JP2007265829A - Plasma generator and work processing device using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma generator used in processing of a work such as reforming of a substrate which can cope with the work with arbitrary height and the work with steep irregularity. <P>SOLUTION: Coaxial cables 381 having flexibility are interposed between a waveguide 10 and plasma generating nozzles 31 in propagating microwave generated by the microwave generator 20 to the plasma generating nozzles 31 through the waveguide 10. Thereby, the plasma generating nozzle 31 portion is made small in size and freedom in handling can be improved, and therefore, by mounting the plasma generating nozzles 31 on a robot arm, uniform plasma irradiation can be made on the work W with irregularity caused by electronic components W2. <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

  However, the above-described conventional technology only shows the structure of the plasma generating nozzle, and it is possible to obtain a uniform (density) on a workpiece of any height or a rugged workpiece such as an electronic component to be mounted. There is a problem that it is impossible to conceive whether plasma irradiation can be performed.

  The objective of this invention is providing the workpiece processing apparatus which can respond | correspond to the workpiece | work of arbitrary heights, or a workpiece | work with severe unevenness | corrugations.

  The plasma generation apparatus of the present invention propagates the microwave generated by the microwave generation means to the plasma generation nozzle through the waveguide, and the plasma generation gas is converted into plasma based on the energy received by the plasma generation nozzle. In the plasma generating apparatus that generates and emits, the microwave feeding member having flexibility is interposed between the waveguide and the plasma generating nozzle.

  According to the above configuration, the microwave generated by the microwave generation means is propagated to the plasma generation nozzle via the waveguide, and the plasma generation gas is generated based on the microwave energy received by the plasma generation nozzle. In the plasma generating apparatus, the microwave feeding member having flexibility such as a coaxial cable is interposed between the waveguide and the plasma generating nozzle.

  Therefore, by reducing the size of the plasma generating nozzle part and improving the degree of freedom of handling, it is possible to deal with workpieces of any height or workpieces with severe irregularities.

  In the plasma generator of the present invention, the power supply member is a coaxial cable.

  According to said structure, energy transmission can be performed efficiently using a general purpose product.

  Furthermore, the plasma generator of the present invention includes an impedance adjusting member that is disposed opposite to the coaxial cable in the waveguide and adjusts the impedance of the waveguide by changing an inner peripheral length of the waveguide. It is characterized by providing.

  According to the above configuration, when the flexible microwave feeding member is realized by a coaxial cable, the cross-section orthogonal to the microwave transmission direction in the waveguide is opposed to the coaxial cable. An impedance adjusting member capable of adjusting the impedance of the waveguide by changing the inner peripheral length is provided.

  Therefore, it is possible to reduce the impedance deviation between the waveguide and the coaxial cable, reduce the reflection and loss of microwaves, and cope with the change in impedance due to the replacement of the coaxial cable and the plasma generating nozzle.

  In the plasma generating apparatus of the present invention, a power supply member corresponding to each of a plurality of plasma generating nozzles is connected to the waveguide.

  According to the above configuration, when a plurality of plasma generating nozzles are driven by one microwave generating means, the power supply members are sequentially attached in the longitudinal direction of the waveguide. The microwave energy received varies depending on the standing wave pattern and the like.

  Therefore, the present invention that can adjust the balance for each of the plurality of plasma generating nozzles is particularly suitable.

  Furthermore, a workpiece processing apparatus according to the present invention is characterized by using the plasma generator.

  According to said structure, the workpiece | work processing apparatus which can respond | correspond to the workpiece | work of arbitrary height or a workpiece | work with severe unevenness | corrugation can be implement | achieved.

  The workpiece processing apparatus of the present invention is characterized in that the plasma generating nozzle is attached to the tip of a robot arm.

  According to the above configuration, the plasma generating nozzle that is small in size and has a high degree of freedom of handling as described above is suitable for being attached to the tip of the robot arm. It is possible to deal with workpieces having complicated shapes, and processing can be performed without moving the workpiece.

  As described above, the plasma generating apparatus of the present invention propagates the microwave generated by the microwave generating means to the plasma generating nozzle through the waveguide, and based on the energy of the microwave received by the plasma generating nozzle. In the plasma generator configured to generate and discharge plasma gas, the flexible microwave feeding member such as a coaxial cable is interposed between the waveguide and the plasma generating nozzle.

  Therefore, by reducing the size of the plasma generating nozzle part and improving the degree of freedom in handling, it is possible to deal with workpieces of any height or workpieces with severe irregularities.

  In addition, as described above, the work processing apparatus of the present invention uses the plasma generator.

  Therefore, it is possible to realize a workpiece processing apparatus that can cope with a workpiece having an arbitrary height or a workpiece having severe irregularities.

  Furthermore, the workpiece processing apparatus of the present invention is characterized in that the plasma generating nozzle is attached to the tip of a robot arm.

[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 nozzle 31 that generates plasma and irradiates the workpiece W as a workpiece with the plasma, a microwave generation unit 1 that applies microwaves to the plasma generation nozzle 31, and the plasma. A robot arm 80 that realizes plasma irradiation by displacing the generating nozzle 31 to an arbitrary position on the workpiece W placed on the irradiation table 110, and a gas supply system 90 that supplies a processing gas to the plasma generating nozzle 31. It is configured with. 2 is a perspective view of the microwave generator 1 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 microwave generation unit 1 generally includes a waveguide 10 that propagates microwaves, a microwave generator 20 that is disposed on one end side (left side) of the waveguide 10 and generates microwaves of a predetermined wavelength, and a waveguide. A microwave distributor 30 provided in the wave tube 10, a sliding short 40 disposed on the other end side (right side) of the waveguide 10 to reflect the microwave, and a reflected micro wave among the microwaves emitted to the waveguide 10. Impedance matching between the circulator 50 that separates the wave so as not to return to the microwave generator 20, the dummy load 60 that absorbs the reflected microwave separated by the circulator 50, and the waveguide 10 and the receiving antenna in the microwave distributor 30. A stub tuner 70 is provided to achieve this. On the irradiation stand 110 installed at a fixed position, a workpiece W having unevenness is mounted by mounting an electronic component W2 on a substrate W1.

  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 microwave distributor 30 in the longitudinal direction thereof. It is something to be made. 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 microwave distributor 30 are connected to each other. 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 microwave generation unit 1 according to the present embodiment, a continuously variable microwave generator 20 that can output microwave energy of 1 W to 3 kW, for example, 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 microwave distribution unit 30 includes four receiving antennas 38 that are arranged in a line in the left-right direction on the upper surface plate 13U of the third waveguide piece 13, and the receiving antenna 38 on the lower surface plate 13B. An impedance adjusting member 39 is provided so as to face each other. It is desirable that the arrangement interval of the four receiving antennas 38 be determined according to the wavelength λ _{G of the} microwave propagating in the waveguide 10. For example, it is desirable to arrange the receiving antennas 38 at a ½ pitch and a ¼ pitch of the wavelength λ _{G. When} a microwave of 2.45 GHz is used, λ _G = 230 mm, so 115 mm (λ _G / 2) The receiving antennas 38 may be arranged at a pitch or 57.5 mm (λ _G / 4) pitch. The receiving antenna 38 is connected to the plasma generating nozzle 31 through a coaxial cable 381 that is a flexible microwave feeding member.

  4 is a cross-sectional view taken along the section line AA of FIG. In the microwave distributor 30, a plug 131 is attached to the upper surface plate 13 U of the third waveguide piece 13 at the receiving antenna 38, and the coaxial cable 381 is connected to one end thereof. The plug 382 is screwed onto the plug 131 so that power can be supplied. A general-purpose product can be used for the coaxial cable 381 and the plug 382. The inner conductor 3811 of the coaxial cable 381 enters the waveguide space 130 of the third waveguide piece 13 from the connector 131 and becomes the receiving antenna 38. The outer conductor 3812 of the coaxial cable 381 is connected to the ground potential from the plugs 382 and 131 through the third waveguide piece 13. Note that a member different from the inner conductor 3811 of the coaxial cable 381 may be used for the receiving antenna 38, and input may be performed so that they are electrically connected in the plug 131.

  A rectangular hole 132 having a microwave propagation direction as a longitudinal direction is formed in the lower surface plate 13 </ b> B of the third waveguide piece 13 so as to face the receiving antenna 38. The impedance adjusting member 39 can appear and disappear in the wave space 130. As shown in FIG. 3, the impedance adjusting member 39 has a generally mountain-shaped cross section in the microwave propagation direction. At the top of the impedance adjusting member 39 is a tip 380 of the receiving antenna 38 as shown in FIG. A hole 390 is formed to fit in sliding contact. The impedance adjusting member 39 forms part of the lower surface plate 13B of the third waveguide piece 13 and is made of the same nonmagnetic metal. Then, the tip 380 of the receiving antenna 38 is fitted into the hole 390 in sliding contact as described above, so that the receiving antenna 38 can receive high-frequency microwaves as described above without causing discharge between them. It has become.

  Further, in the microwave distribution unit 30, the receiving antenna 38 is provided with a displacement means for causing the impedance adjusting member 39 to appear in and out of the waveguide space 130 on one side plate 13 </ b> H of the third waveguide piece 13. 391 is provided. The displacement means 391 includes a base 392 attached to the side plate 13H of the third waveguide piece 13, a moving member 393 to which the impedance adjusting member 39 is attached, and an elevating mechanism 395 for raising and lowering the moving member 393. It is prepared for.

  The elevating mechanism 395 includes a motor 3951, a worm gear 3953 fixed to the output shaft 3952 of the motor 3951, a gear 3954 in which the worm gear 3953 meshes with external teeth, one end fixed to the moving member 393, and the other end side And a ball screw 3955 that meshes with the internal teeth of the gear 3954. These elevating mechanisms 395 are housed in a gear box composed of the base body 391. When the motor 3951 rotates, the moving member 393, and hence the impedance adjusting member 39, is displaced up and down. Other configurations such as a linear motor and an air cylinder may be used for the lifting mechanism 395.

  The robot arm 80 includes a base 801 installed around the irradiation table 110, an arm 802 having a base connected to the base 801, and a head 803 attached to the free end of the arm 802. Is done. The coaxial cable 381 and the gas supply pipe 91 in the gas supply system 90 are provided on the inner side or the outer side of the arm 802 and the head 803 from the base 801, separately from the drive line and the sensing line for driving and displacing the arm 802 and the head 803. Is laid. The arm 802 and the head 803 have arbitrary degrees of freedom and can displace the plasma generating nozzle 31 to an arbitrary position on the irradiation table 110.

  FIG. 5 is an enlarged view showing the plasma generating nozzle 31. The plasma generation nozzle 31 is a nozzle that can generate plasma at normal temperature and normal pressure using microwaves as in the above-described Patent Document 1. The plasma generating nozzle 31 includes a central conductor 32 that is an inner electrode, a nozzle body 33 and a nozzle holder 34 that are outer electrodes, a seal member 35, a protective tube 36, and a gas seal ring 37. The

  The central conductor 32 is made of a highly conductive metal such as copper, aluminum, or brass, and is composed of a rod-shaped member having a diameter of about 1 to 5 mm. A plug 383, which is a spring-like inner conductor and is attached to the other end of the coaxial cable 381, is screwed to the plug 804, thereby being electrically connected to the inner conductor 3811, so that the microwave can be fed. It becomes possible. The outer conductor 381 of the coaxial cable 381 is electrically connected to the nozzle main body 33 from the nozzle holder 34 through the plug 383 through the plug 804, so that the nozzle main body 33 is at the ground potential.

  The lower end portion 322 of the central conductor 32 is arranged in the vertical direction so that the tip 3221 thereof is substantially flush with the lower end edge 331 of the nozzle body 33. The central conductor 32 is also 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 that is tightly fitted into a through hole 805 drilled in the head 803, and a lower body portion 34B that extends downward from the head 803. 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 the gas supply pipe 91 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. In the upper body portion 34U of the nozzle holder 34, the plug 804 is formed on the upper side of the upper holding space 342.

  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 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 generating nozzle 31 being configured as described above, the nozzle body 33, the nozzle holder 34, the outer conductor 3812 of the coaxial cable 381, and the waveguide 10 are in a conductive state (the same potential), while the center Since the conductor 32 is supported by the insulating seal member 35, it is electrically insulated from these members. Therefore, as shown in FIG. 4, the microwave is received by the receiving antenna 38 in a state where the waveguide 10 is at the ground potential, and the microwave power is transmitted from the inner conductor 3811 of the coaxial cable 381 to the central conductor 32. When power is supplied, 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.

  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 sliding short 40 is provided for optimizing the coupling state between each receiving antenna 38 and the microwave propagated inside the waveguide 10, and changes the reflection position of the microwave. It is connected to the right end of the third waveguide piece 13 so that the standing wave pattern can be adjusted. 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. 6 is a perspective view showing the internal structure of the sliding short 40. As shown in FIG. 6, 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 microwave distributor 30, power is not consumed by the microwave distributor 30. The reflected microwave returning 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. 7 is a top view of the microwave generation unit 1 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 12, 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 53 and incident on the dummy load 60 as indicated by the 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. 8 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.

  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 an overall control unit 100 including a CPU (central processing unit) 101 and its peripheral circuits, a microwave output control unit 104 including an output interface and a drive circuit, a gas flow rate control unit 105, and arm control. Unit 106, a display means, an operation panel, and the like, an operation unit 107 for giving a predetermined operation signal to the overall control unit 100, and sensor input units 108, 109 including an input interface, an analog / digital converter, and the like. And is configured.

  The microwave output control unit 104 performs ON / OFF control and output intensity control of the microwave output from the microwave generation device 20. The microwave output control unit 104 generates the 2.45 GHz pulse signal and outputs the pulse signal of the microwave generation device 20. The operation control of the microwave generation by the apparatus main body 21 is performed. The gas flow rate control unit 105 controls the flow rate of the processing gas supplied to each plasma generation nozzle 31. Specifically, opening / closing control or opening degree adjustment of the flow rate control valve 93 provided in the gas supply pipe 91 connecting the processing gas supply source 92 such as a gas cylinder and each plasma generation nozzle 31 is performed. The arm control unit 106 controls the operation of the robot arm 80.

  The overall control unit 100 is responsible for overall operation control of the work processing apparatus S. The measurement result of the flow rate sensor 94 input from the sensor input unit 108 according to the operation signal given from the operation unit 107, the sensor The detection result of the encoder or potentiometer of the robot arm 80 input from the input unit 109 is monitored, and the microwave output control unit 104, the gas flow rate control unit 105, and the arm control unit 106 are based on a predetermined sequence. Control the operation.

  Specifically, the CPU 101 starts the movement of the robot arm 80 based on a control program stored in advance in the memory 102 and guides the plasma generating nozzle 31 to the irradiation position on the workpiece W, thereby processing the predetermined flow rate. A plasma (plume P) is generated by supplying microwave power while supplying gas to each plasma generating nozzle 31, and the plume P is radiated on the surface of the robot arm 80 while moving. As a result, one or a plurality of workpieces W with severe irregularities are continuously processed.

  At this time, the CPU 101 determines the height and position of the plasma generating nozzle 31 detected by the sensor in the robot arm 80 and the height at each position of the workpiece W stored in advance in the memory 103 from teaching and design drawing data. The robot arm 80 is driven, and the plasma generating nozzle 31 is moved to the next irradiation position and the height corresponding to the position.

  According to the workpiece processing apparatus S described above, when the microwave generated by the microwave generation apparatus 20 is propagated to the plasma generation nozzle 31 via the waveguide 10, the waveguide 10 and the plasma generation nozzle 31 Since a flexible coaxial cable 381 is interposed between them, the structure of the plasma generating nozzle 31 is reduced in size and the degree of freedom in handling is improved, so that a workpiece of any height or a workpiece with severe irregularities can be obtained. W can be supported.

  Further, since the work processing apparatus S is configured by being attached to the tip of the robot arm 80 using the plasma generation nozzle 31 that is highly miniaturized (for example, 500 g or less) and has a high degree of freedom in handling, the work processing apparatus S can be handled up to now. It is possible to deal with a workpiece W having a complicated shape that has not been present, and it is possible to perform processing without moving the workpiece W.

  Although Patent Document 1 also describes the use of a coaxial cable as a feeder line, it is not a combination with a waveguide as in the present invention, but is a single coaxial cable. Here, in the plasma generation nozzle 31, when the plasma (plume P) is lit (ignited), during the period from when the microwave is applied until it is actually lit (ignited), the applied microwave is generated by the plasma. The light is reflected at the tip of the nozzle 31. Therefore, when the antenna is directly connected to the microwave generator via a coaxial cable as in Patent Document 1, the reflected wave is incident on the microwave generator, whereas it is guided as in the present invention. When the tube 10 is interposed, the reflected microwave is consumed by the dummy load 60 or the like and does not return to the microwave generator 20. As a result, the life of the plasma generation unit PU can be extended.

  Furthermore, in the work processing apparatus S of the present embodiment, by changing the inner circumferential length L (see FIG. 4) of the waveguide 10 so as to face the coaxial cable 381 in the waveguide 10. Since the impedance adjusting member 39 for adjusting the impedance of the waveguide 10 is provided, the impedance deviation between the waveguide 10 and the coaxial cable 381 can be reduced, the reflection and loss of the microwave can be reduced, and the coaxial It is possible to cope with a change in impedance due to replacement of the cable 381 and the plasma generation nozzle 31. Specifically, the coaxial cable 381 changes the thickness, length, material, and the like, and the plasma generating nozzle 31 changes the outer diameter of the central conductor 32, the inner diameter of the nozzle body 33, and changes of those materials. In order to reduce the impedance in response to these changes, the motor 3951 of the elevating mechanism 395 is driven so that the inner circumferential length L is increased, that is, the impedance adjusting member 39 protrudes into the waveguide space 130. do it. Whether or not the impedance is matched can be determined from whether or not the plasma (plume P) is lit or the microwave energy consumed by the plasma generation nozzle 31.

  The impedance adjusting member 39 may not be formed in a slope shape with respect to the propagation direction of the microwave, and even if a part of the lower surface plate 13B of the third waveguide piece 13 is moved up and down, The inner circumferential length L can be changed. However, reflection and absorption at the end face can be suppressed by forming the slope shape.

  Furthermore, in the workpiece processing apparatus S of the present embodiment, the waveguide 10 is provided in the longitudinal direction of the waveguide 10 in order to drive a plurality of plasma generation nozzles 31 by one microwave generator 20. Since the coaxial cables 381 are sequentially attached, the energy of the microwaves received by the corresponding receiving antennas 38 varies depending on the standing wave pattern or the like, whereas the balance adjustment can be performed by the impedance adjusting member 39 as described above. It is particularly suitable to do.

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, 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.
(2) 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.
(3) When the robot arm 80 is driven, the geometry data of the workpiece W, that is, the map information of the position and height of the electronic component W2, is previously determined and stored in the memory 103 from the teaching and design drawing data as described above. Instead, the robot arm 80 may be driven while measuring the height of the electronic component W2 at the next irradiation position in contact or non-contact.
(4) In the above embodiment, the impedance adjustment member 39 is caused to appear and disappear in the waveguide space 130 to cope with a change in impedance due to the replacement of the coaxial cable 381 and the plasma generating nozzle 31. For example, in FIG. As shown, a ridge 135 having a mountain shape may be formed over substantially the entire length of the lower surface plate 13B ′ of the third waveguide piece 13 ′ to serve as an impedance adjustment member. In this case, the coaxial cable 381 may be connected to one of the plurality of plugs 131 that matches the impedance.

  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. It is a perspective view of the microwave generator which made the line-of-sight direction different from FIG. It is a partial see-through | perspective side view of a workpiece | work processing apparatus. It is sectional drawing seen from the cut surface line AA of FIG. It is a figure which expands and shows 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 microwave 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 figure for demonstrating the technique of the impedance adjustment which concerns on other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Microwave generation unit 10 Waveguide 13 3rd waveguide piece 130 Waveguide space 131,382,383,804 Plug 20 Microwave generator (microwave generation means)
30 Microwave distributor 31 Plasma generating nozzle 32 Central conductor 33 Nozzle body 34 Nozzle holder 344 Gas supply hole 38 Receiving antenna 381 Coaxial cable 3811 Inner conductor 3812 Outer conductor 39 Impedance adjusting member 391 Displacement means 393 Moving member 395 Lifting mechanism 3951 Motor 40 Sliding short 50 Circulator 60 Dummy load 70 Stub tuner 80 Robot arm 801 Base 802 Arm 803 Head 90 Gas supply system 91 Gas supply pipe 100 Overall control unit 101 CPU
102, 103 Memory 104 Microwave output control unit 105 Gas flow rate control unit 106 Arm control unit 107 Operation unit 108, 109 Sensor input unit 110 Irradiation table S Work processing device W Work W1 Substrate W2 Electronic component

Claims (6)

Propagation of the microwave generated by the microwave generation means to the plasma generation nozzle through the waveguide, and the plasma generation nozzle generates and releases plasma gas based on the energy received by the microwave In the device
A plasma generating apparatus, wherein the microwave power supply member having flexibility is interposed between the waveguide and the plasma generating nozzle.   The plasma generating apparatus according to claim 1, wherein the power supply member is a coaxial cable.   The impedance adjustment member which adjusts the impedance of the said waveguide by changing the inner peripheral length of this waveguide, and is arrange | positioned facing the said coaxial cable in the said waveguide, It is characterized by the above-mentioned. Plasma generator.   The plasma generator according to any one of claims 1 to 3, wherein a power supply member corresponding to each of a plurality of plasma generation nozzles is connected to the waveguide.   The workpiece processing apparatus using the plasma generator of any one of the said Claims 1-4.   6. The workpiece processing apparatus according to claim 5, wherein the plasma generating nozzle is attached to a tip of a robot arm.

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