Patent Publication Number: US-2022230852-A1

Title: Plasma processing apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is based on and claims priority to Japanese Priority Application No. 2021-008287 filed on Jan. 21, 2021, the entire contents of which are hereby incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present disclosure relates to a plasma processing apparatus. 
     2. Description of the Related Art 
     Japanese Laid-Open Patent Application Publication No. 2018-41685 discloses a plasma processing apparatus including an antenna device that includes an antenna including a plurality of antenna members extending along a predetermined track-like shape and having longitudinal coupling positions opposite to each other in a shorter direction so as to form a predetermined track-like shape having a longitudinal direction and a shorter direction. The antenna includes a deformable and electrically conductive coupling member connecting the ends of the adjacent plurality of antenna members, and at least two vertical moving mechanisms individually coupled to at least two of the plurality of antenna members and capable of raising and lowering at least two of the plurality of antenna members so as to change the bending angle of the coupling member as a fulcrum. 
     SUMMARY OF THE INVENTION 
     The present disclosure provides a plasma processing apparatus capable of regulating a supply of ions generated by plasma. 
     According to one embodiment of the present disclosure, there is provided a plasma processing apparatus including a process chamber. A turntable is disposed in the process chamber and is configured to receive a substrate along a circumferential direction thereof. A process gas supply nozzle is configured to supply a process gas to the turntable. A plasma antenna is disposed on the process chamber at a position covering at least a part of the process gas supply nozzle. An ion trap plate is disposed over the process gas supply nozzle at a position overlapping at least a part of the plasma antenna in the process chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a vertical schematic cross-sectional view illustrating a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 2  is a schematic plan view illustrating a configuration of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 3  is a cross-sectional view along a concentric circle of a susceptor of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 4  is an example of a longitudinal sectional view of a plasma generator of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 5  is an exploded perspective view of an example of a plasma generator of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 6  is a perspective view of an example of a housing disposed in a plasma generator of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 7  is a vertical cross-sectional view of a plasma processing apparatus cut through a vacuum chamber along a rotational direction of a susceptor according to an embodiment of the present disclosure; 
         FIG. 8  is a perspective view illustrating an enlarged view of a gas nozzle for plasma processing disposed in a plasma processing region of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 9  is a plan view of an example of a plasma generator of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 10  is a perspective view illustrating a part of a Faraday shield disposed in a plasma generator of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 11  is a perspective view of a plasma processing apparatus according to embodiments of the present disclosure; 
         FIG. 12  is a side view of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 13  is a side view of an antenna of a plasma processing apparatus according to an embodiment of the present disclosure; 
         FIG. 14  is a diagram illustrating an example of a plasma processing apparatus including an ion trap plate according to an embodiment of the present disclosure; 
         FIG. 15  is a diagram illustrating an example of an ion trap plate; 
         FIG. 16  is a diagram illustrating an example of a movable ion trap plate; and 
         FIGS. 17A and 17B  are diagrams illustrating an arrangement example of an ion trap plate in a vacuum chamber. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. 
     [Configuration of Plasma Processing Apparatus] 
       FIG. 1  is a schematic vertical cross-sectional view illustrating an example of a plasma processing apparatus according to an embodiment of the present invention.  FIG. 2  is a schematic plan view illustrating an example of the plasma processing apparatus according to the embodiment. In  FIG. 2 , for convenience of explanation, a depiction of a top plate  11  is omitted. 
     As illustrated in  FIG. 1 , the plasma processing apparatus of the embodiment includes a vacuum chamber  1  having a substantially circular planar shape, and a susceptor  2  that is disposed in the vacuum chamber  1  such that the rotational center of the susceptor  2  coincides with the center of the vacuum chamber  1 . The susceptor  2  rotates wafers W placed thereon by rotating around its rotational center. 
     The vacuum chamber  1  is a process chamber to accommodate wafers W therein and to perform a plasma process on a film or the like deposited on surfaces of the wafers W. The vacuum chamber  1  includes a top plate (ceiling)  11  that faces recesses  24  formed in a surface of the susceptor  2 , and a chamber body  12 . A ring-shaped seal member  13  is provided at the periphery of the upper surface of the chamber body  12 . The top plate  11  is configured to be attachable to and detachable from the chamber body  12 . The diameter (inside diameter) of the vacuum chamber  1  in plan view is, for example, about 1100 mm, but is not limited to this. 
     A separation gas supply pipe  51  is connected to the center of the upper side of the vacuum chamber  1  (or the center of the top plate  11 ). The separation gas supply pipe  51  supplies a separation gas to a central area C in the vacuum chamber  1  to prevent different process gases from mixing with each other in the central area C. 
     A central part of the susceptor  2  is fixed to an approximately-cylindrical core portion  21 . A rotational shaft  22  is connected to a lower surface of the core portion  21  and extends in the vertical direction. The susceptor  2  is configured to be rotatable by a drive unit  23  about the vertical axis of the rotational shaft  22 , in a clockwise fashion in the example of  FIG. 2 . The diameter of the susceptor  2  is, for example, but is not limited to, about 1000 mm. 
     The rotational shaft  22  and the drive unit  23  are housed in a case body  20 . An upper-side flange of the case body  20  is hermetically attached to the lower surface of a bottom part  14  of the vacuum chamber  1 . A purge gas supply pipe  72  is connected to the case body  20 . The purge gas supply pipe  72  supplies a purge gas (separation gas) such as argon gas to an area below the susceptor  2 . 
     A part of the bottom part  14  of the vacuum chamber  1  surrounding the core portion  21  forms a ring-shaped protrusion  12   a  that protrudes so as to approach the susceptor  2  from below. 
     Circular recesses  24  (or substrate receiving areas), where the wafers W having a diameter of, for example, 300 mm are placed, are formed in the upper surface of the susceptor  2 . A plurality of (e.g., five) recesses  24  are provided along the rotational direction of the susceptor  2 . Each of the recesses  24  has an inner diameter that is slightly (e.g., from 1 mm to 4 mm) greater than the diameter of the wafer W. The depth of the recess  24  is substantially the same as or greater than the thickness of the wafer W. Accordingly, when the wafer W is placed in the recess  24 , the height of the upper surface of the wafer W becomes substantially the same as or lower than the height of the upper surface of the susceptor  2  where the wafers W are not placed. When the depth of the recess  24  is excessively greater than the thickness of the wafer W, it may adversely affect film deposition. Therefore, the depth of the recess  24  is preferably less than or equal to about three times the thickness of the wafer W. Through holes (not illustrated in the drawings) are formed in the bottom of the recess  24  to allow a plurality of (e.g., three) lifting pins (which are described later) to pass through. The lifting pins raise and lower the wafer W. 
     As illustrated in  FIG. 2 , a first process area P 1 , a second process area P 2  and a third process area P 3  are provided apart from each other along the rotational direction of the susceptor  2 . Because the third process area P 3  is a plasma processing area, it may be also referred to as a plasma processing area P 3  hereinafter. A plurality of (e.g., seven) gas nozzles  31 ,  32 ,  33 ,  34 ,  35 ,  41 , and  42  made of, for example, quartz are arranged at intervals in a circumferential direction of the vacuum chamber  1 . The gas nozzles  31  through  35 ,  41 , and  42  extend radially, and are disposed to face areas that the recesses  24  of the susceptor  2  pass through. The nozzles  31  through  35 ,  41 , and  42  are placed between the susceptor  2  and the top plate  11 . Here, each of the gas nozzles  31  through  35 ,  41 , and  42  extends horizontally from the outer wall of the vacuum chamber  1  toward the central area C so as to face the wafers W. On the other hand, the gas nozzle  35  extends from the outer wall of the vacuum chamber  1  toward the central area C, and then bends and extends linearly along the central area C in a counterclockwise fashion (opposite direction of the rotational direction of the susceptor  2 ). In the example of  FIG. 2 , plasma processing gas nozzles  33  and  34 , a plasma processing gas nozzle  35 , a separation gas nozzle  41 , a first process gas nozzle  31 , a separation gas nozzle  42  and a second process gas nozzle  32  are arranged in a clockwise fashion (the rotational direction of the susceptor  2 ) from a transfer opening  15  in this order. Here, a gas supplied from the second process gas nozzle  32  is often similar to a gas supplied from the plasma processing gas nozzles  33  through  35 , but the second process gas nozzle  32  may not be necessarily provided when the plasma processing gas nozzles  33  through  35  sufficiently supply the gas. 
     Also, the plasma processing gas nozzles  33  to  35  may be substituted with a single plasma processing gas nozzle. In this case, for example, a plasma processing gas nozzle extending from the outer peripheral wall of the vacuum chamber  1  toward the central region C may be disposed, similar to the second process gas nozzle  32 . 
     The first process gas nozzle  31  forms a “first process gas supply part”. Each of the plasma processing gas nozzles  33 ,  34  and  35  forms a “plasma processing gas supply part”. Each of the separation gas nozzles  41  and  42  forms a “separation gas supply part”. 
     Each of the gas nozzles  31  through  35 ,  41 , and  42  is connected to gas supply sources (not illustrated in the drawings) via a flow control valve. 
     Gas discharge holes  36  for discharging a gas are formed in the lower side (which faces the susceptor  2 ) of each of the nozzles  31  through  35 ,  41 , and  42 . The gas discharge holes  36  are formed, for example, at regular intervals along the radial direction of the susceptor  2 . The distance between the lower end of each of the nozzles  31  through  35 ,  41 , and  42  and the upper surface of the susceptor  2  is, for example, from about 1 mm to about 5 mm. 
     An area below the first process gas nozzle  31  is a first process area P 1  where a first process gas is adsorbed on the wafer W. An area below the second process gas nozzle  32  is a second process area P 2  where a second process gas that can produce a reaction product by reacting with the first process gas is supplied to the wafer W. An area below the plasma processing gas nozzles  33  through  35  is a third process area P 3  where a modification process is performed on a film on the wafer W. The separation gas nozzles  41  and  42  are provided to form separation areas D for separating the first process area P 1  from the second process area P 2 , and separating the third process area P 3  from the first process area P 1 , respectively. Here, the separation area D is not provided between the second process area P 2  and the third process area P 3 . This is because the second process gas supplied in the second process area P 2  and the mixed gas supplied in the third process area P 3  partially contain a common component therein in many cases, and therefore the second process area P 2  and the third process area P 3  do not have to be separated from each other by particularly using the separation gas. 
     Although described in detail later, the first process gas nozzle  31  supplies a source gas that forms a principal component of a film to be deposited. For example, when the film to be deposited is a silicon oxide film (SiO 2 ), the first process gas nozzle  31  supplies a silicon-containing gas such as an organic aminosilane gas. The second process gas nozzle  32  supplies an oxidation gas such as oxygen gas and ozone gas. The plasma processing gas nozzles  33  through  35  supply a mixed gas containing the same gas as the second process gas and a noble gas to perform a modification process on the deposited film. For example, when the film to be deposited is the silicon oxide film (SiO 2 ), the plasma processing gas nozzles  33  through  35  supply a mixed gas of the oxidation gas such as oxygen gas and ozone gas same as the second process gas and a noble gas such as argon and helium. Because the plasma processing gas nozzles  33  to  35  are configured to supply gases to different regions on the susceptor  2 , the flow ratio of the noble gas may vary from region to region, and the modification process may be performed uniformly. 
       FIG. 3  illustrates a cross section of a part of the substrate processing apparatus taken along a concentric circle of the susceptor  2 . More specifically,  FIG. 3  illustrates a cross section of a part of the substrate processing apparatus from one of the separation areas D through the first process area P 1  to the other one of the separation areas D. 
     Approximately fan-like convex portions  4  are provided on the lower surface of the top plate  11  of the vacuum chamber  1  at locations corresponding to the separation areas D. The convex portions  4  are attached to the back surface of the top plate  11 . In the vacuum chamber  1 , flat and low ceiling surfaces  44  (first ceiling surfaces) are formed by the lower surfaces of the convex portions  4 , and ceiling surfaces  45  (second ceiling surfaces) are formed by the lower surface of the top plate  11 . The ceiling surfaces  45  are located on both sides of the ceiling surfaces  44  in the circumferential direction, and are located higher than the ceiling surfaces  44 . 
     As illustrated in  FIG. 2 , each of the convex portions  4  forming the ceiling surface  44  has a fan-like planar shape whose apex is cut off to form an arc-shaped side. Also, a groove  43  extending in the radial direction is formed in each of the convex portions  4  at the center in the circumferential direction. Each of the separation gas nozzles  41  and  42  is placed in the groove  43 . A peripheral part of the convex portion  4  (a part along the outer edge of the vacuum chamber  1 ) is bent to form an L-shape to prevent the process gases from mixing with each other. The L-shaped part of the convex portion  4  faces the outer end surface of the susceptor  2  and is slightly apart from the chamber body  12 . 
     A nozzle cover  230  is provided above the first process gas nozzle  31 . The nozzle cover  230  causes the first process gas to flow along the wafer W, and causes the separation gas to flow near the top plate  11  instead of near the wafer W. As illustrated in  FIG. 3 , the nozzle cover  230  includes an approximately-box-shaped cover body  231  having an opening in the lower side to accommodate the first process gas nozzle  31 , and current plates  232  connected to the upstream and downstream edges of the opening of the cover body  231  in the rotational direction of the susceptor  2 . A side wall of the cover body  231  near the rotational center of the susceptor  2  extends toward the susceptor  2  to face a tip of the first process gas nozzle  31 . Another side wall of the cover body  231  near the outer edge of the susceptor  2  is partially cut off so as not to interfere with the first process gas nozzle  31 . 
     As illustrated in  FIG. 2 , a plasma generating device  80  is provided above the plasma processing gas nozzles  33  through  35  to convert a plasma processing gas discharged into the vacuum chamber  1  to plasma. 
       FIG. 4  is a vertical cross-sectional view of an example of the plasma generating device  80 .  FIG. 5  is an exploded perspective view of an example of the plasma generating device  80 .  FIG. 6  is a perspective view of an example of a housing  90  of the plasma generating device  80 . 
     The plasma generating device  80  is configured by winding an antenna  83  made of a metal wire or the like, for example, three times around a vertical axis in a coil form. In plan view, the plasma generating device  80  is disposed to surround a strip-shaped area extending in the radial direction of the susceptor  2  and to extend across the diameter of the wafer W on the susceptor  2 . 
     The antenna  83  is connected through a matching box  84  to a high frequency power source  85  that has, for example, a frequency of 13.56 MHz and output power of 5000 W. The antenna  83  is hermetically separated from the inner area of the vacuum chamber  1 . As illustrated in  FIGS. 1, 2, and 4 , a connection electrode  86  electrically connects the antenna  83 , the matching box  84 , and the high frequency power source  85 . 
     The antenna  83  has a foldable configuration at the top and the bottom, and has a lifting mechanism enabling the antenna  83  to be folded automatically at the top and the bottom. However, in  FIG. 2 , details thereof are omitted. The details are described later. 
     As illustrated in  FIGS. 4 and 5 , an opening  11   a  having an approximately fan-like shape in plan view is formed in the top plate  11  above the plasma processing gas nozzles  33  through  35 . 
     An ion trap plate is disposed over the plasma processing gas nozzles  33  to  35 . The ion trap plate  140  is a shield plate for limiting the supply of generated plasma ions to the wafer W and for improving uniformity of plasma processing across a surface of the wafer W. Details of the ion trap plate  130  will be described later. First, components other than the ion trap plate  140 , which are necessary for the plasma processing apparatus, will be mainly described. 
     As illustrated in  FIG. 4 , a ring-shaped member  82  is hermetically attached to the periphery of the opening  11   a . The ring-shaped member  82  extends along the periphery of the opening  11   a . The housing  90  is hermetically attached to the inner circumferential surface of the ring-shaped member  82 . That is, the outer circumferential surface of the ring-shaped member  82  faces an inner surface  11   b  of the opening  11   a  of the top plate  11 , and the inner circumferential surface of the ring-shaped member  82  faces a flange part  90   a  of the housing  90 . The housing  90  is placed via the ring-shaped member  82  in the opening  11   a  to enable the antenna  83  to be placed at a position lower than the top plate  11 . The housing  90  may be made of a dielectric material such as quartz. The bottom surface of the housing  90  forms a ceiling surface  46  of the plasma processing area P 3 . 
     As illustrated in  FIG. 6 , an upper peripheral part surrounding the entire circumference of the housing  90  extends horizontally to form the flange part  90   a . Moreover, a central part of the housing  90  in plan view is recessed toward the inner area of the vacuum chamber  1 . 
     The housing  90  is arranged so as to extend across the diameter of the wafer W in the radial direction of the susceptor  2  when the wafer W is located under the housing  90 . A seal member  11   c  such as an O-ring is provided between the ring-shaped member  82  and the top plate  11 . 
     The internal atmosphere of the vacuum chamber  1  is hermetically sealed by the ring-shaped member  82  and the housing  90 . As illustrated in  FIG. 5 , the ring-shaped member  82  and the housing  90  are placed in the opening  11   a , and the entire circumference of the housing  90  is pressed downward via a frame-shaped pressing member  91  that is placed on the upper surfaces of the ring-shaped member  82  and the housing  90  and extends along a contact region between the ring-shaped member  82  and the housing  90 . The pressing member  91  is fixed to the top plate  11  with, for example, bolts (not illustrated in the drawing). As a result, the internal atmosphere of the vacuum chamber  1  is sealed hermetically. In  FIG. 5 , a depiction of the ring-shaped member  82  is omitted for simplification. 
     As illustrated in  FIG. 6 , the housing  90  also includes a protrusion  92  that extends along the circumference of the housing  90  and protrudes vertically from the lower surface of the housing  90  toward the susceptor  2 . The protrusion  92  surrounds the second process area P 2  below the housing  90 . The plasma processing gas nozzles  33  through  35  are accommodated in an area surrounded by the inner circumferential surface of the protrusion  92 , the lower surface of the housing  90 , and the upper surface of the susceptor  2 . A part of the protrusion  92  near a base end (at the inner wall of the vacuum chamber  1 ) of each of the plasma processing gas nozzles  33  through  35  is cut off to form an arc-shaped cut-out that conforms to the outer shape of each of the plasma processing gas nozzles  33  through  35 . 
     As illustrated in  FIG. 4 , on the lower side (i.e., the second process area P 2 ) of the housing  90 , the protrusion  92  is formed along the circumference of the housing  90 . The protrusion  92  prevents the seal member  11   c  from being directly exposed to plasma, i.e., isolates the seal member  11   c  from the second process area P 2 . This causes plasma to pass through an area under the protrusion  92  even when plasma spreads from the second process area P 2  toward the seal member  11   c , thereby deactivating the plasma before reaching the seal member  11   c.    
     Moreover, as illustrated in  FIG. 4 , the plasma processing gas nozzles  33  through  35  are provided in the third process area P 3  under the housing  90 , and are connected to an argon gas supply source  120 , a helium gas supply source  121  and an oxygen gas supply source  122 , respectively. Furthermore, corresponding flow controllers  130 ,  131  and  132  are provided between the plasma processing gas nozzles  33  through  35  and the argon gas supply source  120 , the helium gas supply source  121  and the oxygen gas supply source  122 , respectively. Ar gas, He gas and O 2  gas are supplied from the argon gas supply source  120 , the helium gas supply source  121  and the oxygen gas supply source  122  to each of the plasma processing gas nozzles  33  through  35  at predetermined flow rates (mixing ratios, mix proportions) through each of the flow controllers  130 ,  131  and  132 , and flow rates thereof are determined depending on supplied areas. 
     When a single plasma processing gas nozzle is used, for example, the mixture of the above-described Ar gas, He gas, and O 2  gas is supplied to the single plasma processing gas nozzle. 
       FIG. 7  is a vertical cross-sectional view of the vacuum chamber  1  taken along the rotational direction of the susceptor  2 . As illustrated in  FIG. 7 , because the susceptor  2  rotates in a clockwise fashion during the plasma process, Ar gas is likely to intrude into an area under the housing  90  from a clearance between the susceptor  2  and the protrusion  92  by being brought by the rotation of the susceptor  2 . To prevent Ar gas from intruding into the area under the housing  90  through the clearance, a gas is discharged to the clearance from the area under the housing  90 . More specifically, as illustrated in  FIGS. 4 and 7 , the gas discharge holes  36  of the plasma processing gas nozzle  34  are arranged to face the clearance, that is, to face the upstream side in the rotational direction of the susceptor  2  and downward. A facing angle θ of the gas discharge holes  36  of the plasma processing gas nozzle  33  relative to the vertical axis may be, for example, about 45 degrees as illustrated in  FIG. 7 , or may be about 90 degrees so as to face the inner side wall of the protrusion  92 . In other words, the facing angle θ of the gas discharge holes  36  may be set at an appropriate angle capable of properly preventing the intrusion of Ar gas in a range from 45 to 90 degrees depending on the intended use. 
       FIG. 8  is an enlarged perspective view illustrating the plasma processing gas nozzles  33  through  35  provided in the plasma processing area P 3 . As illustrated in  FIG. 8 , the plasma processing gas nozzle  33  is a nozzle capable of covering the whole of the recess  24  in which the wafer W is placed, and supplying a plasma processing gas to the entire surface of the wafer W. On the other hand, the plasma processing gas nozzle  34  is a nozzle provided slightly above the plasma processing gas nozzle  33  so as to approximately overlap the plasma processing gas nozzle  33 . The length of the plasma processing gas nozzle  34  is about half the length of the plasma processing gas nozzle  33 . The plasma processing gas nozzle  35  extends from the outer peripheral wall of the vacuum chamber  1  along the radius of the downstream side of the fan-like plasma process area P 3  in the rotational direction of the susceptor  2 , and has a shape bent linearly along the central area C after reaching the neighborhood of the central area C. Hereinafter, for convenience of distinction, the plasma processing gas nozzle  33  covering the whole area may be referred to as a base nozzle  33 , and the plasma processing gas nozzle  34  covering only the outer area may be referred to as an outer nozzle  34 . Also, the plasma processing gas nozzle  35  extending to the inside may be referred to as an axis-side nozzle  35 . 
     The base nozzle  33  is a gas nozzle for supplying a plasma processing gas to the whole surface of the wafer W. As illustrated in  FIG. 7 , the base gas nozzle  33  discharges the plasma processing gas toward the protrusion  92  forming the side surface separating the plasma process area P 3  from the other area. 
     On the other hand, the outer nozzle  34  is a nozzle for supplying a plasma processing gas selectively to an outer area of the wafer W. The plasma processing gas supplied to the plasma process area P 3  is converted to plasma by passing through the highest part of the plasma process area P 3 , which is also close to the plasma generating device  80 . More specifically, because the plasma generating device  80  is provided above the plasma processing area P 3 , the plasma processing gas flowing along the ceiling surface  46  (see  FIG. 7 ) of the plasma processing area P 3  is converted to plasma, which contributes to the plasma process. In other words, the neighborhood of the ceiling surface  46  of the plasma processing area P 3  forms a plasma generation area, and the plasma processing gas having passed the plasma generation area is properly converted to the plasma. The outer nozzle  34  performs a process for increasing a flow rate of a plasma processing gas supplied from the outer nozzle  34  and a flow speed of the plasma processing gas of the outer area when an amount of plasma process performed on a film deposited on the wafer W after the plasma process is obtained and the result of the amount of plasma process is insufficient in the outer area. As the flow speed of the plasma processing gas increases, the amount of plasma processing gas converted to the plasma per unit time increases, which accelerates the plasma process. Accordingly, based on this perspective, the gas discharge holes  36  (not illustrated in the drawings) of the outer nozzle  34  are provided to face upward and the ceiling surface  46  of the plasma processing area P 3 , and are configured to lead the supplied plasma processing gas to the ceiling surface  46  of the plasma process area P 2 . 
     The axis-side nozzle  35  is a nozzle for supplying a plasma processing gas selectively to an area near the axis of the susceptor  2  of the wafer W. Hence, the gas discharge holes  36  (not illustrated in the drawings) are formed only in a part of the tip of the axis-side nozzle  35  extending along the central area C, and are configured to supply the plasma processing gas to the area of the wafer W near the axis of the susceptor  2 . In the axis-side nozzle  35 , the gas discharge holes  36  also face upward and are provided at a location facing the ceiling surface  46  of the plasma processing area P 3 . This causes the plasma processing gas supplied from the axis-side nozzle  35  to immediately flow toward the plasma generation area and to be converted to plasma efficiently. In the event that an insufficient plasma process on the wafer W in the area near the axis of the susceptor  2  is found when obtaining a processing distribution within a surface of a film on the wafer W after the plasma process, a process for increasing a flow rate and thereby increasing a flow speed of the plasma processing gas supplied from the axis-side nozzle  35  is performed. Because the amount of plasma converted from the plasma processing gas per unit time increases as the flow rate of the plasma processing gas increases, the plasma process is accelerated. In view of this, the gas discharge holes  36  of the outer nozzle  34  (not illustrated in the drawing) are provided to face upward so as to face the ceiling surface  46  of the plasma processing area P 3 , and are configured to cause the plasma processing gas to flow toward the ceiling surface  46  of the plasma processing area P 3 . 
     The axis-side nozzle  35  is a nozzle to mainly supply the plasma processing gas to the central area near the axial side of the susceptor  2  on the wafer W. Hence, the gas discharge holes  36  (not illustrated in the drawing) are formed only in a portion of the tip the axis-side nozzle  35  along the central area C, and are configured to supply the plasma processing gas to the area on the central side of the wafer W. Even in the axis-nozzle  35 , the gas discharge holes  36  face upward and provided in a position opposite to the ceiling surface  456  of the plasma processing area P 3 . Thus, the plasma processing gas supplied from the axis-side nozzle  35  immediately goes toward the plasma generation area and is efficiently converted to plasma. 
     In this manner, by providing the outer nozzle  34  and the axis-side nozzle  35  in addition to the base nozzle  33 , the flow ratio (mixing ratio, or mix proportion) of the noble gas and the reaction gas contained in the mixed gas can be adjusted for each area, thereby adjusting the quantity of processing across the surface of the film on the wafer W. 
     The adjustment of the quantity of processing across the surface of the wafer W is generally performed to improve the uniformity of the plasma process across the surface of the wafer W, but when making a difference of the amount of plasma process for each area is desired, a flow ratio of helium gas contained in the plasma processing gas supplied from the nozzles  33  through  35  to the area desired to increase the quantity of processing just has to be increased, and the mixing ratio (mix proportion) of helium gas just has to be increased. Accordingly, in addition to the improvement of the process uniformity across the surface of the wafer W, a variety of adjustments of the quantity of processing is possible. 
     In this manner, by providing the plasma processing gas nozzles  34  and  35  for flow rate adjustment for each area, the adjustment of the amount of plasma process across the surface can be performed readily and accurately. In  FIG. 8 , although an example of including three of the plasma processing gas nozzles  33  through  35  is illustrated, the adjustment of the quantity of processing across the surface may be performed more finely and accurately by installing more plasma processing gas nozzles. The number, a shape, an installation location and the like of the plasma processing gas nozzles  33  through  35  can be changed depending on the intended use. 
     Next, a detailed description is given below of a Faraday shield  95  of the plasma generating device  80 . As illustrated in  FIGS. 4 and 5 , a Faraday shield  95  is provided on the upper side of the housing  90 . The Faraday shield  95  is grounded, and is composed of a conductive plate-like part such as a metal plate (e.g., copper plate) that is shaped to roughly conform to the internal shape of the housing  90 . The Faraday shield  95  includes a horizontal surface  95   a  that extends horizontally along the bottom surface of the housing  90 , and a vertical surface  95   b  that extends upward from the outer edge of the horizontal surface  95   a  and surrounds the horizontal surface  95   a . The Faraday shield  95  may be configured to be, for example, a substantially hexagonal shape in a plan view. 
       FIG. 9  is a plan view of an example of the plasma generating device  80 .  FIG. 10  is a perspective view of a part of the Faraday shield  95  provided in the plasma generating device  80 . 
     When seen from the rotational center of the susceptor  2 , the right and left upper ends of the Faraday shield  95  extend horizontally rightward and leftward, respectively, to form supports  96 . A frame  99  is provided between the Faraday shield  95  and the housing  90  to support the supports  96  from below. The frame  99  is supported by a part of the housing  90  near the central area C and a part of the flange part  90   a  near the outer edge of the susceptor  2 . 
     When an electric field reaches the wafer W, for example, electric wiring and the like formed inside the wafer W may be electrically damaged. To prevent this problem, as illustrated in  FIG. 10 , a plurality of slits  97  is formed in the horizontal surface  95   a . The slits  97  prevent an electric-field component of an electric field and a magnetic field (electromagnetic field) generated by the antenna  83  from reaching the wafer W below the Faraday shield  95 , and allow a magnetic field component of the electromagnetic field to reach the wafer W. 
     As illustrated in  FIGS. 9 and 10 , the slits  97  extend in directions that are orthogonal to the direction in which the antenna  83  is wound, and are arranged to form a circle below the antenna  83 . The width of each slit  97  is set at a value that is about 1/10000 or less of the wavelength of a high frequency supplied to the antenna  83 . Circular electrically-conducting paths  97   a  made of, for example, a grounded conductor are provided at the ends in the length direction of the slits  97  to close the open ends of the slits  97 . An opening  98  is formed in an area of the Faraday shield  95  where the slits  97  are not formed, i.e., an area surrounded by the antenna  83 . The opening  98  is used to check whether plasma is emitting light. In  FIG. 2 , the slits  97  are omitted for simplification, but an area where the slits  97  are formed is indicated by a dashed-dotted line. 
     As illustrated in  FIG. 5 , an insulating plate  94  is stacked on the horizontal surface  95   a  of the Faraday shield  95 . The insulating plate  94  is made of, for example, quartz having a thickness of about 2 mm, and is used for insulation between the Faraday shield  95  and the plasma generating device  80  disposed over the Faraday shield  95 . Thus, the plasma generating device  80  is arranged to cover the inside of the vacuum chamber  1  (i.e., the wafer W on the susceptor  2 ) through the housing  90 , the Faraday shield  95 , and the insulating plate  94 . 
     Next, an example of an antenna device  81  for holding an antenna according to an embodiment of the present disclosure and a plasma generating device  80  will be described. 
       FIG. 11  is a perspective view of an antenna device  81  and a plasma generating device  80 .  FIG. 12  is a side view of an antenna device  81  and a plasma generating device  80 . 
     The antenna device  81  includes an antenna  83 , a connection electrode  86 , a lifting mechanism  87 , a linear encoder  88 , and a fulcrum jig  89 . 
     Also, the plasma generating device  80  further includes the antenna device  81 , a matching box  84 , and a radio frequency power source  85 . 
     The antenna  83  includes an antenna member  830 , a coupling member  831  and a spacer  832 . The antenna  83  is generally configured in a coil shape, or a track-like shape, and is planar in an elongate annular shape having a longitudinal direction and a shorter direction (or a width direction). The planar shape may be an ellipse having an angle or a shape close to a rectangular frame having an angle. Such a track-like shape of antenna  83  is formed by coupling the antenna members  830 . The antenna member  830  is part of the antenna  83  and is formed by connecting ends of a plurality of small antenna members  830  extending along the track-like shape. The antenna member  830  includes a straight portion  8301  having a straight shape and curved portion  8302  having a curved shape for bending and connecting the straight portions  8301 . 
     Then, by combining and connecting the straight portions  8301  and the curved portions  8302 , the antenna members  830  are connected to antenna members  830   a  and  830   b  at both ends and the antenna members  830   c  and  830   d  at central portions to form a track-like shape as a whole. In  FIG. 11 , the antenna  83  has, as an overall shape, the antenna members  830   a  and  830   b  at both ends having a shape close to an arc, and the antenna members  830   c  and  830   d  at the central portions having a linear shape. The antenna members  830   a  and  830   b  at the ends of the antenna members  830   c  and  830   d  in the shape close to the arc are connected to each other with the antenna members  830   c  and  830   d  in the central linear shape, and the central antenna members  830   c  and  830   d  are substantially parallel to each other. The antenna  83  is generally shaped such that the antenna members  830   c  and  830   d  have a long side and the antenna members  830   a  and  830   b  have a short side. 
     As illustrated in  FIG. 11 , the antenna members  830   a  and  830   b  are formed in a shape that approximates an arc shape where three straight portions  8301  are connected via two curved portions  8302 . The antenna member  830   c  is composed of one long straight portion  8301 . As illustrated in  FIGS. 11 and 12 , the antenna member  830   d  is formed by forming two long straight portions  8301  and one short straight portion between them with steps at the top and the bottom, so that two small curved portions  8302  are formed by being coupled to each other. 
     The antenna member  830  forms a multi-stage track-like shape as a whole, and in  FIGS. 11 and 12 , an antenna member  830  is illustrated forming a three-stage track-like shape. 
     The coupling member  831  is a member for connecting adjacent antenna members  830  to each other and is made with a material that is conductive and can be deformed. The coupling member  831  may be made with, for example, a flexible substrate or the like, and may be made with a copper material. The copper material is a highly conductive and a soft material, and is suitable for coupling the antenna members  830  to each other. 
     Because the coupling members  831  are made with a flexible material, it is possible to bend the antenna members  830  with the coupling members  831  as a fulcrum. This allows the antenna members  830  to be maintained in a bent state at the point of the coupling members  831 , while allowing the configuration of the antenna  83  to be varied. The distance between the antenna  83  and the wafer W is likely to affect the intensity of the plasma process. When the antenna  83  is brought close to the wafer W, the intensity of the plasma process is likely to increase, and when the antenna  83  is removed from the wafer W, the intensity of the plasma process is likely to decrease. 
     Further, the method of determining the shape of the antenna  83  and the details of the shape will be described below. 
     When the wafer W is loaded on the recess  24  of the susceptor  2  and the susceptor  2  is rotated to perform the plasma process, the wafer W is positioned along the circumferential direction of the susceptor  2 , and the moving speed of the center side of the susceptor  2  is low and the moving speed of the outer side is high. Thus, the intensity (or processing amount) of the plasma process at the center of the wafer W, which is irradiated with plasma for a long time, is likely to be higher than the intensity of the plasma process at the outer periphery. To correct this, for example, if the antenna member  830   a  disposed on the central side is folded upwardly and the antenna member  830   b  disposed on the peripheral side is folded downwardly, the central plasma processing intensity is reduced; the peripheral plasma processing intensity is increased, and the overall plasma processing amount is uniform in the radial direction of the susceptor  2 . 
     In  FIG. 11 , four coupling members  831  are provided for connecting four antenna members  830   a  to  830   d  to each other. However, the number of antenna members  830  and connecting members  831  may be increased or decreased depending on the application. At a minimum, the antenna members  830   a  and  830   b  at both ends may be present, which may be configured in a long U-shaped shape extending not only at both ends but also to the central portion, and the two antenna members  830   a  and the antenna members  830   b  are connected by the two coupling members  831 . Further, if the shape of the antenna  83  is desired to be varied more widely, four antenna members  830  may be disposed at the center to increase the bendable portion. 
     In any case, facing coupling members  831  are preferably disposed at the same position in the longitudinal direction, that is, equal in length in the longitudinal direction of the facing antenna members  830 . As noted above, the antenna  83  is preferably configured to change its height in the longitudinal direction, while using the bending points facing each other in the shorter direction and coinciding with each other in the longitudinal direction. In this embodiment, the coupling members  831  coupling the antenna member  830   a  to the antenna member  830   c  and the coupling members  831  coupling the antenna member  830   a  to the antenna member  830   d  are configured to face each other in the shorter direction and be in the same position in the longitudinal direction. Similarly, the coupling member  831 , which couples the antenna member  830   b  to the antenna member  830   c , and the coupling member  831 , which couples the antenna member  830   b  to the antenna member  830   d , are also configured to face each other in the shorter direction and be in the same position in the longitudinal direction. Such an arrangement allows the shape of the antenna  83  to be varied to adjust the intensity of the plasma process in the longitudinal direction. 
     However, when the bending portion is shifted in an oblique direction and a deformation such as a parallel quadrant is desired, it is possible to set the longitudinal positions of the coupling member  831  to different positions on the  830   c  side and the  830   d  side in the oblique direction instead of facing each other in the shorter direction. 
     A spacer  832  is a member for separating multi-stage antenna members  830  disposed at an upper stage and a lower stage from each other so that even if antenna  83  is deformed, the antenna members  830  do not contact the upper and lower stages and do not cause a short circuit. 
     The lifting mechanism  87  is a vertical motion mechanism for moving the antenna member  830  up and down. The lifting mechanism  87  includes an antenna retainer  870 , a drive unit  871 , and a frame  872 . The antenna retainer  870  is the retaining portion of the antenna  83  and the drive unit  871  is a driving part for moving the antenna  83  up and down through the antenna retainer  870 . The antenna retainer  870  may have various configurations if it can hold the antenna member  830  of the antenna  83 , but may be constructed to hold the antenna member  830  around the perimeter of the antenna member  830 , for example, as illustrated in  FIG. 12 . 
     The drive unit  871  may also use various drivers if the antenna members  830  can be moved up and down, for example, an air cylinder for air drive may be used. In  FIG. 12 , an example is illustrated in which an air cylinder is applied to the drive unit  871  of the lifting mechanism  87 . In addition, a motor or the like may be used for the lofting mechanism  87 . 
     A frame  872  is a support for holding the drive unit  871 , and holds the drive unit  871  at an appropriate position. The antenna retainer  870  is retained by the drive unit  871 . 
     The lifting mechanism  87  is disposed for at least two or more of the antenna members  830   a  to  830   d  individually. In this embodiment, deformation of the antenna  83  is performed automatically using the lifting mechanism  87 , rather than being adjusted by the operator. Thus, to deform the antenna  83  into various shapes, preferably, each of the antenna members  830   a  to  830   d  individually includes the lifting mechanism  87 , each of which operates independently. Thus, the lifting mechanism  87  is preferably disposed for each of the antenna members  830   a  to  830   d , and the lifting mechanism  87  is disposed for at least two of the antenna members  830   a  to  830   d  even when the lifting mechanism  87  is not disposed for each of the antenna members  830   a  to  830   d.    
     In  FIGS. 11 and 12 , only a single lifting mechanism  87  is shown, but actually, the lifting mechanism  87  is disposed for each of the antenna members  830   a  to  830   d  to be bent. For example, if a lifting mechanism  87  for moving the antenna member  830   a  up and down is disposed at the center of the rotational direction of the susceptor  2  and a lifting mechanism  87  for moving the antenna members  830   c  and  830   d  up and down is further disposed, the antenna members  830   a ,  830   c  and  830   d  can be deformed in any shape. In this case, for example, when it is desired to bend the antenna member  830   a  upwardly at the central end, the lifting mechanism  87  corresponding to the antenna member  830   a  may be pulled up, and the lifting mechanisms  87  corresponding to the antenna members  830   c  and  830   d  may be fixed or lowered, and the antenna members  83  may be deformed by cooperating with a plurality of lifting mechanisms  87 . While it is not necessary to do so when the coupling member  831  is sufficiently soft to allow the antenna  83  to bend only by the corresponding lifting mechanism  87 . However, while the coupling member  831  may be deformable, when it is necessary to apply some force to the deformation, the plurality of lifting mechanism  87  may cooperate to perform the bending action of the antenna  83 . 
     The bending of the antenna  83  is performed by changing the angle formed between the antenna members  830   a  to  830   d  on both sides of the coupling member  831 , while serving the coupling member  831  as the fulcrum. 
     A linear encoder  88  is a device that detects the position of the linear axis and outputs position information. This allows accurate measurement of the distance of the antenna member  830   a  from the top face of the Faraday shield  95 . The linear encoder  88  may be disposed at any position where precise position information is desired, and a plurality of the linear encoders may be disposed. The linear encoder  88  may be any type including an optical, a magnetic, or an electromagnetic inductive type, as long as the position and height of the antenna  83  can be measured. Additionally, as long as the position and height of the antenna  83  can be measured, a height measuring unit other than the linear encoder  88  may be used. 
     The fulcrum jig  89  is a member for pivotally securing the lowermost antenna member  830 . This facilitates tilting the antenna  83 . Generally, the fulcrum jig  89  is provided to support the antenna member  830   b  of the lowermost stage at the end of the outer peripheral side. This is because, as noted above, the antenna  83  is often deformed to increase the center side. However, it is not mandatory to provide the fulcrum jig  89 , but rather it is preferable to provide the lifting mechanism  87  that moves the antenna member  830   b  up and down. 
     The connection electrode  86  includes an antenna connecting part  860  and an adjustment busbar  861 . The connection electrode  86  is a connection wire that serves as a framing to supply the antenna  83  with high frequency power output from the radio frequency power source  85 . The antenna connecting part  860  is an interconnection directly connected to the antenna  83 , and the adjustment busbar  861  is a part of the antenna connecting part  860  having a resilient structure to absorb the deformation when the antenna connecting part  860  is moved up and down by the vertical movement of the antenna  83 . Because the antenna connecting part  860  is an electrode, the antenna connecting part  860  is made with an electrically conductive material such as metal. 
     Thus, antenna device  81  and plasma generation apparatus  80  may be used that can automatically transform the shape of the antenna  83  into any shape. 
       FIG. 13  is a side view of an antenna  83  according to an embodiment of the present disclosure. As illustrated in  FIG. 13 , the bending angle of the antenna member  830  may be varied with the coupling member  831  as well as the height of the antenna member  830  depending on the location. 
     However, if the height of the antenna member  830   a  is too high, the distance between the bottom surface of the housing  90  and the antenna member  830   a  is increased, and the plasma power is unlikely to reach the vacuum chamber  1 . As a result, a phenomenon occurs where plasma is unlikely to ignite and unlikely to activate. Specifically, for example, if the height of the antenna member  830   a  is 20 mm or higher, such a phenomenon is likely to occur. 
     Thus, it is necessary to make the plasma intensity uniform between the central axis side and the outer peripheral side of the susceptor  2  without significantly increasing the distance between the antenna member  830   a  and the bottom surface of the housing  90 . 
     From this viewpoint, the height of the antenna member  830   a  is lowered as low as possible, and an ion trap plate  140  is provided in the vacuum chamber  1  to compensate for the lack of adjustment amount (see  FIG. 4 ). 
     [Ion Trap Plate] 
       FIG. 14  is a diagram illustrating an example of a plasma processing apparatus including an ion trap plate according to an embodiment.  FIG. 14  illustrates an enlarged plasma processing area P 3 .  FIG. 14  shows a plasma processing area P 3  transparently, but because the housing  90  is actually transparent, it is equivalent to a top view. As illustrated in  FIG. 4 , a plasma trap plate  140  is disposed in the vacuum chamber  1 . 
     As illustrated in  FIG. 14 , for example, the ion trap plate  140  is configured to overlap a portion of the outer edge of the bottom surface of the housing  90 . In  FIG. 14 , a portion of a covering area  83   c  between a point  83   a  and a point  83   b  of the antenna  83  is covered with the ion trap plate  140 . 
     The covering area  83   c  includes a broad area at the center of the susceptor  2  of the antenna  83 , but does not include the most outer area. That is, much of the central area of the antenna  83  is covered with the ion trap plate  140 , but the peripheral area of the antenna  83  is covered less or not at all. 
     Thus, by disposing an ion trap plate  140  in an area overlapping the antenna  83 , the ions generated by the plasma can be blocked and the oxidizing power of the plasma can be decreased. Thus, the ion trap plate  140  may be referred to as an ion block plate or an ion shield plate. Therefore, even if the set height of the antenna  83  (the antenna member  830   a ) is lowered, the oxidizing power of the central axis side region of the susceptor  2  is reduced, and the plasma oxidizing power in the radial direction can be made uniform. 
     The ion trap plate  140  may not necessarily trap ions, but may block ions, and it may be possible to partially restrict the supply of oxidizing gas ions to the wafer W in an area on the central axis side of the antenna  83 . 
     For example, it is possible to set the height of the antenna member  830   a  to 15 mm, 10 mm, 0 mm, and 15 mm or less and to prevent the plasma from being extinguished and from failing to ignite. 
     The shape of the ion trap plate  140  and the area overlapping the antenna  83  can be set in various ways depending on the use application. In  FIG. 14 , the planar shape of the ion trap plate  140  is configured to diagonally traverse the antenna  83 , but various modifications are possible depending on the use application. 
       FIG. 15  is a diagram illustrating an example of an ion trap plate  140 . The ion trap plate  140  has a circumferentially extending side  141  on the central axis side of the susceptor  2  and a radially extending side  145 . The ion trap plate  140 , in order to connect the end of the central axis side  141  to the outer peripheral end of radially extending side  145 , also has a radially obliquely extending side  142 , a circumferentially extending side  143 , and a curve  144  formed by rounding the sides  142  and  143  and curvaceously connecting the side  142  to the side  143  so as to form a curved angle. 
     Preferably, the ion trap plate  140  is literally formed as a plate. This is because the space in the vacuum chamber  1  is limited and because the thin plate shape is sufficient to perform a function of blocking or trapping ions. 
     A material for the ion trap plate  140  suitable to the application may be used as long as the ion trap plate can block or trap ions, and quartz may be used, for example. Quartz can be suitably utilized because the housing  90  is also quartz, and quartz can withstand high temperatures, and is unlikely to cause contamination. 
       FIG. 16  illustrates an example of a movable ion trap plate  146 . As illustrated in  FIG. 16 , a pivot shaft  150  may be disposed, and an area covering the antenna  83  may be changed by rotating the movable ion trap plate  146  about the pivot shaft  150 . 
     Preferably, when an ion trap plate is formed as the mobile ion trap plate  146 , the entire configuration is formed small and formed into a movable shape within the plasma processing area P 3 . In  FIG. 16 , the tip is narrowed and the overall width is smaller than the ion trap plate  140 . 
     The movable configuration allows adjustment of the amounts of trapped ions and blocked ions depending on the process, and fine adjustment of the oxidizing power. Thus, depending on the use application, such a mobile ion trap plate  146  may be adopted. 
       FIGS. 17A and 17B  are diagrams illustrating an example of an arrangement of an ion trap plate in a vacuum chamber  1 .  FIG. 17A  illustrates an example of an ion trap plate  147  disposed in a left area of the housing  90 . In this manner, the ion trap plate  147  can be positioned both on the right side and the left side as long as the ion trap plate  47  efficiently covers the area on the central axis side of the antenna  83 . 
       FIG. 17B  is a partial cross-sectional view illustrating an example of a vertical structure of a plasma processing apparatus including an ion trap plate  147 . As illustrated in  FIG. 17B , the ion trap plate  147  is disposed on the plasma processing gas nozzles  33  to  35 . The ion trap plate  147  may have a plurality of stops  148  and be fixed to the plasma processing gas nozzles  33  to  35 .  FIG. 17B  illustrates an example of the ion trap plate  147  being disposed on the plasma processing gas nozzles  33  to  35 , but the ion trap plate  147  may be supported by a separate support and disposed above the plasma processing gas nozzles  33  to  35 . 
     The ion trap plates  140  and  146  may be disposed in the vacuum chamber  1  in the same manner as the ion trap plate  147 . 
     By disposing ion trap plates  140 ,  146 , and  147  on or above the plasma processing gas nozzles  33  to  35 , ions can be trapped and the oxidizing power can be adjusted without hindering the flow of the plasma processing gas. 
     This reduces the tilt of the antenna  83  and maintains the plasma in a stable condition. 
     According to the embodiments of the present disclosure, the supply of ions generated by a plasma antenna can be adjusted. 
     All examples recited herein are intended for pedagogical purposes to aid the reader in understanding the disclosure and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority or inferiority of the disclosure. Although the embodiments of the present disclosure have been described in detail, it should be understood that various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the disclosure.