In addition, when commercial alternating current is used as a power source for the microwave generator 20 and the internal power source of the magnetron rectifies the entire wave and turns on the plasma (plume P) by alternating current, for example, it blinks at 120 Hz at a power frequency of 60 Hz. Will be done. Such re-lighting during continuous lighting is not steady lighting in the present invention, but steady lighting. At the time of lighting targeted by the present invention, the supply of processing gas is started, This is when power begins to be supplied.

  In addition, by changing the length of the central conductor 32 in this manner, the ignition performance is improved, so that the microwave power is not significantly adjusted before and after the plasma ignition, and the stub tuner 70 and the sliding short 40 are adjusted. Can also be reduced.

[Embodiment 2]
FIG. 12 is a longitudinal sectional view showing the structure of a plasma generating nozzle 31a according to another embodiment of the present invention. The plasma generation nozzle 31a is similar to the plasma generation nozzle 31 shown in FIG. 5 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in this plasma generating nozzle 31a, the central conductor 32a, which is an inner conductor, is formed in an integral rod shape from the upper end 321 to the lower end 322, whereas the nozzle body, which is an outer conductor, is formed. The lower body 33Ba, which is the tip of 33a, is composed of an outer cylinder 33Ba1 and an inner cylinder 33Ba2 that can be retracted and retracted in a retractable manner, and the electromagnetic solenoid 38 drives the inner cylinder 33Ba2 to extend and contract. It is.

  The inner cylindrical portion 33Ba2 includes a cylindrical portion 33Ba21 that forms the cylindrical space 332, a folded portion 33Ba22 that extends in a bowl shape from the tip (lower end) side, and a tubular portion in which the free end side of the folded portion 33Ba22 is further folded. 33Ba23, and the cylindrical portions 33Ba21 and 33Ba2 sandwich the tip (lower end) of the outer cylindrical portion 33Ba1 and are slidably displaceable. The electromagnetic solenoid 38 is attached to the outer cylinder portion 33Ba1 at a position that does not hinder the sliding displacement of the inner cylinder portion 33Ba2, and the operating piece 381 is connected to the cylinder portion 33Ba23 of the inner cylinder portion 33Ba2 via a connecting member 39. Has been.

  The operating piece 381 of the electromagnetic solenoid 38 is degenerated at the time of plasma ignition, whereby the front end surface 322b of the lower end portion 322a of the central conductor 32a is retracted from the lower end edge 331 of the inner cylinder portion 33Ba2 and is steadily lit. It is sometimes extended so that the front end surface 322b of the lower end portion 322a protrudes from the lower end edge 331 of the inner cylinder portion 33Ba2. In FIG. 12, the state at the time of the plasma ignition which cylinder part 33Ba2 protruded is shown.

  Also with this configuration, the plasma (plume P) can be turned on reliably and promptly at the time of plasma ignition, and the power consumption can be maintained even when the size of the plasma (plume P) does not change during steady lighting. Can be reduced. Further, according to the above configuration, although the movable portion is somewhat larger, the outer diameter of the inner conductor and the inner diameter of the outer conductor, that is, the impedance change is small, and at the time of plasma ignition, the lower end portion 322a of the central conductor 32a. The front end surface 322b is retracted from the lower end edge 331 of the inner cylinder portion 33Ba2, and the front end surface 322b of the lower end portion 322a is protruded from the lower end edge 331 of the inner cylinder portion 33Ba2 during steady lighting.

[Embodiment 3]
FIG. 13 is a longitudinal sectional view showing the structure of a plasma generating nozzle 31b according to still another embodiment of the present invention. The plasma generation nozzle 31b is similar to the plasma generation nozzles 31 and 31a described above, and corresponding portions are denoted by the same reference numerals, and description thereof is omitted. It should be noted that in this plasma generation nozzle 31b, the central conductor 32a, which is an inner conductor, is formed in an integrated rod shape from the upper end 321 to the lower end 322, as in the plasma generation nozzle 31a described above, The nozzle body 33, which is a conductor, is configured in the same manner as the plasma generating nozzle 31 described above, whereas in the nozzle holder 34b, which is another outer conductor, in the upper holding space 342b of the upper body 34Ub. The seal member 35 to which the central conductor 32 a is attached is slidable up and down and is driven and displaced by the electromagnetic solenoid 38.

  Specifically, the upper holding space 342b has a slightly larger diameter than the upper holding space 342, and is formed vertically longer by the amount of displacement of the central conductor 32a and the seal member 35. 348 and 349 abut against the lower end edge 352 and the upper end edge 353 of the seal member 35 that are displaced up and down to prevent the seal member 35 from falling off the upper holding space 342b. A connecting member 39 connected to an operating piece 381 of the electromagnetic solenoid 38 attached to the outer peripheral surface of the upper body 34Ub loosely inserts a long hole 34H formed in the upper body 34Ub, and the seal member By being connected to 35, the seal member 35 to which the central conductor 32a is attached as described above is driven and displaced up and down.

  The operation of the electromagnetic solenoid 38 is the same as that in the case of FIG. 5 described above, and the operating piece 381 is extended at the time of plasma ignition, whereby the front end surface 322b of the lower end 322 of the central conductor 32a is Retreating from the lower end edge 331 and degenerating at the time of steady ignition, the leading end surface 322b of the lower end portion 322 of the central conductor 32a protrudes from the lower end edge 331 of the nozzle body 33. FIG. 13 shows a state at the time of ignition.

  In order to make the seal member 35 and the central conductor 32a replaceable, for example, a hole for loose insertion of the central conductor 32a is formed at the center of the upper locking portion 34 and can be screwed to the upper trunk portion 34Ub. What is necessary is just to devise suitably, such as forming in a cap type. Alternatively, when it is possible to prevent the connecting member 39 from coming off, it may be omitted.

  With this configuration, the upper end portion 321 on the waveguide 10 side with respect to the seal member 35 of the central conductor 32a serving as the receiving antenna unit 320 protrudes from the waveguide space 130 during ignition and during steady lighting. It will retreat. Accordingly, the reception microwave energy of the reception antenna unit 320 is increased at the time of ignition, and the ignition can be facilitated. In particular, when the plasma generating nozzles 31 arranged in the waveguide 10 are sequentially turned on, when the light is turned on, the receiving antenna unit 320 becomes higher than the other nozzles, and it becomes easier to receive microwaves. When it is lit, it becomes low so that it does not interfere with microwave reception at the receiving antenna section of the other nozzles. In this way, the microwave generator 20 having the minimum necessary power can be used.

The work processing apparatus S according to the embodiment of the present invention has been described above, but the present invention is not limited to this, and for example, the following embodiment can be taken.
(1) In the above embodiment, an example in which a plurality of plasma generating nozzles 31 are arranged in a line is shown. However, the nozzle arrangement may be appropriately determined according to the shape of the workpiece W, the power of microwave power, and the like. The plurality of rows of plasma generating nozzles 31 may be arranged in a matrix or in a staggered arrangement in the conveyance direction of the workpiece W.
(2) In the above-described embodiment, the transport unit C that transports the workpiece W is used as the moving unit. As the transport unit C, a mode in which the workpiece W is mounted on the upper surface of the transport roller 80 and transported is exemplified. In addition to this, for example, a form in which the work W is nipped between the upper and lower transport rollers and transported, a form in which the work is stored in a predetermined basket or the like without using the transport roller, and the basket or the like is transported by a line conveyor or the like, or a robot hand For example, the workpiece W may be gripped and conveyed to the plasma generation unit 30 by using a method such as that described above. Alternatively, the moving means may be configured to move the plasma generating nozzle 31 side. That is, the workpiece W and the plasma generation nozzle 31 may be relatively moved on a plane (X, Y plane) intersecting with the plasma irradiation direction (Z direction).
(3) In the above embodiment, a magnetron that generates a microwave of 2.45 GHz is illustrated as a microwave generation source. However, various high-frequency power sources other than the magnetron can be used, and a microwave having a wavelength different from 2.45 GHz. A wave may be used.
(4) In order to measure the microwave power in the waveguide 10, it is desirable to install a power meter at an appropriate position of the waveguide 10. For example, in order to know the ratio of the reflected microwave power to the microwave power emitted from the microwave transmission antenna 22 of the microwave generator 20, a power meter is provided between the circulator 50 and the second waveguide piece 12. Can be interposed.

  A workpiece processing apparatus and a plasma generation apparatus according to the present invention include an etching processing apparatus and a film forming apparatus for a semiconductor substrate such as a semiconductor wafer, a glass substrate such as a plasma display panel and a cleaning processing apparatus for a printed board, and a sterilization process for medical equipment The present invention can be suitably applied to an apparatus, a protein decomposition apparatus, and the like.

It is a perspective view which shows the whole structure of the workpiece processing apparatus which concerns on this invention. FIG. 2 is a perspective view of a plasma generation unit with a different line-of-sight direction from FIG. 1. It is a partial see-through | perspective side view of a workpiece | work processing apparatus. It is a side view which expands and shows two plasma generation nozzles (one plasma generation nozzle is drawn as an exploded view). It is the sectional view on the AA line side of FIG. It is a see-through | perspective side view for demonstrating the generation state of the plasma in a plasma generation nozzle. It is a see-through | perspective perspective view which shows the internal structure of a sliding short. It is a top view of the plasma generation unit for demonstrating the effect | action of a circulator. It is a see-through | perspective side view which shows the installation condition of a stub tuner. It is a block diagram which shows the control system of a workpiece processing apparatus. It is a graph which shows the change of the loss of the plasma generation nozzle at the time of changing the length of the anode at the time of steady lighting which shows the experimental result of this inventor. It is a longitudinal cross-sectional view which shows the structure of the plasma generation nozzle which concerns on other embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of the plasma generation nozzle which concerns on other form of implementation of this invention.

Explanation of symbols

10 Waveguide 20 Microwave generator (microwave generator)
30 Plasma generators 31, 31a, 31b Plasma generating nozzles 32, 32a Central conductor (internal conductor)
320 receiving antenna part 321 upper end part 322 lower end part 3221 outer cylinder part 3222 inner cylinder part 33, 33a nozzle body (external conductor)
33Ba Lower body part 33Ba1 Outer cylinder part 33Ba2 Inner cylinder part 34, 34b Nozzle holder 342, 342b Upper holding space 344 Gas supply hole (gas supply part)
34 Ub Upper body part 36 Protective tube 38 Electromagnetic solenoid 39 Connecting member 40 Sliding short 50 Circulator 60 Dummy load 70 Stub tuner 80 Conveying roller 90 Overall controller 901 CPU
902, 903 Memory 91 Microwave output control unit 92 Gas flow rate control unit 921 Processing gas supply source 922 Gas supply pipe 923 Flow rate control valve 93 Transport control unit 931 Drive motor 95 Operation units 96, 97 Sensor input unit 98 Solenoid drive control unit S Work processing equipment PU Plasma generation unit (plasma generator)
C Conveying means W Workpiece

Claims (7)

Using a plasma generating nozzle with concentric inner and outer conductors and applying a high-frequency pulsed electric field between the two conductors, a glow discharge is generated near the tip of both conductors to generate plasma. In the plasma generator that radiates the gas to be processed into a workpiece under normal pressure from the nozzle of the outlet by supplying a processing gas from a gas supply source between them,
A plasma generating apparatus comprising ignition auxiliary means for retreating the front end surface of the inner conductor relative to the front end surface of the outer conductor, during plasma ignition.   2. The plasma generating apparatus according to claim 1, wherein the ignition assisting means causes the tip surface of the inner conductor to protrude relative to the tip surface of the outer conductor when the plasma is steadily lit.   The inner conductor includes a collapsible outer cylinder part and an inner cylinder part that are freely retractable and retractable, and the ignition auxiliary means is an electromagnetic solenoid in which an operating piece is connected to a proximal end side of the inner cylinder part. The plasma generator according to claim 1 or 2, wherein the plasma generator is formed.   The front end portion of the outer conductor is separately formed into an outer cylinder portion and a retractable inner cylinder portion that can be retracted and retracted within the outer cylinder portion. 3. The plasma generator according to claim 1, comprising an electromagnetic solenoid coupled to the inner cylinder portion. The microwave from the microwave generation means is propagated by the waveguide and received by the inner conductor of the plasma generation nozzle protruding into the waveguide space,
The inner conductor is held between the outer conductor by an electrically insulating seal member, and the seal member is slidable in the cylindrical axial direction with the inner peripheral surface of the cylindrical outer conductor. The plasma generating apparatus according to claim 1, wherein the ignition assisting unit includes an electromagnetic solenoid having an operating piece coupled to the seal member.   6. The microwave from the microwave generation means is propagated by a waveguide, and a plurality of the plasma generation nozzles are arranged and attached in the waveguide of the plasma generation unit. 2. The plasma generator according to claim 1.   The plasma generating apparatus according to any one of claims 1 to 6, further comprising a moving unit that relatively moves the workpiece and the plasma generating nozzle on a surface intersecting with the plasma irradiation direction. A workpiece processing apparatus for performing predetermined processing by irradiating the workpiece with plasma while performing smooth movement.

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