Abstract:
Embodiments of the invention provide methods and apparatus to process substrates such as flat panel displays, solar panels, etc. In one aspect, the apparatus provides external toroidal plasma generation to perform substrate processes such as deposition and etching of rectangular-shaped substrates. In another aspect, the apparatus provides external toroidal plasma generation to perform chamber cleaning by flowing plasma of a process gas such as argon through a toroidal plasma current path that includes a processing region to be cleaned, introducing a cleaning gas such as fluorine into the processing region from a showerhead apparatus, and cleaning the processing region. In still another aspect, a toroidal plasma loop is shaped by a plasma shaping apparatus to direct the plasma across a processing region within the apparatus to improve process uniformity.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The invention relates to a method and apparatus for substrate processing. More specifically, the invention relates to a method and apparatus for performing processing steps such as deposition and/or etching of a substrate and/or process chamber cleaning.  
           [0003]    2. Background of the Related Art  
           [0004]    In the fabrication of integrated flat panel displays (FPD) and solar cells, electrically functional devices are formed by depositing and removing multiple layers of conducting, semiconducting, and dielectric materials from a substrate. Processing techniques used to create FPDs and solar cells can include chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), physical vapor deposition (PVD), etching, and the like.  
           [0005]    Plasma processing is particularly well suited for the production of integrated flat panels because of the relatively lower processing temperatures required to deposit films having good film quality. Generally, plasma-processing applications can be characterized by the kinetic energy of the ions in plasma, and by the level of direct exposure of the substrate or film being processed to the plasma. For example, applications sensitive to substrate or film damage generally require low-kinetic energy ions from the plasma, while applications such as anisotropic etching of silicon dioxide require ions with higher kinetic energy.  
           [0006]    The basic methods for plasma processing include DC discharge, RF discharge, and microwave discharge. One example of a plasma-processing chamber places the substrate on a substrate support having an electrode opposite a planar electrode. The planar electrode is used to couple high frequency power to the electrode to form a plasma between the electrode and the planar electrode. However, some devices or materials are not compatible with this type of plasma formation particularly because the plasma includes high-energy photons that cause undesirable substrate heating. To overcome this issue, another approach to plasma processing generates plasma in a remote location i.e., in a remote plasma source, (RPS) and couples the plasma to the processing chamber. Various types of remote plasma generators have been developed including magnetron sources coupled to a cavity, microwave irradiation directed at the plasma precursor, and others. Unfortunately, a portion of the energy within the plasma is lost to the conduits used to transport the plasma from the remote location which may affect the substrate processing efficiency.  
           [0007]    Conventional inductively coupled RF plasma sources are often used because they can generate large-area plasmas and generally have a higher processing rate than capacitively coupled sources and most remote plasma sources. In principle, inductively coupled plasma systems permit generation of high-density plasma in one portion of the processing chamber (e.g., above the substrate being processed) and sufficiently far away that the substrate is not directly exposed to the plasma.  
           [0008]    External toroidal plasma systems have been developed to further shield the substrate from plasma generation, provide a more uniform plasma across the substrate surface, and to overcome the disadvantages of the conventional inductively coupled plasma sources. One such system is described in U.S. patent application Ser. No. 09/638,075 entitled “Externally Excited Toroidal Plasma Source” filed Aug. 11, 2000. In this case, plasma is created within one or more conduits that extend externally from and are coupled to a processing region within a processing chamber. The conduits and processing region define a closed plasma loop (e.g., toroidal) path. The plasma and plasma currents are bound within the path by plasma sheaths formed at the various conductive surfaces that include the substrate and the adjacent walls of the processing region and the inner conduit surfaces.  
           [0009]    Conventional toroidal plasma processing systems used for processes such as etching have proven effective on smaller size round substrates up to about 300 mm. Generally, the plasma current flow through the toroidal processing region is constrained between an upper chamber surface sheath and the substrate to cover more substrate surface area, thereby minimizing the amount of plasma needed and maximizing the plasma energy used. However, the efficient use of toroidal plasma processing systems to process substrates is detrimentally affected by the increasing size of substrates. The problems associated with toroidal plasma processing systems are particularly dramatic on rectangular shaped substrates having surface areas approaching a square meter, such as FPDs, solar panels, and the like. As substrates increase in size, the plasma current path distance and surface area coverage increases resulting in an increase in plasma current resistance. In addition, the increasing size of substrates adversely affects plasma density uniformity. As the substrate size is increased, plasma density uniformity becomes increasingly difficult to maintain causing processing problems such as non-uniform deposition and etching. For example, deposition may be unacceptably thick or thin on the edges and near the corners effectively reducing the usable substrate surface area.  
           [0010]    Over time, process cycles (e.g., deposition and etching) leave a residue on chamber components. In some cases, this residue can interfere with the process being performed in the chamber and result in defective substrates. Accordingly, process chambers require periodic cleaning to ensure proper operation. One common way to accomplish this is to use a plasma-excited gas mixture that reacts with the residue, turning it into a volatile compound that can then be flushed from the system in preparation for the next substrate process. Often, a cleaning plasma is provided by biasing a pair of electrodes (typically, a showerhead and a substrate support member) to capacitively couple energy into a processing region of the processing chamber. Unfortunately, under direct exposure to the plasma, the showerhead and substrate support member can become damaged by the ions of the plasma. Damage to the chamber components often reduces subsequent processing effectiveness and requires additional processing chamber maintenance, thereby increasing production cost.  
           [0011]    Because of this issue, it has recently become more common to remotely-excite the cleaning gas in a volume that is physically removed from the processing electrodes. However, this practice comes with its own limitations as the excited reactants are remotely generated they must therefore be transported some distance to the processing volume to be effective in cleaning the residue from the processing system. This transport distance can be minimized as much as possible but still some of the reactants will become de-activated due to the inevitable wall interactions they unavoidably undergo along the way. Therefore, there is a need for method and apparatus to provide uniform plasma processing, including efficient cleaning, within a substrate processing system adapted to process large area substrates.  
         SUMMARY OF THE INVENTION  
         [0012]    Aspects of the invention generally provide an apparatus and method to perform plasma processing such as deposition, etching, and chamber cleaning. In one embodiment, a chamber comprises a body, a bottom, a lid, and a substrate support member disposed within the chamber. The lid, substrate support, and body define a processing region coupled to a pump adapted to maintain gas pressure therein. The chamber further comprises a RF source provided to excite plasma therein. An external structure defines a first toroidal plasma current path extending through the processing region and at least one plasma shaping apparatus is disposed within the first toroidal plasma current path to direct plasma distribution within the processing region.  
           [0013]    In another embodiment, the invention provides a plasma generating system, comprising a first hollow member defining a first plasma current path and a second hollow member defining a second plasma current path disposed substantially crosswise with respect to the first hollow member. A first electromagnetic source is disposed along a least a portion of the first hollow member and adapted to produce a first magnetic field within the first hollow member. A second electromagnetic source is disposed along a least a portion of the second hollow member and adapted to produce a second magnetic field within the second hollow member. The plasma generating system also includes a first plasma shaping apparatus disposed on at least one end of the first hollow member, and a second plasma shaping apparatus disposed on at least one end of the second hollow member.  
           [0014]    In another embodiment, the invention provides a plasma shaping apparatus, comprising a body, including an inner surface defining a symmetrical opening to allow plasma current flow therethrough where the opening has a cross section of varying dimensions to affect the density distribution of plasma current flowing through the opening.  
           [0015]    In another embodiment, the invention provides a method of substrate processing, comprising flowing a first gas into a first plasma current path defined by a first hollow member located external to a processing region, applying power to a first antenna adjacent the hollow member in order to inductively couple energy into the first plasma current path to provide a first plasma current and to generate a first plasma from the first gas. The method further includes flowing the first plasma current through a processing region adjacent a substrate and through another end of the first hollow member to define a first closed plasma current path. The method further includes flowing a process gas through a showerhead into the processing region and generating a plasma of the process gas adjacent the substrate using the plasma of the first gas. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    So that the manner in which the above recited features, advantages and aspects of the invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings.  
         [0017]    It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.  
         [0018]    [0018]FIG. 1 is a plan-view of a large-area plasma-processing tool.  
         [0019]    [0019]FIG. 2 is a top perspective view of a processing chamber of the large-area plasma-processing tool of FIG. 1.  
         [0020]    [0020]FIG. 3 is a top view illustrating a processing chamber of the large-area plasma-processing tool of FIG. 1.  
         [0021]    [0021]FIG. 4 is side view of illustrating a processing chamber of the large-area plasma-processing tool of FIG. 1.  
         [0022]    [0022]FIG. 5 is a cutaway side view illustrating a processing chamber of the large-area plasma-processing tool of FIG. 1.  
         [0023]    [0023]FIGS. 6A and 6B are top and side views respectively illustrating one type of coil antenna arrangement.  
         [0024]    [0024]FIGS. 7A and 7B are top and side views respectively illustrating one type of coil antenna arrangement.  
         [0025]    [0025]FIG. 8 is a side view of a plasma shaping apparatus.  
         [0026]    [0026]FIG. 9 is a side view of a plasma shaping apparatus.  
         [0027]    [0027]FIG. 10 is a side view of a plasma shaping apparatus.  
         [0028]    [0028]FIG. 11 is a top view of a processing chamber of the large-area plasma-processing tool of FIG. 1 including four magnetic plasma shaping apparatuses.  
         [0029]    [0029]FIGS. 12A and 12B are top and side views illustrating one embodiment of an electromagnetic plasma shaping apparatus of FIG. 11.  
         [0030]    [0030]FIGS. 13A and 13B are top and side views illustrating one embodiment of an electromagnetic plasma shaping apparatus of FIG. 11.  
         [0031]    [0031]FIGS. 14A and 14B are top and side views illustrating one embodiment of a magnetic plasma shaping apparatus of FIG. 11.  
         [0032]    [0032]FIGS. 15A and 15B are top and side views illustrating one embodiment of a magnetic plasma shaping apparatus of FIG. 11.  
         [0033]    [0033]FIGS. 16A and 16B are top and side views illustrating one embodiment of a magnetic plasma shaping apparatus of FIG. 11.  
         [0034]    [0034]FIGS. 17A and 17B are top and side views illustrating one embodiment of a magnetic plasma shaping apparatus of FIG. 11.  
         [0035]    [0035]FIGS. 18A and 18B are a top and side view illustrating one embodiment of a magnetic plasma shaping apparatus of FIG. 11.  
         [0036]    [0036]FIGS. 19A and 19B are top and side views illustrating one embodiment of a magnetic plasma shaping apparatus of FIG. 11.  
         [0037]    [0037]FIGS. 20A and 20B are top and side views illustrating one embodiment of a magnetic plasma shaping apparatus of FIG. 11.  
         [0038]    [0038]FIGS. 21A and 21B are top and side views illustrating one embodiment of a magnetic plasma shaping apparatus of FIG. 11. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0039]    Aspects of the invention have particular advantages in a multi-chamber processing system, also known as a cluster tool, which is commonly used in the semiconductor industry. Additionally, aspects of the invention are and well suited for supporting the toroidal substrate plasma-processing chamber described herein. A cluster tool is a modular system comprising multiple chambers that perform various functions including substrate heating, center-finding and orientation, annealing, deposition, etching, and the like. The multiple chambers are mounted to a central transfer chamber which houses a robot adapted to shuttle substrates between the chambers. The transfer chamber is typically maintained at a vacuum condition and provides an intermediate stage for shuttling substrates from one chamber to another and/or to a load lock chamber positioned at a front end of the cluster tool.  
         [0040]    [0040]FIG. 1 is a plan view of a processing system  100  for semiconductor processing. The processing system  100  generally comprises a plurality of chambers and robots and is preferably equipped with a process system controller  102  programmed to carry out the various processing methods performed in the processing system  100 . A front-end environment  104  is shown positioned in selective communication with a pair of load lock chambers  106 . Pod loaders  108 A-B disposed in the front-end environment  104  are capable of linear, rotational, and vertical movement to shuttle substrates between the load locks  106  and a plurality of substrate cassettes  105  which are mounted on the front-end environment  104 .  
         [0041]    The load locks  106  provide a first vacuum interface between the front-end environment  104  and a transfer chamber  110 . Two load locks  106  are provided to increase throughput by alternatively communicating with the transfer chamber  110  and the front-end environment  104 . Thus, while one load lock  106  communicates with the transfer chamber  110 , a second load lock  106  may communicate with the front-end environment  104 . A robot  113  is centrally disposed in the transfer chamber  110  to transfer substrates from the load locks  106  to one of the various processing chambers  114  or holding chambers  116 . The processing chambers  114  are adapted to perform any number of processes such as film deposition, annealing, etching, while the holding chambers  116  are adapted for processes such as orientation and cool down.  
         [0042]    [0042]FIGS. 2, 3, and  4  are a top perspective view, top view, and side view, respectively, illustrating one embodiment of a processing chamber  114 . In general, the processing chamber  114  has a polygonal shape in order to accommodate polygonal shaped substrates. The processing chamber  114  includes a body  116  having an opening  156  formed therein and shaped to accommodate the transfer of substrates into and out the processing chamber  114  by operation of the robot  113  (shown in FIG. 1). The opening  156  is selectively sealed by a sealing mechanism such as a gate valve or slit valve apparatus (not shown). Illustratively, only one opening  156  is shown. However, in other embodiments, two or more openings may be provided to allow access to the chamber through other chamber walls.  
         [0043]    The processing chamber  114  further includes a first external hollow conduit  124  and a second external conduit  125  adapted to hold a process and/or cleaning gas therein. The gases are provided to the first and second hollow conduits  124 ,  125  via conduit gas inlets  111 ,  123 , respectively. The conduits  124 ,  125  may be coupled to one or more external gas sources (not shown) containing gases such as argon, helium, hydrogen, oxygen, NF 3 , and like. The conduits  124 ,  125  may be formed of a relatively thin conductor such as, aluminum, anodized aluminum, stainless steel, polymers, ceramics, and the like, sufficiently strong to withstand a vacuum therein.  
         [0044]    The first external hollow conduit  124  and second external hollow conduit  125  are disposed over and traverse a lid  118  of the processing chamber  114 . The conduits  124 ,  125  are aligned generally orthogonal and are disposed above one another where the first conduit  124  is taller with respect to the lid  118  to allow the second conduit  125  to pass between the lid  118  and the first conduit  124 . In one aspect, the conduits  124 , 125  are coupled to the body  116  using fasteners such as screws, bolts, and the like. The first and second conduits  124 ,  125  are coupled to an internal processing cavity of the processing chamber  114  discussed below with reference to FIG. 5. Although shown extending externally outward from the processing chamber  114  as separate components, the first and second conduits  124 ,  125  may be formed integrally to the lid  118 .  
         [0045]    First and second coil antennas  137 ,  138  are disposed proximate the conduits  124 ,  125 , respectively and are adapted to couple RF energy into a process gas and/or cleaning gas within each respective conduit  124 ,  125 . The RF energy excites the gas within each respective conduit  124 ,  125  to form plasma therein. The details and operation of the conduits  124 ,  125 , the coil antennas  137 ,  138 , and the processing chamber  114  will be discussed below with respect to FIG. 5. While the coil antennas  137 ,  138  may be used to couple RF energy into the conduits  124 ,  125 , it is contemplated that the RF energy can also be coupled into the plasma within the conduits  124 , 125  using magnetic-flux-concentrating materials such as ferrites.  
         [0046]    [0046]FIG. 5 is a cross-section of one embodiment of a processing chamber  114 . FIGS.  1 - 4  may be referenced as needed with the discussion of FIG. 5. The processing chamber  114  includes a processing chamber body  116  and lid  118 . The processing chamber body  116  and lid  118  define a cavity within the processing chamber  114  that includes a processing region  120  therein. A showerhead  122  disposed within the lid  118  defines the upper boundary of the processing region  120 . The showerhead  122  comprises a gas inlet  117  and a plurality of dispersion holes  121  to allow delivery of one or more processing gases such as SiH 4 , N 2 O, NH 3 , CH 4 , TEOS, O 2 , H 2 , He, WF 6 , NF 3 , CF, C X H Y F Z , C x F y , Trimethylsilane (TMS), therethrough into the processing region  120 . In one aspect, the showerhead  122  acts as an anode coupled to a showerhead RF source  119  and matching network  128  to capacitvely couple RF energy to the processing region  120 .  
         [0047]    The processing chamber  114  also includes a movable substrate support member  130 , also referred to as a susceptor, which can be raised or lowered in the processing chamber  114  by a lifting apparatus  133 . A substrate support surface  131  of the substrate support member  130  defines the lower boundary of the processing region  120 . The substrate support member  130  may be heated using resistive heaters, lamps, or other heating devices commonly used in the field of electronic device fabrication. A shaft  132  of the substrate support member  130  is moveably disposed through a floor of the body  116 . In one aspect, an insulating o-ring  144  located in the floor and disposed around the shaft  132  can be used to electrically isolate the support member  130  while also providing a vacuum seal. In one aspect, a bellows  156  is coupled to an upper sealing ring  157 A, disposed on the body  116 , and is also coupled to lower sealing ring  157 B disposed about the shaft  132  to provide an alternative vacuum seal. The substrate support  130  can then be coupled to a bias RF source  146  through a matching network  147 . In operation, the bias RF source  146  is adjusted to vary the attraction of ion species toward the substrate.  
         [0048]    In one aspect, the lid  118  includes an exhaust port  142  defined by a peripherally-mounted plenum structure  143  attached to and circumventing the perimeter of the lid  118  to allow process gases to be evacuated from the processing region  120 . An insulating ring  155  electrically insulates the peripherally-mounted plenum structure  143  and lid  118  from the showerhead  122 . A vacuum pump  139  is coupled to the processing chamber  114  to control the chamber pressure therein. The vacuum pump  139  may be any pump adapted to achieve and maintain a desired pressure. Illustrative pumps that may be used to advantage include turbopumps, cryo pumps, roughing pumps, and any combination thereof. Illustratively, the vacuum pump  139  communicates with the processing chamber  114  via an exhaust coupling  140 . Specifically, the exhaust coupling  140  is connected at one end to the vacuum pump  139  and at another end to the plenum structure  143 . While, a pumping position is shown where the gases are evacuated from the lid  118  forming a top-pumping configuration, it is contemplated that the vacuum pump could be coupled to the cavity from any location. For example, the vacuum pump  139  may be coupled to the bottom of the body  116  through a bottom exhaust port (not shown) forming a bottom-pumping configuration.  
         [0049]    The first and second external hollow conduits  124 , 125  are disposed in alignment with a first opening pair  170 A-B and second opening pair  171 A-B formed within the body  116  to couple the conduits  124 ,  125  to the processing region  120  therein. The first w and second opening pairs  170 A-B,  171 A-B are generally axially aligned on opposite sides of the substrate support  130  and are positioned such that during processing they define a plasma current path extending across the processing region  120  and between the substrate support member  130  and showerhead  122 . Internally, each conduit  124 , 125  shares the same evacuated atmosphere as exists elsewhere in the chamber cavity, including the processing region  120 . During operation, the conduits  124 , 125  provide an external plasma current flow path from the processing region  120  and are coupled to the internal plasma current paths extending across the processing region via the first and second opening pairs  170 A-B,  171 A-B respectively. Thus, the conduits  124 ,  125  and the internal processing region  120  define two separate toroidal plasma current paths providing plasma current ingress into and egress from the processing chamber  114 . Illustratively, the first conduit  124  and processing region  120  define a first toroidal plasma current path  160 . The second conduit  125  and processing region  120  define a second toroidal plasma current path  161 . Notwithstanding the use of the term “toroidal”, the trajectory of the closed path through each conduit  124 ,  125  and the processing region  120  may be circular, non-circular, square, rectangular, or any other shape either regular or irregular. Illustratively, the conduits  124 ,  125  and the toroidal plasma current paths  160 - 161  are generally rectangular in cross section but may be any other cross-sectional shape such as polygon, circular, elliptical and the like.  
         [0050]    In one aspect, to ensure substantially equal plasma density, it is desirable to keep the plasma current paths  160 - 161  about the same length by adjusting the conduits  124 , 125  lengths. As the substrates and therefore the processing chamber  114  are often rectangular in shape, the narrower width of the processing chamber  114  relative to its length makes it desirable to position the first hollow conduit  124 , which spans the width, above the second hollow conduit  125 .  
         [0051]    In another aspect, the first and second hollow conduits  124 ,  125  are generally narrower in width than the processing chamber  114  to facilitate inductive coupling of the excitation source energy to the plasma inside the conduit. Therefore, to mate with the first and second opening pairs  170 A-B and  171 A-B the first and second hollow conduits  124 ,  125  increase in width from a narrower upper member  124 A,  125 A to two wider lower ends  124 B-C,  125 B-C, that are adapted to mate with their respective opening pairs  170 A-B,  171 A-B. For example, the first hollow conduit  124  is registered with and coupled on a first lower end  124 B-C, to the first inlet pair  170 A-B. The second hollow conduit  125  is registered with and coupled on a second lower end  125 B-C, to the second inlet pair  171 A-B.  
         [0052]    In one aspect, the first coil antenna  137  includes one or more turns about a longitudinal axis and is adapted to couple energy (illustratively RF energy) into the first conduit  124  from a first inductive RF source  125  through a matching network  126 . The longitudinal axis of the first coil antenna  137  is disposed generally orthogonal to the longitudinal axis of the first conduit  124 . The second coil antenna  138  includes one or more turns about a longitudinal axis and is adapted to couple energy (illustratively RF energy) into the second conduit  125  from a second inductive RF source  129  through an optional matching network  127  for better power utilization efficiency. The longitudinal axis of the second coil antenna  138  is disposed generally orthogonal to the longitudinal axis of the second conduit  125 . While each coil antenna  137 ,  138  is wound in a generally flat elliptical shape that extends along a length of a respective conduit  124 ,  125 , it is contemplated that the coil antennas  137 ,  138  can be of any shape or length adapted to couple RF energy into the respective first or second conduits  124 ,  125 .  
         [0053]    Each coil antenna  137 , 138  forms a primary transformer turn and the toroidal plasma current paths  160 - 161  define a secondary transformer turn, respectively. For example, the first coil antenna  137  forms a primary transformer turn and the plasma within the first toroidal path  160  forms a secondary transformer turn. In order to prevent electrically-conductive hollow conduits  124 , 125 , from shorting the electric field generated by the magnetic field of the coil antennas (and thereby eliminating the possibility of generating a plasma within the conduits) an insulating gap  153  (only one gap is shown) extends across each hollow conduit  124 , 125 . The gaps  153  are enclosed by a ring  154  of insulating material such as ceramic, glass, and the like adapted to provide electrical insulation while maintaining vacuum integrity of the conduits  124 ,  125 . Alternatively, the hollow conduits  124 , 125  may be formed from a non-conductive material such as ceramic, glass, and the like, to eliminate any electric paths altogether without the need for the gaps  153 .  
         [0054]    In one aspect, the first and second coil antennas  137 ,  138  are wound so the currents within the coil antennas  137 ,  138  are about parallel to the plasma current flow within the respective first and second plasma current paths  160 , 161 . As a result, the magnetic fields produced by the currents within each antenna coil  137 ,  138  are generally orthogonal to the direction of current flow through the first and second plasma current paths, respectively.  
         [0055]    While the axial alignment of each coil  137 ,  138  relative to their respective conduits  124 ,  125  aligns the currents within the coil antennas  137 ,  138  to their respective plasma currents, the coil antennas  137 ,  138  may be placed in any position to achieve a desired plasma energy density. For example, the coil antennas  137 ,  138  may be wound such that the axis of the coil antennas  137 ,  138  are generally orthogonal to the longitudinal axis of their respective conduits  124 ,  125 . Illustratively, FIGS. 6A and 6B depict one aspect whereby the first coil antenna  137  is wound such that the axis of the first coil antenna  137  is generally orthogonal to the longitudinal axis of its respective conduit  124 . In another aspect, a portion of each antenna coil  137 ,  138  is wound on opposing sides of their respective conduits  124 ,  125  to enhance the energy coupling. For example, FIG. 6B illustrates the first coil antenna  137  wound on opposing sides of its conduit  124 .  
         [0056]    The coil antennas  137 ,  138 , may also be wound in a helical flat winding, such that the windings are in closer proximity to the conduits  124 ,  125 , thereby increasing the RF energy coupled into the plasma. For example, FIGS. 7A and 7B illustrate another configuration whereby the first coil antenna  137  is wound in a flat helical shape and whereby the longitudinal axis of the first coil antenna  137 ,  138 , is aligned generally orthogonal to the longitudinal axis of their respective conduits  124 ,  125 . The energy coupling into the plasma may also be increased by positioning the conduit between the windings so that a portion of the coil antenna  137 ,  138  are on opposing sides of the conduit  124 ,  125 . For example, FIG. 7B illustrates the first coil antenna  137  is wound as a flat helical shape on opposing sides of the first conduit  124 .  
         [0057]    Referring back to FIG. 5, in one aspect, to provide a uniform coverage of the substrate surface, the toroidal plasma current paths  160 , 161  are aligned generally orthogonal so that the plasma from the first plasma current path  160  crosses processing region  120  generally orthogonal to the second plasma current path  161 . The toroidal plasma current paths  160 - 161  are generally constrained within their respective conduits  124 ,  125 , however, it is contemplated that the plasma formed in the shared volume above the substrate within the processing region  120  will allow “leakage” of currents between the plasma current paths  160 ,  161 . To some extent this plasma leakage will aid in achieving a uniform plasma density in the shared volume above the substrate, however, it must be controlled to the extent necessary to affect uniform deposition and etching. In one aspect, to control the amount of plasma leakage between the first path  160  to the second path  161 , a first plasma shaping apparatus pair  150 A-B is disposed within the first opening pair  170 A-B. Each member of the first plasma shaping apparatus pair  150 A-B are aligned to generally face the other member across the processing region  120 . In order to control the amount of plasma leakage from the second path  161  to the first path  160 , a second plasma shaping apparatus pair  151 A-B is disposed within the second opening pair  171 A-B. Each member of the second plasma shaping apparatus pair  150 A-B are aligned to generally face the other member across the processing region  120 . The function of the plasma shaping apparatuses  150 A-B,  151 A-B is also to ensure that the natural tendency of the plasma in each toroidal plasma current loop  160 , 161  to take the shortest possible (minimum resistance) path across the shared volume does not result in the plasma being confined to narrow “bands” across mutually-orthogonal median lines of the volume. For example, if the plasma current density was greater along the middle of the substrate, the deposition or etch process would be exaggerated across the substrate middle affecting the process uniformity.  
         [0058]    The first conduit  124 , the first opening pair  170 A-B, and the first plasma shaping apparatus pair  150 A-B define a first external structure  149 A representing a portion of the first toroidal plasma current path  160 . The second conduit  125 , the second opening pair  171 A-B, and the second plasma shaping apparatus pair  151 A-B define a second external structure  149 B representing a portion of the second toroidal plasma current path  161 . While the first and second plasma shaping apparatus pair  150 A-B,  151 A-B, are disposed within the first and second opening pair  170 A-B,  171 A-B, respectively, it is contemplated that the first and second plasma shaping apparatus pair  150 A-B,  151 A-B may be positioned in any location along the respective paths  160 ,  161 . For example, the first and second plasma shaping apparatus pair  150 A-B,  151 A-B, may be disposed to the first and second lower ends  124 B-C,  125 B-C, of the conduits,  124 ,  125 , or may be a coupling member adapted to couple the lower ends  124 B-C,  125 B-C, to the body  116  adjacent the opening pairs  170 A-B,  171 A-B.  
         [0059]    Each member of the plasma shaping apparatus pairs  150 A-B,  151 A-B has an opening, the shape of which in turn determines the distribution of the plasma within the volumes on either side of the apparatus pairs  150 A-B,  151 A-B. The current produced by the induced electric field, which creates and sustains the plasma in each toroidal plasma current path  160 ,  161 , is constricted by the smaller portions of the opening to alter the plasma distribution within the processing region  120 . In one aspect, the plasma shaping apparatus pairs  150 A-B,  151 A-B are formed from material about ⅛″ inch to about ¼″ inch thick to provide a plasma constriction momentarily increasing the plasma current density. In general, the plasma shaping apparatus pairs  150 A-B,  151 A-B are formed of metallic materials such as aluminum, stainless steel, anodized aluminum.  
         [0060]    In one aspect, the plasma shaping apparatus pairs  150 A-B,  151 A-B are adapted to be changeable between and/or during a process to create different plasma current flow patterns across the processing region  120 . For example, FIG. 8 illustrates one embodiment for one member  150 A of the first plasma shaping apparatus pair  150 A-B having a larger center cross sectional area  166 A and two outer smaller regions  167 A. The inner periphery  163 A acts to define a desired plasma current distribution in the processing region  120  by creating a distributed impedance to the current flowing in the plasma. A higher current density at the center  166 A of the opening may be used, for example, to increase the deposition along the central region of the substrate parallel to the current flow through the plasma shaping apparatus pair  150 A-B.  
         [0061]    [0061]FIG. 9 illustrates another embodiment of one member  150 A of the first plasma shaping apparatus pair  150 A-B where an inner periphery  163 B defines a narrowed center portion  166 B and two larger outer portions  167 B that are generally opposite each other and on either side of the center portion  166 B. As the plasma current flows through the opening, the constriction at the center portion  166 B forces more of the plasma current through the wider portions of the opening  167 B thereby decreasing plasma density along the middle of the plasma current flow within the processing region  120 . During substrate processing, decreasing the plasma density along the middle of the plasma current flow decreases the deposition or etching rate along the middle of the substrate.  
         [0062]    It is contemplated that the inner periphery  163 A-B may be adapted to establish any opening to shape the plasma current flow into any desired density distribution. For example, FIG. 10 illustrates that outer portions  167 A-B and the center portion  166 A-B may define two or more openings  166 C that constrict the plasma current on the edges and the middle of the processing region. In another example, with regard to cleaning, the plasma shaping apparatus pairs  150 A-B and  151 A-B may be removed entirely. Additionally, the plasma shaping apparatus pairs  150 A-B and  151 A-B may be adapted to have a narrower or larger opening to accommodate smaller, or larger, substrates within the same chamber, respectively, or to control the amount of overall ion density distribution within the processing region  120 .  
         [0063]    In one embodiment, the plasma current flow may be shaped magnetically. FIG. 11 is a top view of one the processing chamber  114  including four magnetic plasma shaping apparatuses  180 A-D. In one aspect, each of the four magnetic plasma shaping apparatuses  180 A-D is disposed above and below and across the length of one of the wider lower ends  124 B-C,  125 B-C adjacent the chamber  114 . The four magnetic plasma shaping apparatuses  180 A-D are adapted to provide a magnetic field within the hollow conduits  124 ,  125  at the lower ends  124 B-C,  125 B-C, respectively, to form a magnetic opening to shape the plasma current flow therein.  
         [0064]    The magnetic plasma shaping apparatuses  180 A-D include a plurality of magnetic elements  184  such as electromagnets, permanent magnets, and the like, disposed above and/or below the first and second lower ends  124 B-C,  125 B-C. The magnetic elements are adapted to provide a desired magnetic field profile which in turn defines a plasma current flow profile within the lower ends  124 B-C,  125 B-C to control the plasma current flow through each path  160 - 161  through the processing region  120 . For example, by using a plurality of magnetic elements  184  having different magnetic field strengths and/or by varying the position of the magnetic elements  184  along the width and/or proximity to the plasma current therein of the lower ends  124 B-C,  125 B-C, a plurality of plasma current flow profiles may be formed. In one aspect, the magnetic elements  184  include one or more electromagnetic coils coupled to a DC power source, or sources (not shown), to set the level of the electromagnetic fields therein. It is contemplated that the strength of the current within each electromagnetic coil may be adjusted to alter the magnetic field profile to adjust and/or define a desired plasma current flow profile from process to process, or during a particular process.  
         [0065]    In one aspect, the magnetic poles of the magnetic elements  184  are set parallel to define a common magnetic field polarization with respect to the plasma, thereby minimizing plasma leakage to the walls of the hollow conduits  124 ,  125 . For example, the south pole of each magnetic element  184  is set orthogonal to and facing the plasma.  
         [0066]    It is contemplated that the magnetic poles may be set to any desired position or configuration to attain a desired magnetic field profile. For example, FIGS.  12 A-B through  21 A-B are cut away top and side views illustrating various configurations of a first magnetic plasma shaping apparatuses  180 A using magnetic elements  184  including electromagnetic coils and/or permanent magnets. While only one magnetic plasma shaping apparatus  180 A is shown, the FIGS.  12 A-B through  21 A-B illustrate only a few of the plurality of configurations for each of the four magnetic plasma shaping apparatuses  180 A-D.  
         [0067]    FIGS.  12 A-B illustrate one embodiment of the first magnetic plasma shaping apparatus  180 A. A plurality of electromagnetic coils  201 A-G varying in dimension are disposed above, below, and along the width of the first lower end  124 B and have their longitudinal axis aligned generally orthogonal to the first plasma current path  160 . In one aspect, a plurality of first electromagnetic coils  201 A-F are disposed above the first lower end  124 B. The first electromagnetic coils  201 A-F have their magnetic poles aligned with, adjacent, and juxtaposed to a plurality of second electromagnetic coils  201 G disposed below the first lower end  124 B. To form an opposing magnetic field, the magnetic poles of the first electromagnetic coils  201 A-F are generally aligned with and the same as poles of the second electromagnetic coils  201 G. Further, the magnetic north and south poles of adjacent discrete coils are adjacent. For example, the magnetic north pole of electromagnetic coil  201 A is facing and adjacent the magnetic south pole of the electromagnetic coil  201 B. Illustratively, the first electromagnetic coils  201 A-F provide an upper magnetic field  188 A adjacent the toroidal path  160 . The second electromagnetic coils  201 G provide a lower magnetic field  188 B adjacent the toroidal path  160  and below the upper magnetic field  188 A. The upper and lower magnetic fields  188 A,  188 B define a magnetic opening  189 A disposed adjacent the lower end  124 B. The magnetic opening  189 A is disposed within and about orthogonal to the plasma current path  160 .  
         [0068]    FIGS.  13 A-B illustrate another configuration of the first magnetic plasma shaping apparatus  180 A. A plurality of first electromagnetic coils  202 A are disposed above and below and along the width of the first lower end  124 B. The first electromagnetic coils  202 A have their longitudinal axis aligned generally orthogonal to the first plasma current path  160 . In one aspect, the plurality of first electromagnetic coils  202 A are disposed above the first lower end  124 B. The first electromagnetic coils  202 A have their magnetic poles aligned, are adjacent to, and juxtaposed the plurality of second electromagnetic coils  202 G disposed below the first lower end  124 B. To form an opposing magnetic field, the magnetic poles of the first electromagnetic coils  202 A are aligned with and the same type as the magnetic poles of the second electromagnetic coils  202 G (e.g., south poles are aligned). Further, the magnetic north and south poles of adjacent discrete coils are opposite. For example, the magnetic north pole of a first discrete electromagnetic coil  202 A′ is facing and adjacent the magnetic south pole of an adjacent second electromagnetic coil  202 A″. Illustratively, the first electromagnetic coils  202 A provide an upper magnetic field  188 C disposed adjacent the toroidal path  160 . The second electromagnetic coils  202 H provide a lower magnetic field  188 D disposed adjacent the toroidal path  160  and below the upper magnetic field  188 C. The upper and lower magnetic fields  188 C,  188 D define a magnetic opening  189 B disposed adjacent the lower end  124 B and generally disposed within and orthogonal to the plasma current path  160 .  
         [0069]    FIGS.  14 A-B illustrate another configuration of the first magnetic plasma shaping apparatus  180 A. A plurality of first and second electromagnetic coils  204 A-F of varying length are disposed along the width and above and below the first lower end  124 B and have their longitudinal axis aligned generally aligned with the first plasma current path  160 . In one aspect, the plurality of first electromagnetic coils  204 A-E disposed above the first lower end  124 B. The first electromagnetic coils  204 A-E have their magnetic poles aligned, adjacent to and juxtaposed the plurality of second electromagnetic coils  204 F disposed below the first lower end  124 B. To form an opposing magnetic field, the magnetic poles of the first electromagnetic coils  204 A-E are aligned with the magnetic poles of the second electromagnetic coils  204 F. Further, the magnetic north and south poles of adjacent discrete coils are aligned. For example, the magnetic north pole of a first discrete electromagnetic coil  204 A is aligned with the magnetic north pole of an adjacent second electromagnetic coil  204 B. Illustratively, the first electromagnetic coils  204 A-E provide an upper magnetic field  188 E disposed adjacent the toroidal path  160 . The second electromagnetic coils  202 F provide a lower magnetic field  188 F disposed adjacent the toroidal path  160  and below the upper magnetic field  188 E. The upper and lower magnetic fields  188 E,  188 F define a magnetic opening  189 C disposed adjacent the lower end  124 B and generally orthogonal to the plasma current path  160 .  
         [0070]    FIGS.  15 A-B illustrate another configuration of the first magnetic plasma shaping apparatus  180 A. A plurality of first and second electromagnetic coils  206 A-B are disposed above, below, and along the width of the first lower end  124 B and have their longitudinal axis aligned generally with the first plasma current path  160 . In one aspect, the plurality of first electromagnetic coils  206 A are disposed above the first lower end  124 B. The first electromagnetic coils  206 A have their magnetic poles aligned with the plurality of second electromagnetic coils  206 B disposed below the first lower end  124 B. To form an opposing magnetic field, the magnetic poles of the first electromagnetic coils  206 A are aligned with the magnetic poles of the second electromagnetic coils  206 B (e.g., south pole of the first coil opposite the south pole of the second coil). Further, the magnetic north and south poles of adjacent discrete coils are aligned. For example, the magnetic north pole of a first discrete electromagnetic coil  206 A′ is aligned with the magnetic north pole of an adjacent second electromagnetic coil  206 A″. Illustratively, the first electromagnetic coils  206 A provide an upper magnetic field  188 G disposed adjacent the toroidal path  160 . The second electromagnetic coils  206 H provide a lower magnetic field  188 H disposed adjacent the toroidal path  160  and below the upper magnetic field  188 G. The upper and lower magnetic fields  188 G,  188 H define a magnetic opening  189 D disposed adjacent the lower end  124 B and generally orthogonal to the plasma current path  160 .  
         [0071]    FIGS.  16 A-B illustrate another configuration of the first magnetic plasma shaping apparatus  180 A. A plurality of first and second electromagnetic coils  208 A-F are disposed above, below, and along the width of the first lower end  124 B and have their longitudinal axis aligned generally orthogonal to the first plasma current path  160 . In one aspect, the plurality of first electromagnetic coils  208 A-E are disposed above the first lower end  124 B and have their magnetic poles aligned adjacent to and juxtaposed the plurality of second electromagnetic coils  208 F disposed below the first lower end  124 B. To form an opposing magnetic field, the magnetic poles of the first electromagnetic coils  208 A-E are aligned with the magnetic poles of the second electromagnetic coils  208 F. Further, the magnetic north and south poles of adjacent discrete coils are aligned. For example, the magnetic north pole of a first discrete electromagnetic coil  208 A is aligned with the magnetic north pole of an adjacent second electromagnetic coil  208 B. Illustratively, the upper electromagnetic coils  208 A-E provide an upper magnetic field  1881  disposed adjacent the toroidal path  160 . The second electromagnetic coils  208 F provide a lower magnetic field  188 J disposed adjacent the toroidal path  160  and below the upper magnetic field  1881 . The upper and lower magnetic fields  188 I,  188 J define a magnetic opening  189 E disposed adjacent the lower end  124 B and generally orthogonal to the plasma current path  160 .  
         [0072]    FIGS.  17 A-B illustrates another configuration of the first magnetic plasma shaping apparatus  180 A. A plurality of first and second electromagnetic coils  210 A-D are disposed along the width of the first lower end  124 B and have their longitudinal axis aligned generally orthogonal to the first plasma current path  160 . In one aspect, the plurality of first electromagnetic coils  210 A-B disposed above the first lower end  124 B have their magnetic poles aligned and are adjacent to and juxtaposed the plurality of second electromagnetic coils  210 C-D disposed below the first lower end  124 B. To form an opposing magnetic field, the magnetic poles of the first electromagnetic coils  210 A-B are aligned with the magnetic poles of the adjacent second electromagnetic coils  210 C-D. Further, the magnetic north and south poles of the adjacent discrete coils  210 A-B and  210 C-D are opposed. For example, the magnetic north pole of a first discrete electromagnetic coil  210 A′ is aligned with the magnetic south pole of an adjacent second electromagnetic coil  210 B′. Still further, the magnetic north and south poles of adjacent first and second electromagnetic coils  210 A-D are opposing. For example, the magnetic south pole of the first discrete electromagnetic coil  210 A is opposite the south pole of an adjacent second electromagnetic coil  210 C. Illustratively, the plurality of first electromagnetic coils  210 A provides an upper magnetic field  188 K disposed adjacent the toroidal path  160 . The plurality of second electromagnetic coils  210 C-D provides a lower magnetic field  188 L disposed adjacent the toroidal path  160  and below the upper magnetic field  188 K. The upper and lower magnetic fields  188 K,  188 L define a magnetic opening  189 F disposed adjacent the lower end  124 B and generally orthogonal to the plasma current path  160 .  
         [0073]    FIGS.  18 A-B illustrate another configuration of the first magnetic plasma shaping apparatus  180 A. In one aspect, a plurality of first and second electromagnetic coils  212 A-B are disposed above, below, and along the width of the first lower end  124 B and have their longitudinal axis aligned generally orthogonal to the first plasma current path  160 . To form an opposing magnetic field, the plurality of first electromagnetic coils  212 A disposed above the first lower end  124 B have their magnetic poles aligned adjacent to and juxtaposed the plurality of second electromagnetic coils  212 B disposed below the first lower end  124 B. For example, the north pole of the first electromagnetic coils  212 A are aligned with the north poles of the second first electromagnetic coils  212 B. Further, the magnetic north and south poles of adjacent discrete coils are aligned. For example, the magnetic south pole of a first discrete electromagnetic coil  212 A′ is aligned with the magnetic south pole of an adjacent second electromagnetic coil  212 A″. Illustratively, the first electromagnetic coils  212 A provide an upper magnetic field  188 P disposed adjacent the toroidal path  160 . The second electromagnetic coils  212 B provide a lower magnetic field  188 Q disposed adjacent the toroidal path  160  and below the upper magnetic field  188 P. The upper and lower magnetic fields  188 P,  188 Q define a magnetic opening  189 G disposed adjacent the lower end  124 B and generally orthogonal to the plasma current path  160 .  
         [0074]    FIGS.  19 A-B illustrate another configuration of the first magnetic plasma shaping apparatus  180 A. A first and second electromagnetic coil  214 A-B having windings of varying lengths are disposed along the width of the first lower end  124 B and have their longitudinal axis aligned generally orthogonal to the first plasma current path  160 . In one aspect, to form an opposing magnetic field the first electromagnetic coil  214 A is disposed above the first lower end  124 B, has its magnetic pole aligned with the second electromagnetic coil  214 B disposed below the first lower end  124 B. The magnetic pole of the first electromagnetic coil  214 A is generally aligned with the magnetic pole of the second electromagnetic coil  214 B. Further, the magnetic poles of the first and second electromagnetic coils  214 A-B that face each other are the same. For example, the magnetic north pole of the first electromagnetic coil  214 A is opposite the magnetic north pole of the second electromagnetic coil  214 B. Illustratively, the first electromagnetic coils  214 A provide an upper magnetic field  188 R disposed adjacent the toroidal path  160 . The second electromagnetic coils  214 B provide a lower magnetic field  188 S disposed adjacent the toroidal path  160  and below the upper magnetic field  188 R. The upper and lower magnetic fields  188 R,  188 S define a magnetic opening  189 H disposed adjacent the lower end  124 B and generally orthogonal to the plasma current path  160 . In another aspect, the first and second coils may include a plurality of coils of varying length that are disposed upon each other and having their longitudinal axis aligned. For example, the first electromagnetic coil  214 A may comprise six windings of varying length, each of which is a separate coil with the longitudinal axis of each of the six coils aligned.  
         [0075]    FIGS.  20 A-B illustrate another configuration of the first magnetic plasma shaping apparatus  180 A. A plurality of upper and lower permanent magnets  216 A-B are disposed above, below, and along the width of the first lower end  124 B and have their longitudinal axis aligned generally orthogonal to the first plasma current path  160 . In one aspect, the plurality of first permanent magnets  216 A disposed above the first lower end  124 B have their magnetic poles aligned and are adjacent to and juxtaposed the plurality of second permanent magnets  216 B disposed below the first lower end  124 B. To form an opposing magnetic field, the magnetic poles of the first permanent magnets  216 A are aligned with the same magnetic poles of the second permanent magnets  216 B. For example, the north poles of the first permanent magnets  216 A are opposite the north poles of the second permanent magnets  216 B. Further, the magnetic north and south poles of adjacent discrete permanent magnets are aligned but opposite. For example, the magnetic north pole of a first discrete permanent magnet  216 A′ is aligned with the magnetic south pole of an adjacent second discrete permanent magnet  216 A″. Illustratively, the plurality of first permanent magnets  216 A provide an upper magnetic field  188 T disposed adjacent the toroidal path  160 . The plurality of second permanent magnets  214 B provide a lower magnetic field  188 U disposed adjacent the toroidal path  160  and adjacent the upper magnetic field  188 T. The upper and lower magnetic fields  188 T,  188 U define a magnetic opening  1891  disposed adjacent the lower end  124 B and generally orthogonal to the plasma current path  160 .  
         [0076]    FIGS.  21 A-B illustrates another configuration of the first magnetic plasma shaping apparatus  180 A. A plurality of first and second permanent magnets  218 A-E of varying dimensions are disposed above, below, and along the width of the first lower end  124 B and have their longitudinal axis aligned generally orthogonal to the first plasma current path  160 . In one aspect, the plurality of first permanent magnets  218 A-D disposed above the first lower end  124 B have their magnetic poles aligned and are adjacent to and juxtaposed the plurality of second permanent magnets  218 E disposed below the first lower end  124 B. To form an opposing magnetic field, the magnetic poles of the first permanent magnets  218 A-D are aligned with the same magnetic poles of the second permanent magnets  218 E. For example, the north poles of the first permanent magnets  218 A-D are opposite the north poles of the second permanent magnets  218 E. Further, the magnetic north and south poles of adjacent discrete permanent magnets are aligned. For example, the magnetic north pole of a first discrete permanent magnet  218 A is aligned with the magnetic north pole of an adjacent second discrete permanent magnet  218 B. Illustratively, the plurality of first permanent magnets  218 A-D provide an upper magnetic field  188 V disposed adjacent the toroidal path  1 - 60 . The plurality of second permanent magnets  218 B provide a lower magnetic field  188 W disposed adjacent the toroidal path  160  and adjacent the upper magnetic field  188 V. The upper and lower magnetic fields  188 V,  188 W define a magnetic opening  189 J disposed adjacent the lower end  124 B and generally orthogonal to the plasma current path  160 .  
         [0077]    FIGS.  12 A-B, through FIGS.  21 A-B, illustrate only a few of the plurality of magnetic element  184  configurations. For example, in one aspect the magnetic elements  184  may be a combination of both electromagnets and permanent magnets. In another aspect, the electromagnetic elements  184  may be formed into a single interchangeable apparatus. In still another aspect, the distance the electromagnetic elements  184  relative to the plasma may be adjusted to increase or decrease the magnetic field strength. In another aspect, the plurality of permanent magnets may be formed into a single magnet. While in one aspect the magnetic plasma shaping apparatuses  180 A-D may be used alone, it is contemplated that one or more of the magnetic plasma shaping apparatuses  180 A-D may be used in combination with the plasma shaping pairs  150 A-B,  151 A-B to define a desired plasma current profile.  
         [0078]    Operation  
         [0079]    During substrate processing, a gas is introduced into the hollow conduits  124 , 125  via gas inlets  111  and  123  respectively. The respective excitation sources  125  and  126  generate a current within the coil antennas  137 , 138 , to couple electromagnetic energy into the gas within each conduit  124 ,  125 , thereby striking plasma therein. A separate trigger circuit (not shown in illustrations) may also be used to facilitate plasma ignition. Plasma current and plasma then circulate though each toroidal plasma current path  160 - 161  through the respective plasma shaping apparatus pairs  150 A-B and  151 A-B and/or magnetic plasma shaping apparatuses  180 A-D to control the flow of current and density of plasma within the processing region  120 . The amount of power applied to the coil antennas  137 ,  138  also determines the amount of power coupled into the plasma between the substrate and showerhead  122 .  
         [0080]    During a deposition process, typically a non-silicon-containing gas such as nitrogen, hydrogen, oxygen, nitrous oxide, ammonia, any of the Group VIII noble gases including argon and helium, or like is flowed through each toroidal plasma current path  160 - 161  through gas inlets  111 ,  123 . Subsequently or simultaneaously, a silicon-containing gas such as Trimethylsilane (TMS), silane, TEOS, or the like is flowed from a gas inlet  117  into the showerhead  122  and then through the showerhead gas dispersion holes  121 . Some amount of non-silicon-containing gas may also be mixed with the silicon-containing gas and flowed through the showerhead  122 . The gas or the gas mixture entering through the showerhead  122  becomes the process gas and composes the portion of the toroidal plasma loop  160 ,  161  that is above a substrate placed on the substrate support member  130  to deposit a layer on the substrate surface. As the plasma is generated inductively and externally from the showerhead  122 , the amount of power used to dissociate the process gas is not applied with respect to the showerhead  122  and, more importantly, the substrate, which is atop the support member  130 . Thus, higher density plasma can thereby be achieved between the showerhead  122  and substrate without directly exposing the substrate to higher energy ion bombardment. This is an important consideration for film deposition applications which are sensitive to ion damage.  
         [0081]    During an etching process, typically a non-polymerizing etch gas such as chlorine, boron trichloride, hydrogen chloride, or the like or other gas such as oxygen, any of the Group VIII noble gases including argon and helium or the like is flowed through each toroidal path  160 - 161  through gas inlets  111 ,  123 , and the same gases or any other etch gas such as carbon tetrafluoride, carbon hexafluoride or like is flowed through the gas inlet  117  into the showerhead assembly  122  and then through the showerhead gas dispersion holes  121 . The etch gas dissociates in the plasma to produce an etching species between the showerhead  122  and a substrate placed on the substrate support member  130 . As the plasma is generated inductively and externally from the showerhead  122 , the amount of power used to dissociate the process gas is not applied with respect to the showerhead  122  and, more importantly, the substrate, which is atop the support member  130 . Thus, higher density plasma can thereby be achieved between the showerhead  122  and substrate without directly exposing the substrate to higher energy ion bombardment. This is an important consideration for film etching applications which are sensitive to ion damage.  
         [0082]    During a cleaning operation, a cleaning gas such as NF 3  is flowed from the gas inlet  117  into the showerhead  122  and then through the showerhead gas dispersion holes  121 . The cleaning gas or additional gas such as hydrogen, any of the Group VIII noble gases including argon and helium, or like may also be flowed to each toroidal plasma current path  160 , 161  through gas inlets  111 ,  123 . The cleaning gas dissociates in the plasma to produce a cleaning species within the processing region  120 . As the power to generate the cleaning species is applied external to the showerhead  122  and substrate support member  130 , these parts are protected from damage from ion bombardment from the cleaning species they would otherwise be exposed to if the showerhead  122  and substrate support member  130  were directly powered to generate the cleaning plasma. Furthermore, if the cleaning gas such as NF3 is distributed through the showerhead  122  and an inert gas is flowed through the hollow conduits  124 ,  125  , the conduit surfaces and the surfaces of the internal passageways of the showerhead  122  will not be exposed to attack from the cleaning gas ions and radicals, and the cleaning gas will not be needlessly “consumed” or neutralized by contact with surfaces that do not have deposits on them.  
         [0083]    In another embodiment, some processes may benefit from adding more RF power to the process plasma directly through the showerhead or by adding a RF bias to the substrate support member  130 . Whether the process is deposition, etching or cleaning, it is contemplated to apply additional power to the process plasma by driving the showerhead  122  and/or the substrate support member  130  with separate RF power supplies and matching networks.  
         [0084]    Although various embodiments which incorporate the teachings of the invention have been shown and described in detail herein, those skilled in the art can readily devise many other varied embodiments within the scope of the invention. For example, only one plasma-shaping apparatus of the first and second plasma-shaping apparatus pair  150 A-B,  151 A-B and/or magnetic plasma shaping apparatuses  180 A-D may be needed to achieve adequate plasma distribution. Furthermore, a plurality of conduits may be used to define multiple toroidal plasma current paths each having at least one plasma-shaping apparatus. Additionally, it is contemplated that only one plasma current path may be used for processing where one set of the plasma shaping apparatus pairs  150 A-B and/or magnetic plasma shaping apparatuses  180 A-D are adapted to seal one plasma current path. In another aspect, more than one plasma shaping apparatus pairs  150 A-B and/or magnetic plasma shaping apparatuses  180 A-D may be placed in-line to create different opening patterns. Further, the plasma shaping apparatuses  150 A-B,  151 A-B and/or magnetic plasma shaping apparatuses  180 A-D may be adjusted in-situ to alter the plasma distribution in the process region by making the entire plasma shaping apparatus or some elements of it movable.  
         [0085]    In another aspect, it is contemplated that the phase and power of each RF source  115 ,  127  may be adjusted independently to achieve the desired process plasma energy density distribution within the processing region  120 . By selecting various combinations of power and phase of the showerhead RF source  119 , the bias RF source  146 , and each inductive RF sources  115 ,  127 , the density of the plasma can be controlled over the larger rectangular substrates to overcome non-uniform deposition or etching and/or increase deposition or etch rates.  
         [0086]    In another aspect, the showerhead RF source  128  may be used to alter the plasma discharge within the processing region thereby affecting deposition or etching. For example, the RF source  128  may be increased in power to increase the power coupled to the plasma current path adjacent the showerhead  122 .  
         [0087]    In still another aspect, the RF source  146  is used to alter the deposition or etching process by adjusting the amount and/or energy with which ion species are attracted to the substrate surface. For example, the RF source  146  may be increased in power to increase the ion species attraction to the substrate support member  130 .  
         [0088]    While foregoing is directed to preferred embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.