Abstract:
A plasma processor with a microwave generating source mounted integrally on a shield lid by miniaturizing a matching circuit. The plasma processor is characterized by comprising a evacuatable processing vessel ( 42 ), a workpiece mount base ( 44 ) provided in the processing vessel, a microwave transmitting plate ( 70 ) provided in the opening section of the top of the processing vessel, a plane antenna member ( 74 ) for supplying a microwave into the processing vessel via the microwave transmitting plate, a shield lid ( 78 ) so grounded as to cover the top of the plane antenna member, a waveguide ( 82 ) for guiding the microwave from a microwave generating source to the plane antenna member, a member elevating mechanism ( 85 ) for relatively varying the vertical distance between the plane antenna member and the shield lid, a tuning rod ( 104 ) so provided insertably into the waveguide tube, a tuning rod drive mechanism ( 102 ) so moving the tuning rod as to adjust its insert amount, and a matching control section ( 114 ) for matching adjustment by controlling the elevation amount of the antenna member and the insert amount of the tuning rod.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a plasma processing apparatus for processing a semiconductor wafer and the like by applying thereon a plasma generated by a microwave.  
       BACKGROUND OF THE INVENTION  
       [0002]     Along with a recent trend of a high density and a high miniaturization of semiconductor devices, a plasma processing apparatus is used for performing a film forming process, an etching process, an ashing process and the like in a manufacturing process of the semiconductor devices. Especially, since a plasma can be stably generated in an environment at a high vacuum level in which a pressure is comparatively low, e.g., ranging from 0.1 to several tens mTorr, a plasma processing apparatus for processing a wafer by using a high-density plasma generated by a microwave tends to be used.  
         [0003]     Such plasma processing apparatus is disclosed in Japanese Patent Laid-Open Publication Nos. 3-191073 and 5-343334 or Japanese Patent Laid-Open Publication No. 9-181052 filed by the applicant of the present invention. Herein, a conventional plasma processing apparatus using a microwave will be schematically described with reference to  FIG. 9 .  FIG. 9  shows a view illustrating a conventional typical plasma processing apparatus.  
         [0004]     Referring to  FIG. 9 , there is illustrated a plasma processing apparatus  2  having a workpiece mount base  6  for mounting thereon a semiconductor wafer W in an evacuatable processing vessel  4 . Further, hermetically provided on a ceiling portion facing the workpiece mount base  6  is a microwave transmitting window  8 , made of, e.g., disc-shaped aluminum nitride and the like, for transmitting a microwave. Specifically, the microwave transmitting window  8  is hermetically installed via a sealing member  14  such as an O-ring and the like on a supporting bracket  12  protruded inwardly along a radial direction of a ring-shaped supporting frame member  10 , wherein the supporting frame member  10  made of, e.g., aluminum, is installed at an upper portion of the processing vessel  4 .  
         [0005]     Further, provided on a top surface of the microwave transmitting window  8  are a disc-shaped planar antenna member  16  having a thickness of several mm and a wave-delay member  18 , if necessary, made of, e.g., a dielectric material, for shortening a wavelength of the microwave along a radial direction of the planar antenna member  16 . A shield lid  19  made of a conductor is used for covering top portions of the planar antenna member  16  and the wave-delay member  18  and blocking a top portion of the processing vessel  4 . Moreover, installed above the wave-delay member  18  is a ceiling cooling jacket  22  having therein a cooling water path  20  for allowing cooling water to flow therethrough to cool the shield lid  19  and the like. Besides, formed through the antenna member  16  are microwave radiation holes  24  including a plurality of approximately circular or slit-shaped through-holes. Additionally, an internal conductor  28  of a coaxial waveguide  26  is connected to a central portion of the planar antenna member  16 . The coaxial waveguide  26  is connected to a rectangular waveguide  32  via a mode converter  30 , and the rectangular waveguide  32  is sequentially connected to a matching circuit  34  and a microwave generating source  36 . Accordingly, a microwave of, e.g., 2.45 GHz, generated from the microwave generating source  36  can be guided to the antenna member  16 . The microwave which propagates along a radial direction of the antenna member  16  is emitted through the microwave radiation holes  24  provided in the antenna member  16  toward the microwave transmitting window  8 . Then, the microwave transmitted through the microwave transmitting window  8  is introduced into the processing vessel  4 , thereby generating a plasma in the processing vessel  4  to perform a plasma processing such as an etching, a film formation and the like on a semiconductor wafer W.  
         [0006]     The microwave generating source  36  described above typically generates a high power of about 5 KW and, therefore, the matching circuit  34  for restricting a reflection wave to be generated becomes large. Accordingly, the matching circuit  34  is provided on a floor portion which is located at an outside of a frame of the plasma processing apparatus  2  so that a relatively long rectangular waveguide  32  must be used to connect the matching circuit  34  to the mode converter  30 .  
         [0007]     Maintenance and repairing works of such plasma processing apparatus  2  are regularly or irregularly carried out. At this time, the shield lid  19  or the microwave transmitting window  8  is separated to examine the antenna member  16 , the wave-delay member  18 , a structure in the processing vessel  4  and the like.  
         [0008]     However, in order to separate the shield lid  19  covering the top portion of the processing vessel  4 , the long and large rectangular waveguide  32  connected to the shield lid  19  as one body should be separated by loosening screws and the like (not shown) of a flange portion  32 A. Thus, the maintenance and the repairing works of the plasma processing apparatus  2  become quite complex.  
         [0009]     Further, as described above, since a length of the rectangular waveguide  32  is relatively long, a multiple reflection of the microwave can easily occur therein and further, a load will be increased accordingly to thereby cause a power loss, resulting in deterioration of a power efficiency.  
         [0010]     Since, moreover, a distance between the matching circuit  34  and a plasma becomes as large as several wavelengths, an impedance therebetween becomes overwhelmingly greater in comparison with a plasma impedance of the plasma. Consequently, the plasma impedance is not properly reflected in the matching circuit  34 , so that it is difficult to appropriately control an ignition of the plasma and a stabilization of the plasma by using the matching circuit  34 .  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention has been developed in order to effectively solve the aforementioned drawbacks. Therefore, an object of the present invention is to provide a plasma processing apparatus in which a matching circuit is scaled down such that a microwave generating source and the like can be mounted on a shield lid as one body.  
         [0012]     In accordance with a preferred embodiment of the present invention, there is provided a plasma processing apparatus comprising: an evacuatable processing vessel; a workpiece mount base, installed in the processing vessel, for mounting thereon an object to be processed; a microwave transmitting plate provided in an opening of a ceiling of the processing vessel; a planar antenna member for supplying a microwave into the processing vessel via the microwave transmitting plate; a shield lid grounded to cover a top of the planar antenna member; a waveguide for guiding the microwave from a microwave generating source to the planar antenna member; a member elevating mechanism for relatively varying a vertical distance between the planar antenna member and the shield lid; a tuning rod insertable into the waveguide; a tuning rod driving mechanism for moving the tuning rod to adjust an insert amount thereof; and a matching control section for controlling an elevation amount of the planar antenna member and the insert amount of the tuning rod to obtain a matching adjustment.  
         [0013]     Accordingly, since both the planar antenna member which is moved relatively up and down and the tuning rod whose amount of insertion into the waveguide may be controllable are used to perform a matching function for preventing the reflection wave of the microwave from being generated, the structure of the propagation system of the microwave can be greatly reduced and, accordingly, the propagation system of the microwave, which includes the microwave generating source, can be mounted on the shield lid as a unit.  
         [0014]     As a result, maintenance and repairing works of the plasma processing apparatus can be carried out simply by separating the shield lid from the processing vessel without separating the waveguide and the like. Thus, the maintenance and repairing works thereof can be performed quickly and easily.  
         [0015]     Further, since the length of the waveguide in which the microwave propagates can be shortened, it is possible to suppress the generation of the reflection wave or the power loss, improving a controllability on the plasma by the matching circuit.  
         [0016]     In this case, a reflection wave detecting section for detecting a state of a reflection wave of the microwave is installed in the waveguide at an upstream of the tuning rod.  
         [0017]     The detected state of the detected reflection wave, for example, is represented in terms of a power and a phase.  
         [0018]     The waveguide has, for example, at a middle portion thereof a mode converter for converting a vibration mode of the microwave.  
         [0019]     The waveguide has therein a driving shaft for elevating, for example, the antenna member.  
         [0020]     Further, a plasma processing apparatus in accordance with the present invention includes: an evacuatable processing vessel; a workpiece mount base, installed in the processing vessel, for mounting thereon an object to be processed; a microwave transmitting plate provided in an opening of a ceiling of the processing vessel; a planar antenna member installed above the microwave transmitting plate; a shield lid grounded to cover a top of the planar antenna member; a wave guiding unit for guiding a microwave from a microwave generating source to the planar antenna member; a matching circuit formed by arranging a phase advance element, a phase delay element and a switching device on a printed circuit board between the microwave generating source and the planar antenna member; and a matching control section for switching the switching device to obtain a matching adjustment.  
         [0021]     As described above, since the matching circuit is scaled down by using a printed circuit board, it is possible to greatly reduce a size of a structure of the propagation system of the microwave. Therefore, the propagation system of the microwave, which includes the microwave generating source, can be mounted on the shield lid as a unit.  
         [0022]     As a result, the maintenance and the repair of the plasma processing apparatus can be carried out simply by separating the shield lid from the processing vessel without separating the waveguide and the like. Thus, the maintenance and repairing works thereof can be carried out quickly and easily.  
         [0023]     Further, since the length of the waveguide in which the microwave propagates can be shortened, a generation of the reflection wave of the microwave or a power loss can be avoided.  
         [0024]     In this case, the phase advance element and the phase delay element include microstrip lines, for example.  
         [0025]     Further, the switching device is a PIN diode, for example.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0026]      FIG. 1  shows a plasma processing apparatus in accordance with a first preferred embodiment of the present invention;  
         [0027]      FIG. 2  illustrates a view for explaining an operation of the plasma processing apparatus depicted in  FIG. 1 ;  
         [0028]      FIG. 3  describes a Smith chart for showing a relationship between a reflection coefficient and an impedance when a planar antenna member is elevated;  
         [0029]      FIG. 4  depicts a partially enlarged view of a modified example of a tuning rod;  
         [0030]      FIG. 5  provides a configuration view for showing a plasma processing apparatus in accordance with a second preferred embodiment of the present invention;  
         [0031]      FIG. 6  presents a configuration view for illustrating a plasma processing apparatus in accordance with a third preferred embodiment of the present invention;  
         [0032]      FIG. 7  represents a configuration view of a matching circuit using a printed circuit board;  
         [0033]      FIG. 8  illustrates a phase advance element and a phase delay element formed by using microstrip lines; and  
         [0034]      FIG. 9  sets forth a configuration view for showing a conventional plasma processing apparatus.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0035]     Hereinafter, a preferred embodiment of a plasma processing apparatus in accordance with the present invention will be described in detail with reference to the accompanying drawings.  
         [0036]      FIG. 1  shows a configuration view for illustrating a first preferred embodiment of a plasma processing apparatus in accordance with the present invention, and  FIG. 2  illustrates a view for explaining an operation of the plasma processing apparatus depicted in  FIG. 1 .  
         [0037]     As illustrated in  FIGS. 1 and 2 , a plasma processing apparatus  40  has a cylindrical processing vessel  42 , wherein the processing vessel  42  has a bottom portion made of a conductor, e.g., aluminum, has a totally cylindrical shape, is grounded, and has therein a sealed processing space S.  
         [0038]     The processing vessel  42  has therein a workpiece mount base  44  for mounting thereon, e.g., a semiconductor wafer W, as an object to be processed. The workpiece mount base  44  of an approximately cylindrical shape with a flat top surface is made of alumite-processed aluminum and is protrudently installed. A bottom portion of the workpiece mount base  44  is supported by a cylindrical support  46  made of aluminum and the support  46  is installed at a bottom portion of the processing vessel  42  via an insulating member  48 .  
         [0039]     Installed on the top surface of the workpiece mount base  44  is an electrostatic chuck or a clamp device (not shown) for holding a wafer on the top surface of the workpiece mount base  44 . The workpiece mount base  44  is connected to a high frequency bias power supply  54  of, e.g., 13.56 MHz, by a feeder line  50  via a matching box  52 . In some cases, the high frequency bias power supply  54  may not be installed. Even if the high frequency bias power supply  54  is not installed, a bias electrode grounded or electrically floated can be provided, thereby improving an efficiency of a plasma ignition.  
         [0040]     Provided in the support  46  for supporting the workpiece mount base  44  is a cooling jacket  56  for letting a cooling water to flow therethrough to cool the wafer during a plasma processing. Further, if necessary, the workpiece mount base  44  may have therein a heater.  
         [0041]     Installed on a sidewall of the processing vessel  42  is a gas supply nozzle  58  made of, e.g., a quartz pipe, for introducing a plasma gas, e.g., Ar gas, or a processing gas, e.g., a deposition gas, into the processing vessel  42 . Accordingly, the plasma gas and/or the processing gas with a controlled flow rate thereof can be supplied thereinto through the gas supply nozzle  58 . The deposition gas serving as the processing gas includes SiH 4  gas, O 2  gas, N 2  gas and the like.  
         [0042]     Further, installed on the sidewall of the processing vessel  42  are a gate valve  60  to be opened for loading/unloading the wafer into/from the processing vessel  42  and a cooling jacket  62  for cooling the sidewall of the processing vessel  42 . Moreover, a gas exhaust port  64  connected to a vacuum pump (not shown) is provided in a bottom portion of the processing vessel  42 , so that an inner space of the processing vessel  42  can be evacuated to a certain pressure level.  
         [0043]     In addition, a ceiling portion of the processing vessel  42  is opened to form an opening. A circular ring-shaped supporting frame member  66  is provided along a peripheral portion of the opening via a sealing member  68  such as an O-ring and the like. Hermetically installed on the supporting frame member  66  is a microwave transmitting plate  70  made of a dielectric, e.g., a ceramic material such as AlN and the like with a thickness of about 20 mm, wherein the microwave transmitting plate  70  is transparent to a microwave. Accordingly, the inner space of the processing vessel  42  is kept hermetically sealed.  
         [0044]     Further, provided above the microwave transmitting plate  70  is a disc-shaped planar antenna member  74  whose peripheral portion is detachably supported on a top portion of the supporting member  66 . Installed on a top surface of the antenna member  74  is a higher dielectric disc-shaped wave-delay member  76  having a higher dielectric constant than that of a vacuum. A lid-shaped shield lid  78  is provided to cover both the antenna member  74  and the wave-delay member  76 , and a bottom portion of the shield lid  78  is supported by a top portion of the supporting member  66 . The shield lid  78  has therein a cooling path  79  for allowing a cooling water to flow therethrough, to thereby cool the shield lid  78 , the wave-delay member  76  and the like. Further, the shield lid  78  is grounded. Moreover, the planar antenna member  74  is installed to face the workpiece mount base  44  in the processing vessel  42 .  
         [0045]     In case of a wafer having a diameter of, e.g., 8 inch, the planar antenna member  74  is made of a circular conducting plate, e.g., an aluminum plate or a copper plate with a surface thereof silver-plated, wherein the plate has a diameter ranging from 300 to 400 mm and a thickness ranging from 1 to several mm, e.g., 5 mm. Further, the circular plate has a plurality of microwave radiation holes  80  arranged in a concentric or a spiral shape, wherein each of the microwave radiation holes is made of, e.g., a long slit-shaped groove or a circular-shaped hole.  
         [0046]     An opening  86  is formed at a central top portion of the shield lid  78 . A waveguide  82  is connected to the opening  86  and a microwave generating source for generating a microwave of, e.g., 2.45 GHz, is connected to an end portion of the waveguide  82 . Accordingly, the microwave generated from a microwave generating source  84  can be propagated to the planar antenna member  74  via the waveguide  82 . Further, the frequency of the microwave can be 8.35 GHz, 1.98 GHz, and the like.  
         [0047]     To be specific, the waveguide  82  includes a coaxial waveguide  82 A with a circular cross section and a rectangular waveguide  82 B with a rectangular cross section, wherein the coaxial waveguide  82 A is directly connected and upwardly fixed to the central opening  86  of the shield lid  78  and the rectangular waveguide  82 B is horizontally connected and fixed to a top portion of the coaxial waveguide  82 A via a mode converter  88  for converting a vibration mode of the microwave.  
         [0048]     Furthermore, connected to the antenna member  74  is a member elevating mechanism  85  for relatively varying a vertical distance between the antenna member  74  and the shield lid  78 . Specifically, the coaxial waveguide  82 A has therein a stick-shaped internal conductor  90  extending through a center of the coaxial waveguide  82 A, and a bottom end of the internal conductor  90  is connected and fixed to a central portion of the planar antenna member  74  to thereby hold the planar antenna member  74 . The internal conductor  90  is a part of the member elevating mechanism  85  as a driving shaft. Further, a screw  92  formed at an upper portion of the internal conductor  90  is screw-coupled to a ridge  94 , serving as a screw holder, provided on a ceiling wall of the mode converter  88 . A top end of the screw  92  penetrates through a ceiling wall of the mode converter  88  so that the top end of the screw  92  may be connected to a shaft of a screw driving motor  96  fixed to the mode converter  88  by a holder  98 . Therefore, the screw  92  is rotated by the screw driving motor  96  such that the planar antenna member  74  and the wave-delay member  76  provided thereon can be elevated (moved up and down) as a unit (shown in  FIG. 2 ).  
         [0049]     Meanwhile, a pin hole  100  is formed on a sidewall of the rectangular waveguide  82 B. Installed through the pin hole  100  is a tuning rod  104  connected to an actuator  102  serving as a tuning rod driving device, the tuning rod  104  being insertable (protrusile) into the rectangular waveguide  82 B. Further, the actuator  102  is fixed to the rectangular waveguide  82 B by a holder  106 . The tuning rod  104  is made of, e.g., a metal conductor, lead zirconate titanate (PZT), alumina, ceramic and the like. An insert portion of the tuning rod  104  functions as an impedance while a front end space portion functions as a reactance, so that the impedance can be controlled by varying an insert amount of the tuning rod  104  into the rectangular waveguide  82 B. The tuning rod  104  may be grounded, if necessary.  
         [0050]     Further, installed on the rectangular waveguide  82 B located further upstream from an install position of the tuning rod  104  is a reflection wave detecting section  108  for detecting a state of a reflection wave of the microwave. The reflection wave detecting section  108  has a pair of detecting probes  110  provided inside rectangular waveguide  82 A, the detecting probes  110  being apart from each other by a distance L 1  corresponding to a quarter of a wavelength λ along a propagation direction of the microwave. When a signal detected from the detecting probes  110  are inputted into a detecting body  112 , a power and a phase of the reflection wave can be measured.  
         [0051]     An output of the detecting body  112  is outputted to a matching control section  114  including, e.g., a microcomputer. The matching control section  114  outputs a driving signal to be used for a matching adjustment to each of the screw driving motor  96  and the actuator  102 .  
         [0052]     Hereinafter, a processing method performed by using the plasma processing apparatus described above will be described.  
         [0053]     First of all, a semiconductor wafer W is introduced into the processing vessel  42  by a transfer arm (not shown) via the gate valve  60  and then mounted onto a mounting surface of the workpiece mount base  44  by moving vertically a lifter pin (not shown).  
         [0054]     Further, an inner space of the processing vessel  42  is maintained at a certain processing pressure and provided with, e.g., Ar gas or a deposition gas such as SiH 4  gas, O 2  gas, N 2  gas and the like supplied through the gas supply nozzle  58  with flow rates thereof controlled, respectively. At the same time, a microwave is supplied from the microwave generating source  84  to the planar antenna member  74  sequentially via the rectangular waveguide  82 B, the mode converter  88  and the coaxial waveguide  82 A so that a microwave with a wavelength thereof shortened by the wave-delay member  76  may be introduced into a processing space S, thereby generating a plasma to perform a certain plasma process, e.g., a film forming process by a plasma CVD.  
         [0055]     Herein, the microwave generated from the microwave generating source  84  is propagated as a TE mode within the rectangular waveguide  82 B. The TE mode of the microwave is converted into a TEM mode by the mode converter  88  so that the microwave may be propagated as the TEM mode through the coaxial waveguide  82 A toward the antenna member  74 .  
         [0056]     A reflection wave of the microwave may be generated inside the waveguide  82  due to various factors such as a plasma state or a pressure state in the processing space S. A power or a phase of the reflection wave is detected by the reflection wave detecting section  108 . In order to minimize the reflection wave, the matching control section  114  moves the tuning rod  104  vertically to vary an insert amount thereof or elevates the planar antenna member  74  to vary a distance L 2  between the planar antenna member  74  and the shield lid  78 . That is, the matching control section  114  performs a matching function.  
         [0057]     As illustrated in  FIG. 2 , the insert amount of the tuning rod  104  into the rectangular waveguide  82 B is controlled so that an impedance including an L component thereof and a C component thereof may be modified. Further, the distance L 2  between the planar antenna member  74  and the shield lid  78  provided thereabove is controlled so that the impedance may be modified and, therefore, the impedance in the waveguide  82  may be modified to minimize the reflection wave. The impedance adjustment for minimizing the reflection wave is continuously performed by the matching control section  114  during the plasma process.  
         [0058]     A condition for the impedance adjustment will be described with reference to a Smith chart illustrated in  FIG. 3 . Above all, by adjusting the tuning rod  104  of the rectangular waveguide  82 B, a combined impedance seen from the detecting body  112  moves along a track of a curved line b on the Smith chart and then finally reaches a center O, thereby performing a matching. Therefore, by elevating the planar antenna member  74 , it is desirable to determine the distance L 2  which will most likely make the combined impedance follow a track like a curved line a. Preferably, as illustrated by the curved line a, the combined impedance seen from the detecting body  112  moves along a circle, which shows a real part of a normalized impedance is a constant.  
         [0059]     In this case, a maximum stroke of the distance L 2  on the planar antenna member  74  depends on the wavelength of the microwave and is chosen to be about a half of a shortened wavelength λ 1  due to the wave-delay member  76 , e.g., 60 mm.  
         [0060]     As described above, since the elevating planar antenna member  74  and the vertically moving tuning rod  104  are used to perform the matching adjustment, the large-sized matching circuit  34  (shown in  FIG. 9 ) required in the conventional apparatus becomes unnecessary. Further, since a length of the waveguide itself can be shortened, a size and a weight of a propagation system for the microwave can be greatly reduced.  
         [0061]     Furthermore, due to the scaling-down and the light-weighting of the propagation system for the microwave, the waveguide  82  (including  82 A and  82 B), the mode converter  88  and the microwave generating source  84  can be assembled to be mounted via the shield lid  78  as a unit. As a result, the maintenance and repair works of the processing apparatus can be carried out simply by separating the shield lid  78  from the processing vessel  42 , thereby facilitating a rapid maintenance and repair work.  
         [0062]     Moreover, since the overall length of the waveguide in which a multiple reflection wave may be generated can be totally shortened, a loss of the microwave can be reduced.  
         [0063]     In addition, although only the insert amount of the tuning rod  104  into the rectangular waveguide  82 B can be adjusted in this embodiment, the present invention is not limited thereto. Specifically, the tuning rod  104  may move along a longitudinal direction of the rectangular waveguide  82 B.  FIG. 4  provides a partially enlarged view for a modified example of the tuning rod. The pin hole  100  is chosen to be a long hole having a predetermined length along the longitudinal direction of the rectangular waveguide  82 B. Further, a second actuator  120  may allow the actuator  102  to move along a longitudinal direction of the rectangular waveguide  82 B, wherein the actuator  102  directly moves up and down the tuning rod  104 . Further, the second actuator  120  may be supportively fixed to the rectangular waveguide  82 B by the holder  106 . Furthermore, all the elements described above may be covered by a shield  121  to prevent the microwave from leaking.  
         [0064]     Accordingly, a longitudinal location of the rectangular waveguide  82 B as well as the insert amount of the tuning rod  104  into the rectangular waveguide  82 B can be adjusted, thereby making a matching adjustment be performed properly.  
         [0065]     Although the distance L 2  between the planar antenna member  74  and the shield lid  78  is adjusted by elevating the planar antenna member  74  in this embodiment, the shield lid  78  can be elevated instead of the planar antenna member  74 .  FIG. 5  presents a plasma processing apparatus in accordance with a second preferred embodiment of the present invention. Like reference numerals have been assigned to parts identical or similar to those described in  FIG. 1  to thereby omit detailed explanation thereof.  
         [0066]     As illustrated in  FIG. 5 , in the second preferred embodiment, a planar antenna member  74  is fixed to a supporting frame member  66  provided above a processing vessel  42 , and a top end of an internal conductor  90  installed in a coaxial waveguide  82 A is fixed to a mode converter  88  by a ridge  94 . In addition, a screw driving motor  96  (shown in  FIG. 1 ) is not installed in the second embodiment. Further, a bottom end of the internal conductor  90  is connected to a center of the planar antenna member  74 .  
         [0067]     Further, a bottom end of a shield lid  78  is not fixed on a top end of the supporting member  66  but slidably inserted into the top end of the supporting member  66  to thereby make it moveable in a vertical direction. Furthermore, a plurality of, e.g., three, racks  124  (only two racks are shown in  FIG. 5 ) are installed on a side surface of the shield lid  78  along a circumferential direction thereof, the racks  124  being spaced from each other by an approximately identical interval. Each of the racks  124  engages with one of rotary screws  128  rotated clockwise and counterclockwise by a driving motor  126  fixed to the supporting member  66  or the processing vessel  42 . By rotating the rotary screws  128  clockwise and counterclockwise, the shield lid  78  and a structure thereon can be elevated as a unit. Accordingly, the distance L 2  between the shield lid  78  and the planar antenna member  74  can be arbitrarily controlled.  
         [0068]     The second embodiment can also provide the same functions and effects as the processing apparatus described with reference to  FIG. 1 . Further, since the antenna member  74  is fixed in the second embodiment, the distance between the antenna member  74  and the processing space S is not changed so that it is advantageous in that a location at which a plasma is generated in the processing vessel  42  is not changed.  
         [0069]     In the aforementioned embodiments, even if a tuning rod  104  has been installed and the planar antenna member  74  has been relatively elevated with respect to the shield lid  78  to perform a matching function, a small-sized matching circuit using a printed circuit board can be employed instead of the aforementioned embodiments.  
         [0070]      FIG. 6  illustrates a third preferred embodiment of the plasma processing apparatus in accordance with the present invention.  FIG. 7  shows a matching circuit using the printed circuit board. Further, like reference numerals have been assigned to parts identical or similar to those described in  FIG. 1  and detailed explanation thereof is omitted.  
         [0071]     Only a coaxial waveguide  82 A is used as a waveguide  82 , as illustrated in  FIG. 6 . The coaxial waveguide  82 A is vertically installed at a central portion of a shield lid  78  and a small-sized matching circuit  130 , which is a main characteristic feature of the third embodiment, is installed on an upper end of the coaxial waveguide  82 . Further, the matching circuit  130  is connected to a microwave generating source  84  by a coaxial cable  140 .  
         [0072]     Specifically, the matching circuit  130  has a base formed by a printed circuit board  132 , as illustrated in  FIG. 7 . A plurality of, e.g., six in  FIG. 7 , series connections are connected in parallel on the printed circuit board  132 , each series connection having a phase advance element, i.e., a capacitor, and a switching device. A phase delay element, i.e., a coil  134 , is installed in a middle of the parallel connection described above. The six series connections includes six capacitors C 1  to C 6  and six switching devices SW 1  to SW 6  connected in series, respectively, and the coil  134  is installed between the capacitor C 3  and the capacitor C 4 . Further, one end of a capacitor C 1  is connected to the coaxial cable  140  located above while the other end of a capacitor C 6  is connected to an internal conductor  90  located below.  
         [0073]     Capacitances of the capacitors C 1  to C 6  are different from each other, and different weights are applied thereto. If the symbols C 1  to C 6  are indicated as capacitances thereof, the weights of the capacitances are applied in accordance with an exponential in binary as follows:
 
C 2 =2 1 ×C 1 
 
C 3 =2 2 ×C 1 
 
C 4 =2 3 ×C 1 
 
C 5 =2 4 ×C 1 
 
C 6 =2 5 ×C 1 
 
         [0074]     Further, by appropriately combining and switching the switching devices SW 1  to SW 6 , a combined capacitance within a wide range can be applied thereto. Each of the capacitors C 1  to C 6  can be easily formed by performing a pattern etching on the printed circuit board  132 .  
         [0075]     Further, the switching devices SW 1  to SW 6  can be easily formed by arranging PIN diodes on the printed circuit board  132 , for example. Furthermore, instead of the PIN diodes, mechanical micro relays can be used. Each of the switching devices SW 1  to SW 6  is appropriately switched by an instruction from a matching control section  114 .  
         [0076]     The number of series connections, each having a capacitor and a switching device, is not limited to six. The more series connections there are, the higher may be a resolution of a reactance. Further, an IC chip having an integrated circuit which functions as a reflection wave detecting section  108  or the matching control section  114  can be mounted on the printed circuit board  132 , or a circuit which functions as described above can be built onto the printed circuit board  132 .  
         [0077]     In accordance with the third preferred embodiment, an opening and closing of each of the switching devices SW 1  to SW 6  is appropriately selected by the instruction of the matching control section  114 , so that an impedance of the matching circuit  130  can be appropriately modified and, thus, a reflection wave of the microwave can be minimized.  
         [0078]     The structure described above can be implemented on a printed circuit board (PCB). In the third embodiment, the capacitor, i.e., the phase advance element, and the coil, i.e., the phase delay element, may be formed with an open stub and/or a short stub using microstrip lines, as illustrated in  FIGS. 8A and 8B . In  FIG. 8A , if a length L of a stub  150  is smaller than a quarter of the wavelength, the stub  150  serves as the capacitor (phase advance element) and, if the length L is greater than a quarter of the wavelength and smaller than a half of the wavelength, the stub  150  serves as the inductor (phase delay element).  
         [0079]     Contrary to  FIG. 8A , in  FIG. 8B , if a length L of a stub  152  is smaller than a quarter of the wavelength, the stub  152  serves as the inductor (phase delay element) and, if the length L is greater than a quarter of the wavelength and smaller than a half of the wavelength, the stub  152  serves as the capacitor (phase advance element).  
         [0080]     By variously varying the length L of the stub, various phase advance element and phase delay element can be manufactured on the PCB.  
         [0081]     Therefore, a large-sized matching circuit in the conventional processing apparatus is not needed and, further, a size and a weight of the processing apparatus can be reduced, thereby obtaining the same functions and effects as described in the aforementioned embodiments.  
         [0082]     Although the film forming process on the semiconductor wafer was exemplarily described in the present embodiment, the present invention is not limited thereto but can be applied to other plasma processes such as a plasma etching process, a plasma ashing process and the like.  
         [0083]     As described above, the plasma processing apparatus in accordance with the present invention has the functions and effects as will be described below.  
         [0084]     In accordance with the plasma processing apparatus of the present invention, both the planar antenna member which is relatively moved up and down and the tuning rod whose insert amount into the waveguide may be controllable are used to perform a matching function for preventing the reflection wave of the microwave from being generated. Thus, the structure of the propagation system of the microwave can be greatly reduced and, accordingly, the propagation system of the microwave, which includes the microwave generating source, can be mounted on the shield lid as a unit. As a result, the maintenance and the repair of the plasma processing apparatus can be carried out simply by separating the shield lid from the processing vessel without separating the waveguide and the like, so that the maintenance and the repair can be performed quickly and easily.  
         [0085]     Further, since the length of the waveguide for propagating the microwave therethrough can be shortened, it is possible to suppress the generation of the reflection wave and/or the power loss.  
         [0086]     Furthermore, in accordance with the plasma processing apparatus of the present invention, the printed circuit board may be used to scale down the matching circuit. Thus, the structure of the propagation system of the microwave can be greatly reduced and, accordingly, the propagation system of the microwave, which includes the microwave generating source, can be mounted on the shield lid as a unit.  
         [0087]     As a result, the maintenance and the repair of the plasma processing apparatus can be carried out simply by separating the shield lid from the processing vessel without separating the waveguide and the like, so that the maintenance and the repair work can be performed quickly and easily.  
         [0088]     Further, since the length of the waveguide for propagation therethrough the microwave can be shortened, it is possible to suppress the generation of the reflection wave or the power loss.  
         [0089]     While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.