JP2008077925A - Plasma generating device and work processor using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out plasma irradiation uniformly among respective nozzles when coping with processing or the like of a plurality of workpieces to be processed and the workpiece to be processed of a large area by installing the plurality of plasma generating nozzles at a waveguide tube in a plasma generating device used for processing or the like of the workpiece such as reforming of a substrate. <P>SOLUTION: A terminal end member 40 is installed at the terminal end of the waveguide tube 10 in which the plurality of the plasma generating nozzles 31 are arranged and the terminal end member 40 are commonly used for both a dummy load 41 to absorb microwaves and a reflecting member 42 to reflect them. Accordingly, first, a useless waste of the microwaves can be suppressed by the reflecting member 42, and next, by excessive reflection (over-returning) of the microwaves by the reflecting member 42, microwave energies received by the respective plasma generating nozzles 31 can be suppressed from becoming unbalanced. Thus, while increasing utilization efficiency of the microwaves, the plasma irradiation can be carried out uniformly from the respective plasma generating nozzles 31. <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.

The applicant of the present invention previously attached a plurality of such plasma generation nozzles to the waveguide in Patent Document 2, and propagates microwaves from the microwave generation means to each plasma generation nozzle via the waveguide. Therefore, we proposed a workpiece processing device that can process large-scale workpieces and multiple workpieces at once.
JP 2003-197397 A Japanese Patent Application No. 2006-45098

  The above-described prior art is an excellent workpiece processing apparatus that can surely process a large-scale workpiece or a plurality of workpieces collectively by performing plasma irradiation simultaneously from a plurality of plasma generating nozzles. However, at the rear end of the waveguide, called a sliding short, the standing wave pattern is adjusted by moving the reflection block that totally reflects the microwave back and forth in the axial direction of the waveguide, making the microwave efficient. A mechanism that can be used automatically is provided. Therefore, although the microwave can be efficiently used by the total reflection, there is a problem that the microwave energy received by each plasma generation nozzle becomes unbalanced due to the excessive reflection (return) of the microwave. In particular, the energy of the plasma generating nozzle at the rearmost end becomes high, and the microwave energy that can be received is greatly different from the previous or second previous plasma generating nozzle.

  On the other hand, if a dummy load that completely absorbs microwaves is provided instead of the sliding short that totally reflects microwaves, the energy of microwaves that can be received in order from the plasma generating nozzles on the front end side to the plasma generating nozzles on the rear end side decreases. As a result, the difference between the maximum and minimum becomes larger than when the sliding short is used.

  An object of the present invention is to provide a plasma generator capable of performing uniform plasma irradiation from each plasma generation nozzle while improving the utilization efficiency of microwaves, and a work processing apparatus using the plasma generator.

  The plasma generator of the present invention comprises a microwave generating means for generating a microwave, a waveguide for propagating the microwave with the microwave generating means attached to a starting end, and a plurality of the waveguides. A plasma comprising a plasma generating nozzle that is attached to each other in the direction of propagation of microwaves, receives the microwaves, and generates and emits plasma gas based on the energy of the microwaves The generation device includes a termination member that is provided at a termination portion of the waveguide and includes a combination of an absorber that absorbs the microwave and a reflector that reflects the microwave.

  According to the above configuration, in the plasma generator configured to propagate the microwave from the microwave generating means to the plurality of plasma generating nozzles via the waveguide, the microwave generating means is attached to the start end portion thereof. In the present invention, the end portion of the waveguide is provided with a dummy load that totally absorbs microwaves that have not been absorbed by the respective plasma generation nozzles or a reflection member that totally reflects microwaves. And the terminating member is configured to use a combination of an absorbing material that absorbs microwaves and a reflecting material that reflects.

  Therefore, waste of microwaves can be suppressed. Further, it is possible to prevent the microwave energy received by each plasma generation nozzle from becoming unbalanced due to excessive reflection (returning) of the microwave. In this way, uniform plasma irradiation can be performed from each plasma generation nozzle while increasing the utilization efficiency of the microwave.

  In the plasma generating apparatus of the present invention, the absorbing material comprises a dummy load including a tubular body that traverses the waveguide space in the waveguide, and water filled in the tubular body.

  According to the above configuration, water can absorb microwaves with extremely high efficiency. For this reason, as the absorbing material, a tube that crosses the waveguide space in the waveguide and the tube are filled. By using a dummy load including water, microwaves can be absorbed with high efficiency. As the tube material, glass or resin that absorbs less microwaves can be used, and water boils so as not to affect the absorption depending on the microwave energy to be absorbed. It is only necessary to maintain a temperature at such a level that it does not occur. When the amount of absorption is large, running water may be used.

  Furthermore, in the plasma generating apparatus of the present invention, the reflecting material is a conductive member that protrudes from the outer side of the waveguide to the inner waveguide space and can adjust the amount of protrusion and depression. Features.

  According to the above configuration, for example, a bolt screwed through the wall surface from the outer side to the inner side of the waveguide can be used as the reflecting material. By adjusting the screwing amount, the waveguide in the waveguide can be adjusted. It is possible to adjust the amount of appearing and appearing in space (that is, the amount of reflected microwaves). In that case, preferably, a winding spring is interposed between the head of the bolt and the wall surface on the outer side of the waveguide, so that the bolt that receives the microwave and the waveguide that is at the ground potential. The bolt can be prevented from rattling with the tube to ensure electrical contact and prevent sparks from occurring.

  In the plasma generator of the present invention, the reflecting material is arranged offset from the tube axis center of the waveguide.

  According to the above configuration, the reflecting material is arranged to be offset from the tube axis center of the waveguide, so that the influence on the microwave that reaches the terminal side of the waveguide (reflection ratio) , And the change in the reflection amount due to the adjustment of the amount of the reflection material in the waveguide can be reduced, that is, the change in the reflection amount can be made insensitive (finely adjustable).

  The workpiece processing apparatus of the present invention further 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 in the plasma generating apparatus. And performing a predetermined treatment by irradiating the workpiece with plasma.

  According to the above configuration, a plurality of plasma generating nozzles are provided in the waveguide, and the moving means for relatively moving the plasma generating nozzles and the workpiece are provided, and the workpiece is conveyed while conveying the workpiece to be processed. A workpiece processing apparatus capable of performing uniform plasma irradiation from each plasma generating nozzle while improving the utilization efficiency of microwaves in a workpiece processing apparatus that continuously irradiates plasma with predetermined processing. Can be realized.

  As described above, the plasma generator of the present invention is the plasma generator in which the microwave from the microwave generating means is propagated to the plurality of plasma generating nozzles through the waveguide, and the end of the waveguide. A terminating member is provided in the portion, and the terminating member is configured to use an absorbing material that absorbs microwaves and a reflecting material that reflects.

  Therefore, it is possible to suppress the waste of microwaves and to prevent the microwave energy received by each plasma generation nozzle from being unbalanced due to excessive reflection (returning) of the microwaves. In this way, uniform plasma irradiation can be performed from each plasma generation nozzle while increasing the utilization efficiency of the microwave.

  In addition, as described above, the workpiece processing apparatus of the present invention includes a moving unit that moves the workpiece and the plasma generating nozzle relative to each other on a plane that intersects the plasma irradiation direction. While performing the relative movement, the workpiece is irradiated with plasma to give a predetermined treatment.

  Therefore, it is possible to realize a work processing apparatus that can perform uniform plasma irradiation from each plasma generation nozzle while improving the utilization efficiency of microwaves.

  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 generating unit PU (plasma generating apparatus) that generates plasma and irradiates the workpiece W as a workpiece 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 conveyed by. 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 (starting end) of the waveguide 10. ) Side (left side), a microwave generator 20 that generates microwaves of a predetermined wavelength, a plasma generator 30 provided in the waveguide 10, and the other end (termination) side (right side) of the waveguide 10. A terminating member 40 that is disposed and also reflects and absorbs microwaves moderately, a circulator 50 that separates reflected microwaves from the microwaves emitted to the waveguide 10 so as not to return to the microwave generator 20, and a circulator 50 And a dummy load 60 that absorbs the reflected microwaves separated by the stub tuner 70 for impedance matching between the waveguide 10 and the plasma generating nozzle 31. It has been made. 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 termination member 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. The plasma generating nozzle 31 includes a central conductor 32 (internal conductor), a nozzle body 33 (external conductor), a nozzle holder 34, a seal member 35, and a protective tube 36.

  The center conductor 32 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 vertical direction is such that the lower end 322 is substantially flush with the lower end edge 331 of the nozzle body 33 while penetrating and projecting to the waveguide space 130 by a predetermined length (this projecting portion is referred to as a receiving antenna unit 320). Is arranged. 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 is a cylindrical body made of a highly conductive metal and having a cylindrical space 332 that houses the central conductor 32. The nozzle holder 34 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 holding space 342 that holds the seal member 35. It is a state. 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 functions as an external conductor disposed around the central conductor 32. The central conductor 32 is a cylindrical space with a predetermined annular space H (insulation interval) secured around it. It is inserted on the central axis of 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 (not shown in FIG. 5) is made of a quartz glass pipe or the like having a predetermined length, and has an outer diameter 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.

  The terminating member 40 is provided to make the received microwave energy uniform in the receiving antenna section 320 of each plasma generating nozzle 31. It should be noted that in this embodiment, each plasma is This is a configuration in which a dummy load 41 that totally absorbs a microwave that has not been absorbed by the generating nozzle and a reflecting member 42 that totally reflects the microwave are used together. FIG. 7 is an exploded perspective view of the termination member 40. The dummy load 41, which is an absorbing material, and the reflecting member 42, which is a reflecting material, are provided in the fourth waveguide piece 14 having a flange 141 coupled to the third waveguide piece, and the fourth guide. The terminal end side of the wave tube piece 14 is closed by an end plate 142.

  The dummy load 41 is inserted between the cooling water circulation ports 143 formed in the pair of front and rear side walls 14S of the fourth waveguide piece 14 and traverses the waveguide space 140 in the fourth waveguide piece 14. 411, a base 412 for fixing the tubular body to the side wall 14S, and cooling water supplied into the tubular body 411. A flexible hose is connected to both ends of the tube body 411 fixed to the fourth waveguide piece 14 with a base 412, connected to a pump, tap water faucet, etc., and the cooling water is supplied. Is called. As the material of the tube body 411, glass or resin that absorbs less microwaves can be used, and in this embodiment, flowing water is used as the cooling water. It is only necessary to maintain a temperature that does not boil so as not to affect the absorption according to the microwave energy to be absorbed. When the amount of absorption is small, the tube 411 may be enclosed. In this way, the microwaves not received by each plasma generating nozzle 31 can be absorbed by water with high efficiency, converted into heat, and discharged.

  The reflection member 42 may be a conductive member that protrudes from the outer side of the waveguide to the inner waveguide space and can adjust the amount of protrusion and depression thereof. For example, as shown in FIG. A bolt 421 that can be screwed in from the outer side to the inner side of the upper surface plate 14 </ b> U of the four waveguide pieces 14 and that can adjust the amount of protrusion and withdrawal into the waveguide space 140 can be used. Preferably, a winding spring 422 that prevents rattling of the bolt 421 is interposed between the head portion 4211 of the bolt 421 and the upper surface plate 14U on the outer side of the fourth waveguide piece 14. In this way, the bolt 421 that receives the microwave and the waveguide 10 that is at the ground potential are prevented from rattling of the bolt 421 to ensure electrical contact, and a spark is generated. Can be prevented. The reflection member 42 may be a slide type whose amount of protrusion and depression can be adjusted, and the shape may be a columnar shape, a prismatic shape, a plate shape, or the like.

  In addition, it is preferable that the amount of protrusion and disengagement of the bolt 421 can be automatically adjusted. Specifically, as shown in FIG. 7, as the reflecting member 42, a motor 423 that rotationally drives the bolt 421, and a coupler 424 that connects an output shaft 4231 of the motor 423 and a head portion 4211 of the bolt 421. The encoder 425 for detecting the amount of rotation of the motor 423, that is, the amount of protrusion / depression of the bolt 421 in the waveguide space 140, is housed and fixed on the upper surface plate 14U of the fourth waveguide piece 14. And an outer mantle 426.

  The coupler 424 is connected to a cylindrical portion 4242 having a cylindrical hole 4241 into which the output shaft 4231 of the motor 423 is fitted, and a cylindrical portion 4244 having a hexagonal columnar hole 4243 into which the head portion 4211 of the bolt 421 is fitted. Has been configured. Then, after the bolt 421 is inserted into the winding spring 422 and screwed into the upper surface plate 14U so that the amount of protrusion and withdrawal into the waveguide space 140 becomes a specified length, the output of the motor 423 is inserted into the hole 4241 of the coupler 424. The shaft 4231 is fitted and fixed with a screw 4245. The motor 423 is accommodated in the outer cannula 426 and fixed to a predetermined height, and then the head 4221 of the bolt 421 is fitted into the hole 4243 so that the The flange 4261 of the outer mantle 426 is screwed and fixed to the upper surface plate 14U with screws 4262, whereby the reflecting member 42 capable of adjusting the amount of protrusion and depression is produced.

  The tube body 411 is attached to the central portion in the height direction of the side wall 14S, and the bolt 421 is located on the front side of the tube body 411 from the tube axis center 10Y of the waveguide 10 as shown in FIG. It is arranged with an offset.

  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.

  The dummy load 60 is configured in the same manner as the above-described dummy load 41, and absorbs the above-described reflected microwave by the cooling water supplied into the tube body 61, converts it into heat, and discharges it.

  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. The three stub tuner units 70 </ b> A to 70 </ b> C have the same structure, and as shown in FIG. 3, the stub 71 projecting into the waveguide space 120 of the second waveguide piece 12 is moved up and down in the vertical direction. The power consumption by the conductor 32 is maximized, that is, the reflected microwave is minimized, so that plasma ignition is easily generated.

  The conveyance means C includes a plurality of conveyance rollers C1 arranged along a predetermined conveyance path, and the conveyance roller 80 is driven by an unillustrated driving means, 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. 9 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 motor drive unit 94, a display unit, an operation panel, and the like, an operation unit 95 for providing a predetermined operation signal to the overall control unit 90, and a sensor including an input interface, an analog / digital converter, and the like. An input unit 96, 97, 98, sensors 961, 971, a drive motor 931, a flow rate control valve 923, the motor 423, and the encoder 425 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 generation 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 motor drive unit 94 rotates the motor 423 in both forward and reverse directions.

  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, the rotation angle of the motor 423 by the encoder 425 input from the sensor input unit 98, and the like are monitored. The flow control unit 92, the conveyance control unit 93, and the motor drive unit 94 are controlled 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. The size of the plume P can be controlled by controlling the microwave power and the processing gas flow rate, and the irradiation amount of the plume P can be controlled by controlling the conveyance speed. In this way, a plurality of workpieces W are continuously processed.

  At this time, it should be noted that when switching the conveyance speed of the workpiece W, the CPU 901 drives the motor 423 along with the flow rate of the processing gas to change the amount of the bolt 421, and switches the amount of reflected microwaves. It is.

  As described above, in the present embodiment, when the waveguide 10 is used for microwave propagation to the plurality of plasma generating nozzles 31, the termination member 40 is provided at the end of the waveguide 10, and the termination member 40 is Since the dummy load 41 for absorbing microwaves and the reflecting member 42 for reflecting are used in combination, waste of microwaves can be suppressed by the reflecting member 42 first, and then the reflecting of the microwave by the reflecting member 42 can be suppressed. It is possible to prevent the microwave energy received by each plasma generation nozzle 31 from becoming unbalanced due to excessive (return). In this way, uniform plasma irradiation can be performed from each plasma generating nozzle 31 while improving the utilization efficiency of the microwave. Further, by adjusting the amount of microwave reflected by the reflecting member 40 and the amount of microwave absorbed by the dummy load 41 in accordance with the conveyance speed of the workpiece W, that is, the amount of plasma irradiation, more uniform plasma irradiation. It can be performed.

  Furthermore, by disposing the bolt 421 offset from the tube axis center 10Y of the waveguide 10, the influence (the ratio of reflection) to the microwave that reaches the terminal side of the waveguide 10 is reduced. It is possible to reduce the change in the reflection amount due to the adjustment of the amount of appearance of the bolt 421, that is, to make the change in the reflection amount insensitive (to allow fine adjustment).

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. It is possible to interpose a waveguide containing the.
(5) In the above embodiment, the bolt 421 is used as the reflection member 40 with a variable reflection amount, and the reflection amount is adjusted by the amount of protrusion and depression to the waveguide space 140. For example, an elliptical column is used, The amount of reflection may be adjusted by changing the angle of the pillar, that is, by changing the projected area of the microwave. Although a plate-like member may be moved up and down, a rod-like member such as the bolt 421 or an elliptical column is preferable because it can obtain appropriate reflection as compared with the plate-like member. Further, it is desirable that the reflecting member 40 does not have a sharp edge.
(6) In the above-described embodiment, the amount of reflection is adjusted by continuously adjusting the amount of protrusion / disengagement of the bolt 421 by the motor 423. However, a plurality of rod-shaped members can be protruded and retracted in the waveguide space 140, Alternatively, or in combination, the amount of reflection may be adjusted by switching between projecting with a solenoid or the like, or immersing them (however, the rod-shaped member may be adjusted with a ground wire. It is necessary to take measures against the sparks such as connecting with the waveguide piece).

  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 disassembled perspective view of a termination | terminus member. It is a top view for demonstrating the arrangement position of the volt | bolt which is a reflection member in the said termination | terminus member. It is a block diagram which shows the control system of a workpiece | work processing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Waveguide 20 Microwave generator 30 Plasma generating part 31 Plasma generating nozzle 32 Central conductor 320 Reception antenna part 33 Nozzle main body 34 Nozzle holder 40 Termination member 41, 60 Dummy load 411 Tubing body 42 Reflecting member 421 Bolt 422 Winding spring 423 Motor 424 Coupler 425 Encoder 50 Circulator 70 Stub tuner 80 Conveying roller 90 Overall control unit 901 CPU
902 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 94 Motor drive unit 95 Operation units 96, 97, 98 Sensor input unit 961 Flow rate Sensor 971 Speed sensor S Work processing unit PU Plasma generation unit C Conveying means W Workpiece

Claims (5)

Microwave generating means for generating a microwave, a waveguide for propagating the microwave with the microwave generating means attached to a starting end, and a plurality of the waveguides in the propagation direction of the microwave. In a plasma generator comprising: a plasma generating nozzle that is mounted at intervals, receives the microwave, and generates and discharges a plasma gas based on the energy of the microwave;
A plasma generating apparatus comprising: a termination member provided at a termination portion of the waveguide, wherein the termination member is formed by combining an absorbing material that absorbs the microwave and a reflecting material that reflects the microwave.   2. The plasma generating apparatus according to claim 1, wherein the absorbing material comprises a dummy load including a tube that crosses the waveguide space in the waveguide and water filled in the tube.   3. The plasma according to claim 1, wherein the reflecting material is a conductive member that protrudes from an outer side of the waveguide to an inner waveguide space and that can adjust an amount of protrusion and depression. 4. Generator.   The plasma generating apparatus according to claim 3, wherein the reflecting material is disposed offset from a tube axis center of the waveguide.   The plasma generation apparatus according to any one of claims 1 to 4, further comprising a moving unit that relatively moves the workpiece and the plasma generation nozzle on a surface that intersects the plasma irradiation direction. A workpiece processing apparatus for performing predetermined processing by irradiating the workpiece with plasma while performing a smooth movement.

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