Patent Publication Number: US-2012031560-A1

Title: Plasma processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Japanese Patent Application No. 2010-175401 filed on Aug. 4, 2010 and U.S. Provisional Application Ser. No. 61/375,562 filed on Aug. 20, 2010, the entire disclosures of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure relates to an inductively coupled plasma processing apparatus for performing a plasma process on a substrate. 
     BACKGROUND OF THE INVENTION 
     In a manufacturing process of a semiconductor device or a flat panel display (FPD) such as a liquid crystal display (LCD), there is known a plasma processing apparatus for performing a plasma process on various kinds of substrates such as a glass substrate. The plasma processing apparatus can be classified into a capacitively coupled plasma processing apparatus and an inductively coupled plasma processing apparatus according to a plasma generation method. 
     In an inductively coupled plasma processing apparatus (hereinafter, simply referred to as an “ICP processing apparatus”), a high frequency power is applied to a high frequency antenna (hereinafter, referred to as a “RF antenna”) via a dielectric member, such as quartz, disposed at a part of the processing chamber. The high frequency antenna has a vortex shape, a coil shape or a spiral shape, and is provided at an outside of a processing chamber (chamber). An induced magnetic field is formed around the RF antenna to which the high frequency power is applied, and plasma of a processing gas is generated by the induced electric field formed within the chamber by the induced magnetic field. A plasma process is performed on the substrate by the generated plasma. 
     In such an ICP processing apparatus, since the plasma is mainly generated by the induced electric field, high-density plasma can be obtained. Due to this advantage, the ICP processing apparatus has been appropriately used in an etching process or a film forming process in manufacturing a FPD or the like. 
     Further, recently, there has been developed a technique for effectively preventing foreign substances generated during the plasma process from adhering to the dielectric member disposed within the chamber of the ICP processing apparatus (See, for example, Patent Document 1).
     Patent Document 1: Japanese Patent Laid-open Publication No. 2003-209098   

     In the ICP processing apparatus, however, even if a multiple number of RF antennas are provided and a high frequency power for plasma generation (hereinafter, referred to as an “excitation RF H ”) applied to the RF antennas is controlled, it may be difficult to generate plasma so as to be distributed in one-to-one correspondence to the RF antennas. That is, it may be difficult to control a plasma distribution within the chamber as desired. 
       FIG. 16  provides a cross sectional view of a plasma processing apparatus in order to describe a state in which plasma is generated at positions different from those corresponding to high frequency antennas. 
     As depicted in  FIG. 16 , a dielectric member (hereinafter, referred to as a “dielectric window”)  202  is provided in a ceiling portion of a chamber  201  of a plasma processing apparatus  200 . Circular ring-shaped RF antennas  203   a  and  203   b  are concentrically disposed on or above the dielectric window  202 , i.e., in a space adjacent to a processing space S of the chamber  201  via the dielectric window  202 . One ends of the circular ring-shaped RF antennas  203   a  and  203   b  are connected with high frequency powers  204   a  and  204   b  for plasma generation via matching units, respectively, and other ends thereof are grounded. 
     In this plasma processing apparatus  200 , when an excitation RF H  is applied to the RF antennas  203   a  and  203   b , double plasma individually corresponding to the two concentric circular ring-shaped RF antennas  203   a  and  203   b  may not be generated, but single circular ring-shaped plasma  205  corresponding to an intermediate position between the two circular ring-shaped RF antennas  203   a  and  203   b  is generated. 
     The reason for this phenomenon is deemed to be as follows. If the excitation RF H  is applied to the circular ring-shaped RF antennas  203   a  and  203   b , a high frequency current flows in the RF antennas  203   a  and  203   b , and an induced magnetic field  206  is formed around the respective RF antennas  203   a  and  203   b . As a result, the single circular ring-shaped plasma  205  is formed at a position corresponding to a space where a combined induced magnetic field is strong. 
     That is, in the conventional plasma processing apparatus, it may be difficult to generate plasma in one-to-one correspondence to the RF antennas  203   a  and  203   b . Thus, it may be difficult to control a plasma distribution within the chamber. 
     BRIEF SUMMARY OF THE INVENTION 
     In view of the foregoing, the present disclosure provides a plasma processing apparatus capable of generating plasma in one-to-one correspondence to high frequency antennas according to a high frequency power, and also capable of controlling a plasma distribution within a processing chamber. 
     To solve the above-mentioned problems, in accordance with one aspect of the present disclosure, there is provided a plasma processing apparatus including an evacuable processing chamber for performing therein a plasma process on a substrate; a substrate mounting table for mounting thereon the substrate within the processing chamber; a dielectric window provided to face the substrate mounting table via a processing space; a multiple number of high frequency antennas disposed in a space adjacent to the processing space with the dielectric window positioned therebetween; a gas supply unit for supplying a processing gas into the processing space; a high frequency power supply for applying a high frequency power to the multiple number of high frequency antennas to thereby generate plasma of the processing gas by an inductive coupling; and a combination preventing member for preventing induced magnetic fields corresponding to the multiple number of high frequency antennas from being combined with each other. 
     Further, the combination preventing member may be a protrusion made of a dielectric material and provided on a surface of the dielectric window facing the processing space, and the combination preventing member may be located at a position corresponding to an inter-position of the multiple number of high frequency antennas. 
     Furthermore, a thickness of a portion of the dielectric window corresponding to the multiple number of high frequency antennas may be smaller than that of the other portion of the dielectric window. 
     A protrusion made of a material having a magnetic permeability different from that of the dielectric window may be provided at an inter-position of the multiple number of high frequency antennas. 
     Moreover, the protrusion made of a material having a magnetic permeability different from that of the dielectric window may be provided on a surface of the dielectric window facing the processing space or on a surface of the dielectric window opposite to the processing space. 
     A part of the protrusion made of a material having a magnetic permeability different from that of the dielectric window may be inserted and buried in the dielectric window. 
     Further, the multiple number of high frequency antennas may be spaced apart from each other at a distance enough for preventing the induced magnetic fields corresponding to the multiple number of high frequency antennas from being combined with each other. 
     The dielectric window may be divided so as to correspond to the multiple number of high frequency antennas, and a conductor, which is grounded, may be disposed between the divided dielectric windows. 
     In accordance with the present disclosure, it is possible to generate plasma in one-to-one correspondence to the high frequency antennas according to a high frequency power, and it is also possible to control a plasma distribution within the processing chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Non-limiting and non-exhaustive embodiments will be described in conjunction with the accompanying drawings. Understanding that these drawings depict only several embodiments in accordance with the disclosure and are, therefore, not to be intended to limit its scope, the disclosure will be described with specificity and detail through use of the accompanying drawings, in which: 
         FIG. 1  is a cross sectional view schematically showing a configuration of a plasma processing apparatus in accordance with a first embodiment of the present disclosure; 
         FIG. 2  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a second embodiment of the present disclosure; 
         FIG. 3  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a third embodiment of the present disclosure; 
         FIG. 4  is a cross sectional view schematically illustrating a major configuration of a modification example of the third embodiment; 
         FIG. 5  is a cross sectional view schematically illustrating a major configuration of another modification example of the third embodiment; 
         FIG. 6  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a fourth embodiment of the present disclosure; 
         FIG. 7  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a fifth embodiment of the present disclosure; 
         FIG. 8  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a sixth embodiment of the present disclosure; 
         FIG. 9  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a seventh embodiment of the present disclosure; 
         FIG. 10  is a cross sectional view schematically illustrating a major configuration of a modification example of the seventh embodiment; 
         FIG. 11  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with an eighth embodiment of the present disclosure; 
         FIG. 12  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a ninth embodiment of the present disclosure; 
         FIG. 13  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a tenth embodiment of the present disclosure; 
         FIG. 14  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with an eleventh embodiment of the present disclosure; 
         FIG. 15  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a twelfth embodiment of the present disclosure; and 
         FIG. 16  provides a cross sectional view of a plasma processing apparatus in order to describe a state in which plasma is generated at positions different from those corresponding to high frequency antennas. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Hereinafter, non-limiting embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a cross sectional view schematically illustrating a configuration of a plasma processing apparatus in accordance with a first embodiment of the present disclosure. This plasma processing apparatus performs a plasma process such as etching process or film forming process on, e.g., a glass substrate for manufacturing a liquid crystal display (LCD). 
     As depicted in  FIG. 1 , a plasma processing apparatus may include a processing chamber  11  for accommodating therein a glass substrate to be processed (hereinafter, simply referred to as a “substrate”) G. A cylindrical mounting table (susceptor)  12  for mounting thereon the substrate G is provided in a lower part of the chamber  11 . The susceptor  12  may mainly include a base member  13  made of, e.g., aluminum of which surface is alumite-treated, and the base member  13  is supported on a bottom of the chamber  11  with an insulating member  14  provided therebetween. A top surface of the base member  13  is a substrate mounting surface on which the substrate G is mounted, and a focus ring  15  is provided so as to surround the substrate mounting surface. 
     An electrostatic chuck (ESC)  20  having an electrostatic electrode plate  16  therein may be provided on the substrate mounting surface of the base member  13 . The electrostatic electrode plate  16  may be connected with a DC power supply  17 . If a positive DC voltage is applied to the electrostatic electrode plate  16 , a negative potential may be generated on a surface (hereinafter, referred to as a “rear surface”) of the substrate G facing the electrostatic electrode plate  16 . Accordingly, a potential difference may be generated between the electrostatic electrode plate  16  and the rear surface of the substrate G. The substrate G is attracted to and held on the substrate mounting surface by a Coulomb force or a Johnsen-Rahbek force generated due to the potential difference. 
     A circular ring-shaped coolant cavity  18  is formed in the base member  13  of the susceptor  12  on a circumference. A coolant of a low temperature, such as cooling water or Galden (Registered Trademark) is supplied and circulated into the coolant cavity  18  through a coolant line  19  from a chiller unit (not shown). The susceptor  12  cooled by the coolant may cool the substrate G and the focus ring  15  via the electrostatic chuck  20 . 
     A multiple number of heat transfer gas supply holes are formed in the base member  13  and the electrostatic chuck  20 . Each heat transfer gas supply hole  21  is connected with a non-illustrated heat transfer gas supply unit, and a heat transfer gas such as a helium (He) gas is supplied into a gap between the electrostatic chuck  20  and the rear surface of the substrate G. The He gas supplied into the gap between the electrostatic chuck  20  and the rear surface of the substrate G transfers heat of the substrate G to the susceptor  12 , effectively. 
     A high frequency power supply  24  for supplying a high frequency power for biasing (hereinafter, referred to as a “bias RF L ”) may be connected to the base member  13  of the susceptor  12  via a matching unit  23  and a power supply rod  22 . The susceptor  12  serves as a lower electrode and the matching unit  23  reduces reflection of a high frequency power from the susceptor  12 , thus maximizing the efficiency of applying the high frequency power to the susceptor  12 . A bias RF L  equal to or less than about 40 MHz, e.g., about 13.56 MHz, may be applied to the susceptor  12  from the high frequency power supply  24 , so that plasma generated in the processing space S is attracted toward the substrate G. 
     In the plasma processing apparatus  10 , a side exhaust path  26  is formed between an inner sidewall of the chamber  11  and a side surface of the susceptor  12 . The side exhaust path  26  is connected with a gas exhaust unit  28  via an exhaust line  27 . The gas exhaust unit  28  may include a TMP (Turbo Molecular Pump) and a DP (Dry Pump) (both are not shown), and evacuates and depressurizes the inside of the chamber  11 . To elaborate, the DP may depressurize the inside of the chamber  11  from an atmospheric pressure to an intermediate vacuum state (e.g., about 1.3×10 Pa (0.1 Torr) or less), and the TMP may further depressurize the inside of the chamber  11  to a high vacuum state (e.g., about 1.3×10 −5  Pa (1.0×10 −5  Torr) or less) lower than the intermediate vacuum state in cooperation with the DP. Further, an internal pressure of the chamber  11  may be controlled by an APC value (not shown). 
     A dielectric window  30  is provided at a ceiling portion of the chamber  11  so as to face the susceptor  12  via the processing space S. The dielectric window  30  is made of, e.g., a quartz plate and is airtightly sealed. Further, the dielectric window  30  transmits magnetic force lines. In an upper space  29  above the dielectric window  30 , circular ring-shaped RF antennas  31   a  and  31   b  may be concentrically arranged and may be coaxially positioned with respect to, e.g., the susceptor  12 . The circular ring-shaped RF antennas  31   a  and  31   b  are fixed on a surface (hereinafter, referred to as a “top surface”) of the dielectric window  30  opposite to the processing space S by a fixing member (not shown) made of, e.g., an insulator. 
     One ends of the RF antennas  31   a  and  31   b  are electrically connected with high frequency power supplies  33   a  and  33   b  for plasma generation via matching units  32   a  and  32   b , respectively. Other ends of the RF antennas  31   a  and  31   b  are grounded. The high frequency power supplies  33   a  and  33   b  output, by a high frequency discharge, a high frequency power RF H  having a frequency of, e.g., about 13.56 MHz suitable for plasma generation, and apply the outputted high frequency power RF H  to the RF antennas  31   a  and  31   b . The matching units  32   a  and  32   b  have the same function as that of the matching unit  23 . 
     An annular manifold  36  may be formed in a sidewall of the chamber  11  below the dielectric window  30  along an inner periphery of the chamber  11 . The annular manifold  36  is connected with a processing gas supply source  37  via a gas flow path. The manifold  36  is provided with, by way of example, a multiple number of gas discharge openings  36   a  arranged at a regular distance. A processing gas introduced into the manifold  36  from the processing gas supply source  37  is supplied into the chamber  11  through the gas discharge openings  36   a.    
     The plasma processing apparatus  10  may further include a combination preventing member for preventing induced magnetic fields formed around the RF antennas  31   a  and  31   b  from being combined with each other. Here, the high frequency powers are applied to the RF antennas  31   a  and  31   b  from the high frequency powers supplies  33   a  and  33   b.    
     That is, protrusions  34  made of a dielectric material are provided on a surface (hereinafter, referred to as a “bottom surface”) of the dielectric window  30  facing the processing space S. To elaborate, each protrusion  34  is located at a position corresponding to an inter-position of the circular ring-shaped RF antennas  31   a  and  31   b . Here, the term “inter-position of RF antennas” is a wide term including not only a gap between independent RF antennas but also a gap in a vortex or a spiral of a vortex-shaped or a spiral-shaped RF antenna. Further, the term of “inter-position of RF antennas” also includes a central area of the circular ring-shaped RF antenna. Hereinafter, the term “inter-position of RF antenna” has the above-mentioned meaning over the whole disclosure. By way of example, yttria, alumina, or the like can be used as the dielectric material for forming the protrusion  34  and, desirably, glass may be used appropriately. Since the protrusion  34  physically occupies a position where a combined magnetic field may be formed, plasma caused by the combined magnetic field cannot exist. As a result, plasma may be generated at a position corresponding to the respective RF antennas  31   a  and  31   b.    
     A substrate loading/unloading port  38  is formed in the sidewall of the chamber  11 . The substrate loading/unloading port  38  can be opened and closed by a gate valve  39 . The substrate G to be processed is loaded into and unloaded from the chamber  11  via the substrate loading/unloading port  38 . 
     In the plasma processing apparatus  10  having the above-described configuration, a processing gas is supplied into the processing space S of the chamber  11  from the processing gas supply source  37  via the manifold  36  and the gas discharge openings  36   a . Further, the excitation RF H  is applied to the RF antennas  31   a  and  31   b  from the high frequency power supplies  33   a  and  33   b  via the matching units  32   a  and  32   b , respectively, so that high frequency current flows in the RF antennas  31   a  and  31   b . As the high frequency current flows, an induced magnetic field is formed around the RF antennas  31   a  and  31   b . Further, an induced electric field is formed in the processing space S due to the induced magnetic field. Electrons accelerated by the induced electric field collide with molecules or atoms of the processing gas. Thus, the processing gas is ionized and excited into plasma by the induced electric field. 
     Ions in the generated plasma are attracted toward the substrate G by the bias RF L  applied to the susceptor  12  from the high frequency power supply  24  via the matching unit  23  and the power supply rod  22 , so that a plasma process is performed on the substrate G. 
     An operation of each component of the plasma processing apparatus  10  may be controlled by a CPU of a controller (not shown) included in the plasma processing apparatus  10  according to a program for the plasma process. 
     In accordance with the first embodiment as described above, the protrusions  34  made of glass and having circular ring shapes or circular shapes may be provided on the bottom surface of the dielectric window  30  at positions corresponding to the inter-position of the RF antennas  31   a  and  31   b . Specifically, the protrusions  34  may be provided at the positions corresponding to the gap between the RF antennas  31   a  and  31   b , and the central space of the circular ring-shaped RF antenna  31   a . Accordingly, plasma cannot exist at positions where a combined magnetic field may be formed by the induced magnetic field generated around the RF antenna  31   a  and the induced magnetic field generated around the RF antenna  31   b . As a consequence, the induced magnetic fields corresponding to the RF antenna  31   a  and the RF antenna  31   b , respectively can be maintained, and the induced electric field may be generated by the respective induced magnetic fields. Accordingly, due to the induced electric field, the plasma corresponding to the respective RF antennas  31   a  and  31   b  may be generated according to the applied high frequency power RF H . 
     In accordance with the first embodiment, by disposing a RF antenna at a position within the chamber  11  corresponding to a position in which plasma needs to be generated and by adjusting the high frequency power RF H  applied to this RF antenna, it is possible to control a plasma distribution within the chamber  11 . 
     In accordance with the first embodiment, the protrusions  34  made of the dielectric material may be made of the same material as a material of the dielectric window  30  as a single body therewith, or the protrusions  34  may be made of a material different from the material of the dielectric window  30  as a separate body therefrom. 
     In accordance with the first embodiment, by way of example, a manifold may be formed in the circular ring-shaped or circular protrusion  34  made of the dielectric material. In such a case, the protrusion  34  may serve as a gas introduction member. 
       FIG. 2  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a second embodiment of the present disclosure. 
     Recently, as a size of the substrate G to be processed increases, the chamber  11  is also getting scaled up. Further, in order to maintain a vacuum level in the interior of the chamber  11  having such a big size, a thickness of the dielectric window  30  is also getting larger. If the thickness of the dielectric window  30  becomes larger, a distance between RF antennas  31   a  and  31   b  and a processing space S within the chamber  11  is increased, so that a combined magnetic field may be easily formed at an intermediate position between the adjacent RF antennas. As a result, it may be difficult to form plasma in one-to-one correspondence to the respective RF antennas. The second embodiment is designed to solve such a problem. In accordance with the second embodiment, a thickness of a portion of the dielectric window  30  corresponding to the respective RF antennas  31   a  and  31   b  is set to be smaller than that of the other portion of the dielectric window  30 . With this configuration, it is possible to generate plasma  42  in one-to-one correspondence to the respective RF antennas  31   a  and  31   b  within the chamber  11 . 
     To elaborate, as shown in  FIG. 2 , a plasma processing apparatus  40  is different from the plasma processing apparatus  10  of  FIG. 1  in the following configuration. That is, instead of forming the circular ring-shaped or circular protrusions  34  made of the dielectric material at the positions on the bottom surface of the dielectric window  30  corresponding to the inter-position of the RF antennas  31   a  and  31   b , circular ring-shaped recesses  41  are formed at positions on the bottom surface of the dielectric window  30  corresponding to the respective RF antennas  31   a  and  31   b . Therefore, the thickness of portions of the dielectric window  30  corresponding to the RF antennas  31   a  and  31   b  are set to be smaller than that of the other portion of the dielectric window  30 . 
     In accordance with the second embodiment, since the circular ring-shaped recesses  41  are formed at the positions on the bottom surface of the dielectric window  30  corresponding to the RF antennas  31   a  and  31   b  and the thickness of those portions is smaller than that of the other portion of the dielectric window  30 , an induced magnetic field stronger than a combined magnetic field is formed directly under the respective RF antennas  31   a  and  31   b . Accordingly, it is possible to generate the plasma  42  within the chamber  11  in one-to-one correspondence to the respective RF antennas  31   a  and  31   b.    
     In accordance with the second embodiment, the thickness of the dielectric window  30  may be in the range of, e.g., about 20 mm to about 50 mm. Further, the thickness of the portions of the dielectric window  30  where the recesses  41  are formed may be in the range of, e.g., about 10 mm to about 20 mm. 
     In the second embodiment, the circular ring-shaped recesses  41  are formed along the entire peripheries of the dielectric window  30  so as to correspond to the RF antennas  31   a  and  31   b . However, it may be also possible to form the recesses  41  on a part of the entire peripheries of the dielectric window  30  in consideration of the strength of the dielectric window  30 . 
       FIG. 3  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a third embodiment of the present disclosure. 
     As depicted in  FIG. 3 , a plasma processing apparatus  50  is different from the plasma processing apparatus  10  of  FIG. 1  in the following configuration. That is, instead of forming the circular ring-shaped or circular protrusions  34  made of the dielectric material at the positions on the bottom surface of the dielectric window  30  corresponding to the inter-position of the RF antennas  31   a  and  31   b , circular ring-shaped or circular protrusions  51   a  made of a material having a magnetic permeability different from that of a dielectric window  30  are formed on a top surface of the dielectric window  30  at positions corresponding to the inter-position of the RF antennas  31   a  and  31   b.    
     In accordance with the third embodiment, since the circular ring-shaped or circular protrusions  51   a  made of the material having the magnetic permeability different from that of the dielectric window  30  are provided at the inter-position of the RF antennas  31   a  and  31   b , magnetic force lines in induced magnetic fields formed around the respective RF antennas  31   a  and  31   b  may be varied due to the protrusions  51   a , so that a generated plasma may also vary. Therefore, a combined magnetic field may not be formed. 
     Accordingly, induced electric fields corresponding to the respective RF antennas  31   a  and  31   b  may be formed within the chamber  11 . Then, circular ring-shaped plasma  52  corresponding to the respective RF antennas  31   a  and  31   b  may be generated by the induced electric fields. 
     In accordance with the third embodiment, the plasma can be generated at positions corresponding to the respective RF antennas  31   a  and  31   b , and intensity of the plasma  52  can be controlled by the applied excitation RF H . Thus, it is much easier to control the plasma within the chamber  11 . 
     In accordance with the third embodiment, ferrite, permalloy or the like may be used as the material having the magnetic permeability different from that of the dielectric window  30 . The protrusions  51   a  may be made of, e.g., ferrite. 
       FIG. 4  is a cross sectional view schematically illustrating a major configuration of a modification example of the third embodiment. 
     As shown in  FIG. 4 , a plasma processing apparatus  50  is different from the plasma processing apparatus of  FIG. 3  in the following configuration. That is, a cross sectional area of a protrusion  51   b  made of a material having a magnetic permeability different from that of the dielectric window  30  is slightly larger than that of the protrusion  51   a . Further, a part of the protrusion  51   b  is inserted and buried in, e.g., a spot facing portion formed in a top surface of the dielectric window  30 . 
     In accordance with the modification example of the third embodiment, the same effect as obtained in the third embodiment can also be achieved. 
     Furthermore, in accordance with the modification example of the third embodiment, since the cross sectional area of the protrusion  51   b  having a circular ring shape is slightly larger than that of the protrusion  51   a  of the third embodiment, the effect of preventing the combined magnetic field from being formed can be further enhanced. Accordingly, plasma  52  can be generated at positions corresponding to the respective RF antennas  31   a  and  31   b , accurately. Further, since a part of the protrusion  51   b  is insertion-fitted and buried in the dielectric window  30 , it is possible to exactly determine and fix the position of the protrusion  51   b.    
       FIG. 5  is a cross sectional view schematically illustrating a major configuration of another modification example of the third embodiment. 
     As depicted in  FIG. 5 , a plasma processing apparatus  50  is different from the plasma processing apparatus of Fig. in the following configuration. That is, a cross sectional area of a circular ring-shaped protrusion  51   c  is slightly larger than the cross sectional area of the protrusion  51   a  of the third embodiment. Further, the protrusion  51   c  is provided on a bottom surface of the dielectric window  30 . 
     In accordance with this another modification example, the same effect as obtained in the third embodiment can still be achieved. 
     Moreover, in accordance with this another modification example of the third embodiment, since the cross sectional area of the circular ring-shaped protrusion  51   c  is slightly larger than that of the protrusion  51   a  of the third embodiment, the effect of preventing a combined magnetic field from being formed can be further enhanced. Accordingly, plasma  52  can be generated at positions corresponding to the respective RF antennas  31   a  and  31   b , accurately. 
     Further, in accordance with this another modification example of the third embodiment, since the protrusion  51   c  is exposed to the plasma generated within the chamber  11 , it may be desirable to coat the protrusion  51   c  with, e.g., SiO 2  or yttria. In this way, a lifetime of the protrusion  51   c  can be extended. 
       FIG. 6  is across sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a fourth embodiment of the present disclosure. 
     As shown in  FIG. 6 , a plasma processing apparatus  60  is different from the plasma processing apparatus  10  of Fig. in the following configuration. That is, instead of forming the protrusions  34  made of the dielectric material and provided at the positions on the bottom surface of the dielectric window  30  corresponding to the inter-position of the RF antennas  31   a  and  31   b , a diameter of the circular ring-shaped RF antenna  31   b  is set to be very larger than that of the circular ring-shaped RF antenna  31   a , and the RF antenna  31   b  is positioned within the chamber  11 . To elaborate, the RF antenna  31   b  having a diameter larger than the substrate G is positioned outside the dielectric window  30  within the chamber  11 . 
     In accordance with the fourth embodiment, since a gap between the RF antennas  31   a  and  31   b  is large, eddy currents caused by induced magnetic fields generated around the RF antennas  31   a  and  31   b  do not overlap with each other, so that a combined eddy current may not be generated. Accordingly, induced electric fields and plasma  62  in one-to-one correspondence to the respective RF antennas  31   a  and  31   b  may be generated. 
     In accordance with the fourth embodiment, it may be desirable to coat the RF antenna  31   b  positioned within the chamber  11  with a dielectric material such as SiO 2  or yttria. In this way, the RF antenna  31   b  may not be directly exposed to the plasma, so that a lifetime of the RF antenna  31   b  can be extended. 
       FIG. 7  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a fifth embodiment of the present disclosure. 
     As illustrated in  FIG. 7 , a plasma processing apparatus  70  is different from the plasma processing apparatus  10  of  FIG. 1  in the following configuration. That is, instead of forming the protrusions  34  made of the dielectric material and provided at the positions on the bottom surface of the dielectric window  30  corresponding to the inter-position of the RF antennas  31   a  and  31   b , the dielectric window  30  is divided into two parts corresponding to RF antennas  31   a  and  31   b , respectively. Further, a metal serving as a conductor, which is grounded, is disposed between the divided dielectric windows  30 . The metal  71  may be, but not limited to, aluminum. Desirably, a surface of the aluminum in contact with the plasma may be coated with SiO 2  or yttria. 
     The circular ring-shaped RF antenna  31   a  is disposed on a dielectric window  30   a  in a central portion of the chamber  11 , whereas the circular ring-shaped RF antenna  31   b  is disposed on a dielectric window  30   b  in an inner peripheral portion of the chamber  11 . 
     In accordance with the fifth embodiment, the dielectric window  30  is divided into the dielectric window  30   a  positioned in the central portion of the chamber  11  and the dielectric window  30   b  positioned in the inner peripheral portion of the chamber  11 . The metal  71 , which is grounded, is disposed between the dielectric windows  30   a  and  30   b . Accordingly, eddy current in induced magnetic fields respectively formed around the RF antennas  31   a  on the dielectric window  30   a  and the RF antenna  31   b  on the dielectric window  30  flows to the ground through the metal  71 . Thus, the eddy currents may not be combined and plasma  72  corresponding to the respective RF antennas  31   a  and  31   b  can be generated. 
     In the fifth embodiment, it may be possible to provide a processing gas introduction member in the metal  71  that is disposed between the divided dielectric windows. In such a case, the metal  71  may serve as a shower head. 
       FIG. 8  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a sixth embodiment of the present disclosure. 
     As depicted in  FIG. 8 , a plasma processing apparatus includes both an inventive feature of the fifth embodiment and an inventive feature of the second embodiment. That is, a dielectric window  30  is divided into dielectric windows  30   a  and  30   b  corresponding to RF antennas  31   a  and  31   b , respectively. A metal  81 , which is grounded, is disposed between the dielectric windows  30   a  and  30   b . Further, circular ring-shaped recesses  82  are formed in bottom surfaces of the dielectric windows  30   a  and  30   b , so that the thickness of portions of the dielectric windows  30   a  and  30   b  where the recesses  82  are formed is set to be smaller than that of the other portions of the dielectric windows  30   a  and  30   b.    
     In accordance with the sixth embodiment, the dielectric window  30  is divided into the dielectric windows  30   a  and  30   b  corresponding to the RF antennas  31   a  and  31   b , respectively. Further, the metal  81 , which is grounded, is disposed between the dielectric windows  30   a  and  30   b . The circular ring-shaped recesses  82  are formed on the bottom surfaces of the dielectric windows  30   a  and  30   b  corresponding to the respective RF antennas  31   a  and  31   b . Moreover, the thickness of the portions of the dielectric windows  30   a  and  30   b  where the recesses  82  are formed is set to be smaller than that of the other portions of the dielectric windows  30   a  and  30   b . Therefore, eddy current may be suppressed by the metal  81  grounded and the plasma may be generated in the chamber directly under the RF antennas by the induced magnetic fields stronger than the combined magnetic field by thinning the dielectric window. Due to the synergy effect of the above, the plasma  83  can be generated at positions corresponding to the respective RF antennas  31   a  and  31   b  within the chamber  11 . Furthermore, since it is possible to generate the plasma  83  at desired positions within the chamber  11  according to the positions of the RF antennas  31   a  and  31   b , it is much easier to control the plasma within the chamber  11 . 
       FIG. 9  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a seventh embodiment of the present disclosure. 
     As shown in  FIG. 9 , a plasma processing apparatus  90  includes both the inventive feature of the fifth embodiment and the inventive feature of the first embodiment. That is, the dielectric window  30  is divided into dielectric windows  30   a  and  30   b  corresponding to RF antennas  31   a  and  31   b , respectively. A metal  91 , which is grounded, is disposed between the dielectric windows  30   a  and  30   b . Further, a RF antenna  31   c  having a diameter larger than the RF antenna  31   a  is provided on the dielectric window  30   a . Furthermore, protrusions  92  made of a dielectric material are provided on a bottom surface of the dielectric window  30   a  so as to correspond to the inter-position of the RF antennas  31   a  and  31   c.    
     In accordance with the seventh embodiment, the dielectric window  30  is divided into the dielectric windows  30   a  and  30   b  corresponding to the RF antennas  31   a  and  31   b , respectively. The metal  91 , which is grounded, is disposed between the dielectric windows  30   a  and  30   b . Further, the RF antenna  31   c  having the larger diameter than the RF antenna  31   a  is provided on the dielectric window  30   a . Furthermore, the protrusions  92  made of, e.g., glass are provided on the bottom surface of the dielectric window  30   a  so as to correspond to the inter-position of the RF antennas  31   a  and  31   c . Therefore, eddy current may be suppressed by the metal  81  grounded and plasma may be prevented from existing at a position where a combined magnetic field may be formed. Accordingly, due to the synergy effect of the above, it is possible to generate plasma  93  corresponding to the respective RF antennas  31   a  to  31   c  within the chamber  11 . In addition, since it is possible to generate the plasma at desired positions within the chamber  11  so as to correspond to the respective RF antennas  31   a  to  31   c , it is much easier to control the plasma within the chamber  11 . 
       FIG. 10  is a cross sectional view schematically illustrating a major configuration of a modification example of the seventh embodiment. 
     As illustrated in  FIG. 10 , a plasma processing apparatus  90  is different from the plasma processing apparatus of  FIG. 9  in the following configuration. That is, instead of forming the RF antenna  31   c  on the outer periphery portion of the RF antenna  31   a  on the dielectric window  30   a , the RF antenna  31   c  having a diameter smaller than the RF antenna  31   b  may be provided on the dielectric window  30   b  positioned in the inner periphery portion of the chamber  11 . Further, a circular ring-shaped protrusion  94  made of glass is provided on a bottom surface of the dielectric window  30   b  so as correspond to the inter-position of the RF antennas  31   b  and  31   c.    
     In this modification example, the same effect as obtained in the seventh embodiment can also be achieved. 
       FIG. 11  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with an eighth embodiment of the present disclosure. 
     As depicted in  FIG. 11 , a plasma processing apparatus  100  includes both the inventive feature of the fifth embodiment and the inventive feature of the third embodiment. That is, the dielectric window  30  is divided into the dielectric window  30   a  in the central portion of the chamber and the dielectric window  30   b  in the inner peripheral portion of the chamber  11 . A metal  101 , which is grounded, is disposed between the dielectric windows  30   a  and  30   b . Further, the RF antenna  31   c  having a diameter larger than the RF antenna  31   a  is provided on the dielectric window  30   a . Furthermore, circular ring-shaped or circular protrusions  102  having a magnetic permeability different from that of the dielectric window  30   a  are provided on a top surface of the dielectric window  30   a  so as to correspond to the inter-position of the RF antennas  31   a  and  31   c.    
     In accordance with the eighth embodiment, the dielectric window  30  is divided into the dielectric windows  30   a  and  30   b  so as to correspond to the RF antennas  31   a  and  31   b , respectively. The metal  101 , which is grounded, is disposed between the dielectric windows  30   a  and  30   b . Further, the RF antenna  31   c  having the larger diameter than the RF antenna  31   a  is provided on the dielectric window  30   a . Furthermore, the circular ring-shaped or circular protrusions  102  having the magnetic permeability different from that of the RF antenna  31   a  are provided on the top surface of the dielectric window  30   a  so as to correspond to the inter-position of the RF antennas  31   a  and  31   c . Therefore, eddy current may be suppressed by the metal  101  grounded and magnetic force lines may be cut by the protrusions  102  having the magnetic permeability different from that of the dielectric window  30   a . Accordingly, it is possible to generate plasma  103  corresponding to the respective RF antennas  31   a  to  31   c  within the chamber  11 . In addition, since it is possible to generate the plasma at desired positions within the chamber  11  so as to correspond to the respective RF antennas  31   a  to  31   c , it is much easier to control the plasma within the chamber  11 . 
       FIG. 12  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a ninth embodiment of the present disclosure. 
     As shown in  FIG. 12 , a plasma processing apparatus  110  includes both the inventive feature of the third embodiment and the inventive feature of the second embodiment. That is, circular ring-shaped or circular protrusions  111  made of a material having a magnetic permeability different from that of a dielectric window  30  are provided at the inter-position of the RF antennas  31   a  and  31   b . Further, recesses  112  are formed in a bottom surface of the dielectric window  30  so as to correspond to the RF antennas  31   a  and  31   b , respectively. Furthermore, the thickness of portions of the dielectric window  30  where the recesses  112  are formed is set to be smaller than that of the other portion of the dielectric window  30 . 
     In accordance with the ninth embodiment, the circular ring-shaped or circular protrusions  111  having the magnetic permeability different from that of the dielectric window  30  are provided on the top surface of the dielectric window  30  so as to correspond to the inter-position of the RF antennas  31   a  and  31   b . Further, the recesses  112  are formed in the bottom surface of the dielectric window  30  so as to correspond to the respective RF antennas  31   a  and  31   b . Furthermore, the thickness of the portions where the recesses  112  are formed is set to be smaller than that of the other portion of the dielectric window  30 . Therefore, the magnetic force lines may be cut by the protrusions  111  having the magnetic permeability different from that of the dielectric window  30  and the plasma may be generated directly under the RF antennas by induced magnetic fields stronger than the combined magnetic field by thinning the dielectric window  30 . Accordingly, due to the synergy effect of the above, it is possible to generate plasma  113  corresponding to the respective RF antennas  31   a  and  31   b.    
       FIG. 13  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a tenth embodiment of the present disclosure. 
     As illustrated in  FIG. 13 , a plasma processing apparatus  120  includes both the inventive feature of the second embodiment and the inventive feature of the first embodiment. That is, circular ring-shaped or circular protrusions  121  made of a dielectric material are provided on a bottom surface of the dielectric window  30  so as to correspond to the inter-position of the RF antennas  31   a  and  31   b . Further, recesses  122  are formed in the bottom surface of the dielectric window  30  so as to correspond to the respective RF antennas  31   a  and  31   b . A thickness of portions of the dielectric window  30  where the recesses  122  are formed is set to be smaller than that of the other portion of the dielectric window  30 . 
     In accordance with the tenth embodiment, the circular ring-shaped protrusions  121  are provided on the bottom surface of the dielectric window  30  so as to correspond to the inter-position of the RF antennas  31   a  and  31   b . The circular ring-shaped recesses  122  are also formed in the bottom surface of the dielectric window  30  so as to correspond to the respective RF antennas  31   a  and  31   b . Further, the thickness of the portions of the dielectric window  30  where the recesses  122  are formed is set to be smaller than that of the other portion of the dielectric window  30 . Therefore, plasma may be prevented from existing at a position where a combined magnetic field may be formed by the protrusions  121  made of the dielectric material. Further, plasma may be formed directly under the RF antennas by induced magnetic fields stronger than the combined magnetic field by thinning the dielectric window  30 . Due to the synergy effect of the above, it is possible to generate plasma  123  corresponding to the respective RF antennas  31   a  and  31   b . Thus, it is much easier to control the plasma within the chamber  11 , as in the above-described embodiments. 
       FIG. 14  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with an eleventh embodiment of the present disclosure. 
     As depicted in  FIG. 14 , a plasma processing apparatus  130  includes both the inventive feature of the first embodiment and the inventive feature of the fourth embodiment. That is, the RF antenna  31   c  having a diameter larger than the RF antenna  31   b  is provided within a chamber so as to be located outside the dielectric window  30 . Further, circular ring-shaped protrusions  131  made of a dielectric material are provided on a bottom surface of the dielectric window  30  at positions corresponding to the inter-position of the RF antennas  31   a  to  31   c.    
     In accordance with the eleventh embodiment, plasma may be prevented from existing at a position where a combined magnetic field may be formed by the protrusions  131  made of the dielectric material. Further, the combined magnetic field may not be generated by locating the RF antenna  31   c  in the chamber  11  so as to be distanced apart from the RF antenna  31   b . Due to the synergy effect of the above, it is possible to generate plasma  132  corresponding to the respective RF antennas  31   a  to  31   c . Thus, as in the above-described embodiments, it is much easier to control the plasma within the chamber  11 . 
     In the eleventh embodiment, although the RF antennas  31   b  and  31   c  are connected with the same high frequency power supply  33   b , it may be also possible to provide the high frequency power supplies for the respective RF antennas  31   b  and  31   c.    
       FIG. 15  is a cross sectional view schematically illustrating a major configuration of a plasma processing apparatus in accordance with a twelfth embodiment of the present disclosure. 
     As shown in  FIG. 15 , a plasma processing apparatus  140  includes all of the inventive features of the first to the fifth embodiment. That is, the dielectric window  30  is divided into the dielectric window  30   a  in the central portion of the chamber  11  and the dielectric window  30   b  in the inner peripheral portion of the chamber  11 . Further, a metal  141 , which is grounded, is disposed between the dielectric windows  30   a  and  30   b . Circular ring-shaped or circular protrusions  142  made of a dielectric material are provided on a bottom surface of the dielectric window  30   a  at positions corresponding to the inter-position of the RF antennas  31   a  and  31   b . Further, circular ring-shaped or circular protrusions  143  made of a material having a magnetic permeability different from that of the dielectric window  30   a  are provided on a top surface of the dielectric window  30   a . In addition, recesses  144  are formed at bottom surfaces of the dielectric windows  30   a  and  30   b  so as to correspond to the respective RF antennas  31   a  to  31   c . The thickness of portions of the dielectric windows  30   a  and  30   b  where the recesses  144  are formed is set to be smaller than that of the other portions of the dielectric windows  30   a  and  30   b . Furthermore, a RF antenna  31   d  having a diameter larger than the RF antenna  31   c  provided on the dielectric window  30   b  is provided within the chamber  11  so as to be located outside the dielectric window  30   b.    
     In accordance with the twelfth embodiment of the present disclosure, the plasma processing apparatus  140  have all the inventive features of the first to the fifth embodiments. Thus, due to the synergy effects of those inventive features, it is possible to generate plasma  145  in one-to-one correspondence to the respective RF antennas  31   a  to  31   d , accurately. Accordingly, as in the other embodiments as described above, it is much easier to control a plasma distribution within the chamber  11 . 
     In the twelfth embodiment, although the RF antennas  31   a  and  31   b  are connected with the same high frequency power supply  33   a , and the RF antennas  31   c  and  31   d  are connected with the same high frequency power supply  33   b , it may be also possible to provide the high frequency power supplies for the respective RF antennas  31   a  to  31   d . That is, a method for applying high frequency powers may not be particularly limited. Furthermore, a method for dividing the dielectric window may not also be particularly limited. 
     In the aforementioned embodiments, the substrate on which the plasma process is performed may not be limited to a glass substrate for a liquid crystal display (LCD), but various kinds of substrates for use in, e.g., an electro luminescence (EL) display and a flat panel display (FPD) such as a plasma display panel (PDP) may also be used.