JP2013041703A - Line plasma generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly practical line plasma generator suitable for use in a wide beam source.SOLUTION: A line plasma generator 10 comprises a waveguide 14 which propagates microwaves in the longitudinal direction, and a magnet 16 disposed in the longitudinal direction and generating a magnetic field intersecting the longitudinal direction and confining the plasma in the waveguide 14. The waveguide 14 includes a ridge 26 projecting inward from the sidewall 24 and extending in the longitudinal direction, and the ridge 26 may form, in the outer surface of the sidewall 24, a recess 28 extending in the longitudinal direction. The magnet 16 may be disposed in the recess 28.

Description

  The present invention relates to a line plasma generator.

  A discharge tube for plasma generation is attached to a waveguide for inducing microwaves so that all or part of the discharge tube enters the waveguide, and a long line-shaped plasma is generated along the longitudinal axis of the discharge tube. A line plasma generator for generating is known. The long line-shaped plasma is used for plasma processing such as etching and cleaning processing in semiconductor processes, CVD processing of organic films, hydrophilic processing, or sterilization processing of foods and the like.

JP 2006-269151 A

  One further application of the line plasma generator is a beam source that outputs a wide beam (eg, an ion beam or an electron beam). In one attempt to obtain a wide beam, multiple filaments are placed side by side in a vacuum vessel for arc discharge. However, since the filament can be consumed in a short time, it is not always practically preferable. In some other attempts, an antenna for radiating high frequency power is inserted into the vacuum vessel, but the antenna can be damaged in a short time by sputtering of the plasma. In such attempts, there is also a problem that metal impurities can be released into the plasma from the filament or antenna.

  One exemplary object of one aspect of the present invention is the generation of a line plasma suitable for use in a wide beam source, for example, because it does not require consumable parts that are consumed in a short time for plasma generation. To provide an apparatus.

  One embodiment of the present invention is a line plasma generator. The apparatus generates a waveguide for propagating microwaves in the longitudinal direction and a magnetic field disposed along the longitudinal direction and intersecting the longitudinal direction for confining plasma in the waveguide. And a magnet.

  In addition, what replaced the component and expression of this invention between methods, apparatuses, systems, etc. is also effective as an aspect of this invention.

  According to the present invention, a line plasma generator excellent in practicality is provided.

It is a perspective view showing typically a line plasma generator concerning one embodiment of the present invention. It is sectional drawing of the line plasma generator which concerns on one Embodiment of this invention. It is a figure which shows an example of magnetic field strength distribution in the plasma production part of the line plasma generator which concerns on one Embodiment of this invention. It is sectional drawing of the line plasma generator which concerns on one modification. It is sectional drawing of the line plasma generator which concerns on one modification. It is sectional drawing of the line plasma generator which concerns on one modification.

  FIG. 1 is a perspective view schematically showing a line plasma generator 10 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the line plasma generator 10 according to one embodiment of the present invention. FIG. 2 shows a cross section perpendicular to the longitudinal direction L of the line plasma generator 10.

  One application of the line plasma generator 10 according to one embodiment of the present invention is a wide beam source. The wide beam is, for example, a charged particle beam extracted from plasma. The charged particle beam may be an ion beam or an electron beam. The wide beam may be a light or electromagnetic beam emitted from plasma.

  Therefore, the line plasma generator 10 may be an ion source for an ion implanter. In that case, the line plasma generator 10 is configured to generate a high-density plasma by inputting microwave power to the plasma generator 12 to which a magnetic field higher than the resonant magnetic field is applied, and to extract ions from the plasma. The Since a wide ion beam extending in the longitudinal direction L is generated from the line-shaped plasma, the line plasma generation apparatus 10 is suitable for an ion source of an ion implantation apparatus for performing ion implantation processing on a large substrate. Such large substrates include, for example, substrates for flat panel displays and substrates for solar cells. A wide ion beam is sometimes called a ribbon beam.

  Further, the line plasma generator 10 may be an electron source. In that case, the line plasma generator 10 is configured to extract electrons from the plasma generated by the plasma generator 12, for example. Since a wide electron beam is generated in the line direction from the line-shaped plasma, the line plasma generator 10 is suitable for an electron source for suppressing charge-up of a substrate in an ion implantation apparatus using a wide ion beam, for example. It is.

  A line plasma generator 10 according to an embodiment of the present invention is configured to generate a plasma of a raw material gas in a plasma generator 12 by an interaction between a microwave and a magnetic field. The line plasma generator 10 includes a waveguide 14 for propagating microwaves in the longitudinal direction L, and a magnet 16 disposed along the longitudinal direction L. The waveguide 14 includes a plasma generation unit 12 that extends in the direction in which microwave power is introduced. The plasma generation unit 12 is an internal region of the waveguide 14 and is a space for accommodating the generated plasma. The line plasma generator 10 is configured to confine plasma in the plasma accommodating space (that is, the plasma generation unit 12) with a magnetic field by the magnet 16.

  In the present application, in order to describe the positional relationship with respect to the waveguide 14, it may be referred to as “vertical direction” and “lateral direction”. The longitudinal direction represents the longitudinal direction L in which the waveguide 14 extends or the tube axis direction of the waveguide 14. The lateral direction represents a direction that intersects the longitudinal direction L of the waveguide 14, usually a direction that is orthogonal.

  Also, in order to describe the relative position with respect to the waveguide 14, “upper” or “upper” or the like is used to refer to a portion of the waveguide 14 in which an outlet 18 for taking out a wide beam is provided. And may be referred to as “lower side” or “downward” in order to indicate a portion of the waveguide 14 (for example, a portion where the magnet 16 is installed) facing the outlet 18. However, this is for convenience of explanation, and does not mean that the outlet 18 and the magnet 16 must be arranged along the vertical direction (that is, the direction in which gravity acts). For example, the line plasma generator 10 may be used in a state where the outlet 18 of the waveguide 14 and the magnet 16 are horizontally oriented.

  The line plasma generator 10 is placed in a vacuum environment when used. For example, the line plasma generator 10 is accommodated in a vacuum chamber of a vacuum processing apparatus (for example, an ion implantation apparatus) on which the line plasma generator 10 is mounted. Therefore, the plasma generation unit 12 has a degree of vacuum corresponding to the surrounding vacuum environment.

  The line plasma generator 10 includes a microwave supply system (not shown) for supplying the microwave A to the waveguide 14. The microwave supply system is configured to input microwave power into the tube through the vacuum window 20 of the waveguide 14. The microwave supply system includes a known configuration including, for example, a microwave power source, a transmission path for transmitting microwaves from the power source to the waveguide 14, and a matching unit for reducing power reflection toward the microwave power source. It may be. In the illustrated example, the introduction direction of the microwave A from the end of the microwave supply system (for example, the matching portion) to the waveguide 14 coincides with the longitudinal direction L of the waveguide 14. The microwave A incident on the waveguide 14 propagates in the waveguide 14 in the vertical direction. For example, microwave power having a frequency of 2.45 GHz is supplied to the waveguide 14.

  The line plasma generator 10 includes a gas supply system 22 for supplying a plasma source gas C to the plasma generator 12. The source gas C is, for example, argon gas. The source gas C may include a component containing impurities for ion implantation. As shown in the figure, a terminal pipe of the gas supply system 22 is connected to the waveguide 14. This pipe is connected to the side wall 24 of the waveguide 14 extending in the longitudinal direction L, for example. The source gas C is supplied to the plasma generator 12 through the pipe. The gas supply system 22 may include a gas source and a gas flow rate controller that controls the supply flow rate of the source gas C from the gas source to the plasma generation unit 12.

  The waveguide 14 is a hollow pipe made of metal (for example, nonmagnetic metal material), for example. Therefore, the waveguide 14 includes a cylindrical side wall 24 extending in the longitudinal direction L. In the following, the side wall 24 may be referred to as a waveguide side wall 24. The waveguide sidewall 24 has a desired length. The length of the waveguide side wall 24 is determined according to, for example, a desired width of the wide beam. A vacuum window 20 for receiving microwave power from a microwave supply system is formed at one end of the waveguide side wall 24. The vacuum window 20 is made of a dielectric material, for example. The other end of the waveguide side wall 24 is closed. The waveguide side wall 24 is adjacent to the magnet 16 extending in the longitudinal direction L, as will be described later.

  In this embodiment, the waveguide 14 is a ridge waveguide. The waveguide 14 includes a ridge portion 26 formed to protrude from a side wall 24 having a rectangular cross section into the tube. The ridge portion 26 extends in the longitudinal direction L from one end of the waveguide 14 to the other end. The ridge portion 26 forms a recess 28 extending in the longitudinal direction L on the outer surface of the side wall 24. Therefore, the waveguide 14 has the recessed part 28 in the cross section seen from the microwave power introduction direction. As will be described later, the magnet 16 can be accommodated in the recess 28. The upper surface 30 of the waveguide side wall 24 facing the ridge portion 26 is formed flat.

  Note that the ridge portion 26 may be solid. In this case, the recess 28 is not formed in the waveguide side wall 24, and the lower outer surface of the waveguide side wall 24 may be formed flat, for example. In addition, a second ridge portion facing the lower ridge portion 26 may be formed on the upper surface 30 of the waveguide side wall 24. A later-described extraction electrode 36 may be accommodated in a second recess formed on the outer surface of the upper surface 30 by the second ridge portion.

  The ridge portion 26 is formed at the center in the width direction of the waveguide 14. Therefore, the height in the waveguide 14 (that is, the distance between a pair of opposing side walls) is relatively small in the ridge portion 26 and relatively large on both sides (outside in the width direction) of the ridge portion 26. Yes. In the ridge waveguide, the electric field due to the microwave A becomes strong at the central portion where the ridge portion 26 is located. The plasma generation unit 12 is formed between the ridge portion 26 and the waveguide upper surface 30. Therefore, plasma can be efficiently generated in a region where the microwave electric field is strong.

  The waveguide 14 includes a dielectric 32 that extends along the longitudinal direction L within the tube. The dielectric 32 may be, for example, a BN (boron nitride) material or alumina. Such a material is preferable in that it has a low loss with respect to the microwave A and has plasma resistance and heat resistance.

  The dielectric 32 is filled so as to define the plasma generation unit 12 in the waveguide 14. The inner surface of the waveguide 14 is covered with a dielectric 32 except for the outlet 18 side. Specifically, the inner surface of the ridge portion 26 is covered with a dielectric 32. Further, both sides of the ridge portion 26 are filled with a dielectric 32. Of the inner surface of the upper surface 30, the peripheral portion of the outlet 18 is exposed. Thus, the plasma generation unit 12 is defined by the waveguide inner surface on the outlet 18 side and the surface of the dielectric 32. The plasma generator 12 has a rectangular cross section perpendicular to the longitudinal direction L.

  The magnet 16 is configured to generate a transverse magnetic field for confining plasma in the waveguide 14. In this embodiment, the magnet 16 is a permanent magnet. The magnet 16 has one magnetic pole on the surface directed to the plasma generation unit 12 and the other magnetic pole on the opposite surface. The magnetization direction of the magnet 16 is indicated by an arrow B in FIG. The magnetization direction may be opposite to the illustrated direction. The magnet 16 may include a plurality of magnets arranged in the longitudinal direction L.

  The magnet 16 is disposed outside the ridge portion 26 of the waveguide 14 and is accommodated in the recess 28. In the illustrated example, the width of the magnet 16 is made equal to the width of the recess 28. In order to align the direction of the lines of magnetic force in the plasma generation unit 12, the width of the magnet 16 is preferably equal to or greater than the width of the plasma generation unit 12. The magnet 16 (or the arrangement of a plurality of magnets) has at least a length equal to or longer than the length in the longitudinal direction L of the plasma generation unit 12 and has a length corresponding to, for example, the waveguide 14.

  Thus, the lines of magnetic force are generally directed from the ridge portion 26 to the outlet 18. The magnet 16 generates a magnetic field perpendicular to the microwave power introduction direction. The plasma is confined in the waveguide 14 by this magnetic field. In order to promote the generation of high-density plasma, the magnet 16 is preferably configured so that a magnetic field (resonance magnetic field) that causes electron cyclotron resonance is applied to the plasma generation unit 12.

  An outlet 18 for taking out a wide beam to the outside of the waveguide 14 is formed in the waveguide 14. In the waveguide 14, at least one outlet 18 is formed in the waveguide side wall 24 along the longitudinal direction L. The plasma generator 12 communicates with the outside of the waveguide 14 through the outlet 18. The outlet 18 is an opening that is physically open so that charged particles can pass through. However, when the beam extracted from the plasma to the outside is light or electromagnetic waves, the outlet 18 is not necessarily required to be physically opened as long as the beam can be transmitted.

  The outlet 18 is formed on the surface of the waveguide side wall 24 facing the ridge portion 26. In the illustrated example, a plurality of circular openings are arranged in the waveguide side wall 24 along the longitudinal direction L. Instead of forming a plurality of openings, one or more slits extending in the longitudinal direction L may be formed in the waveguide sidewall 24. The opening shape of the outlet 18 is arbitrary, and may be a round hole, a long hole, a square hole, or a slit-like opening extending from one end to the other end of the waveguide 14. The dimensions of the outlet 18 including at least one of the shape, diameter, radius, width, length, number, and pitch of the outlet 18 can be appropriately set according to the application of the line plasma generator 10.

  The outlet 18 may be formed in a drawing member 34 that is separate from the waveguide 14. The extraction member 34 constitutes a part of the waveguide side wall 24. The extraction member 34 is configured to be replaceable with respect to the waveguide 14. The drawing member 34 is a plate-like member made of a material having plasma resistance (for example, graphite). The extraction member 34 has a planar shape corresponding to the plasma generation unit 12 extending in the longitudinal direction L. Thus, the plasma generation unit 12 can be defined by the extraction member 34 and the dielectric 32. In this case, the metal portion of the waveguide 14 can be completely covered with the dielectric 32 to be protected from the plasma. The drawing member 34 can be easily removed and replaced or maintained as necessary.

  The line plasma generator 10 includes at least one extraction electrode 36 for extracting charged particles from the plasma generator 12 through the outlet 18 to the outside of the waveguide 14 (see FIG. 2). The extraction electrode 36 is provided to face the extraction outlet 18. The extraction electrode 36 has a distance from the waveguide sidewall 24 and extends in the longitudinal direction L in parallel with the waveguide 14. The extraction electrode 36 has an opening 38 through which the beam passes at a position corresponding to the extraction outlet 18. The extraction electrode 36 may include two electrodes arranged in parallel, one of which may be configured as a ground electrode, and an extraction voltage may be applied to the other electrode.

  The extraction electrode 36 is connected to an extraction power source 40. The extraction power supply 40 is configured to apply an extraction voltage for extracting charged particles from the plasma generation unit 12 between the extraction electrode 36 and the waveguide 14. Alternatively, the extraction power supply 40 is configured to apply an extraction voltage between the extraction member 34 and the extraction electrode 36.

  The extraction power supply 40 may be configured to change the polarity of the extraction voltage applied between the extraction electrode 36 and the waveguide 14 (or the extraction member 34). In this way, positive ions can be extracted from the plasma generation unit 12 in the case of one polarity, and electrons can be extracted from the plasma generation unit 12 in the case of the other polarity. The line plasma generator 10 can be used by switching between an ion source and an electron source.

  The line plasma generator 10 may include a yoke 42 that covers the waveguide 14. The yoke 42 surrounds the waveguide 14 to locally concentrate the transverse magnetic field of the magnet 16 within the waveguide 14. The yoke 42 is configured to concentrate the magnetic field on the plasma generation unit 12 and reduce the leakage magnetic field to the outside. The yoke 42 covers the outer surfaces of the waveguide 14 and the magnet 16. Note that the line plasma generator 10 does not necessarily include the yoke 42 when a sufficient magnetic field is applied to the plasma generator 12 by the magnet 16.

  The yoke 42 together with the magnet 16 forms a closed magnetic circuit for generating a magnetic field directed from the top to the bottom (or from the bottom to the top) in the plasma generator 12. The yoke 42 places one magnetic pole at the upper end of the plasma generating unit 12 and the other magnetic pole at the lower end of the plasma generating unit 12.

  A slit 44 is formed along the longitudinal direction L on the upper surface of the yoke 42. The planar shape of the slit 44 matches the planar shape of the drawing member 34 or includes the planar shape of the drawing member 34. Thereby, it is easy to replace or remove the drawing member 34 through the slit 44 of the yoke 42. Note that the yoke 42 may not have the slit 44, and in that case, the yoke 42 may cover the entire outer surface of the waveguide 14 except the outlet 18.

  FIG. 3 is a diagram illustrating an example of a magnetic field strength distribution in the plasma generation unit 12 of the line plasma generation apparatus 10 according to an embodiment of the present invention. FIG. 3 shows the calculation result of the magnetic field strength distribution for the right half of the cross section shown in FIG. FIG. 3 shows the plasma generation unit 12, the magnet 16, and the yoke. The dielectric 32 and the waveguide side wall 24 that are transparent to the static magnetic field are not shown in FIG.

  As illustrated, a magnetic field directed from the lower magnet 16 side to the upper outlet 18 side is generated in the plasma generation unit 12. In this example, the strength of the magnetic field in the plasma generator 12 is about 40 mT (400 gauss) on the outlet 18 side, and about 220 mT (2200 gauss) at the maximum on the magnet 16 side. The strength of the magnetic field that causes electron cyclotron resonance is uniquely determined with respect to the microwave frequency to be used. When the microwave frequency is 2.45 GHz, a magnetic field of 87.5 mT (875 gauss) is required. Thus, the magnetic field of this example is large enough to cause electron cyclotron resonance.

  Operation | movement of the line plasma generator 10 which concerns on one Embodiment of this invention is demonstrated. When the operation of the line plasma generator 10 is stopped, a transverse static magnetic field generated by the magnet 16 is generated in the plasma generator 12. This magnetic field is, for example, the magnetic field shown in FIG. When the operation of the line plasma generator 10 is started, the source gas is supplied from the gas supply system 22 to the plasma generator 12. A microwave is introduced from the vacuum window 20 into the plasma generator 12 in the vertical direction.

  The source gas is excited by the microwave, and plasma is generated in the plasma generation unit 12. In addition, electron cyclotron resonance is generated by the action of the microwave and the magnetic field, and absorption of electron microwave energy is further promoted. This also generates plasma in the plasma generator 12. An extraction voltage is applied to the extraction electrode 36. Ions (or electrons) are extracted from the plasma through the extraction outlet 18 by the extraction electrode 36. Thus, a wide ion beam (or electron beam) extending in the longitudinal direction L can be obtained.

  The line plasma generation apparatus 10 according to an embodiment of the present invention does not include consumable parts such as a filament and an antenna in the plasma generation unit 12. Therefore, a plasma generation operation for a long period of time is possible without being influenced by the lifetime of such consumable parts. In addition, there is an advantage that metal impurities are not mixed into the plasma due to wear of these parts.

  With reference to FIG. 4 thru | or FIG. 6, some modifications of the line plasma generator 10 are demonstrated. The embodiment shown in FIG. 4 is similar to the embodiment described with reference to FIGS. 1 to 3 except that it includes a cooling means for the waveguide 14. In the following description, the description of similar parts will be omitted as appropriate to avoid redundancy.

  FIG. 4 is a cross-sectional view of a line plasma generator 10 according to a modification. The line plasma generator 10 includes a cooling system 46 for cooling the waveguide 14. The cooling system 46 includes a coolant flow path formed between the waveguide 14 and the yoke 42. In addition, the cooling system 46 includes a coolant channel formed between the waveguide 14 and the magnet 16. This refrigerant flow path is, for example, a water jacket. The cooling system 46 is in contact with the waveguide 14 which can be hot. Therefore, the cooling system 46 can cool the waveguide 14 efficiently.

  The cooling system 46 may include a refrigerant source or pump for supplying or circulating refrigerant (eg, cooling water) to the refrigerant flow path. The coolant flow path of the cooling system 46 may not be formed between the outer surface of the waveguide 24 and the inner surface of the yoke 42. The coolant flow path of the cooling system 46 may be located anywhere between the inner surface of the waveguide 24 and the outer surface of the yoke 42, and may be formed in the waveguide side wall 24 or the yoke 42, for example.

  FIG. 5 is a cross-sectional view of a line plasma generator 10 according to a modification. The embodiment shown in FIG. 5 is the same as the embodiment described with reference to FIGS. 1 to 3 except for the configuration of the yoke 42. In the following description, the description of similar parts will be omitted as appropriate to avoid redundancy. The configuration of the yoke 42 described with reference to FIG. 5 may be applied to the embodiment shown in FIG.

  The yoke 42 includes a removable yoke portion 48. A removable yoke portion 48 covers the portion of the waveguide 14 in which the outlet 18 is formed. The removable yoke portion 48 has a shape that fits the slit 44. The removable yoke portion 48 has an opening 50 at a location corresponding to the outlet 18. Therefore, the entire waveguide 14 except for the outlet 18 is surrounded by the yoke 42. Since the plasma generating unit 12 is entirely surrounded by the yoke 42, the leakage magnetic field to the outside can be further reduced.

  FIG. 6 is a cross-sectional view of a line plasma generator 10 according to a modification. The embodiment shown in FIG. 5 is the same as the embodiment described with reference to FIGS. 1 to 3 except for the configuration of the magnet 16. In the following description, the description of similar parts will be omitted as appropriate to avoid redundancy. The configuration of the magnet 16 described with reference to FIG. 6 may be applied to the embodiment shown in FIG. 4 or the embodiment shown in FIG.

  The magnet 16 shown in FIG. 6 is an electromagnet. Therefore, the magnet 16 includes a coil 52 and an iron core 54. The iron core 54 extends in the longitudinal direction L, is disposed outside the ridge portion 26 of the waveguide 14, and is accommodated in the recess 28. A conducting wire of the coil 52 is wound around the iron core 54 to constitute an electromagnet. A current is supplied to the coil 52 to provide the illustrated magnetization direction B (or the opposite direction). The magnet 16 (electromagnet) shown in FIG. 6 is configured to generate a transverse magnetic field similar to the magnet 16 (permanent magnet) shown in FIGS.

  Note that when a sufficient magnetic field is applied to the plasma generation unit 12, the line plasma generation apparatus 10 may not include at least one of the iron core 54 and the yoke 42. Further, the magnet 16 may include both an electromagnet and a permanent magnet.

  When the line plasma generator 10 is used as an ion source, it may be preferable to be able to control the strength of the magnetic field generated in the plasma generator 12. Therefore, in that case, the magnet 16 preferably includes an electromagnet. When the line plasma generator 10 is used as an electron source, it may be sufficient that a constant magnetic field is generated in the plasma generator 12. Therefore, in that case, the magnet 16 is preferably a permanent magnet.

  In the above, this invention was demonstrated based on the Example. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiment, and various design changes are possible, various modifications are possible, and such modifications are within the scope of the present invention. By the way.

  The positional relationship between the outlet 18 and the magnet 16 may be reversed. That is, the outlet 18 may be formed in the ridge portion 26. The magnet 16 may be installed on a portion of the surface of the waveguide 14 that faces the ridge portion 26.

  The shape of the cross section perpendicular to the longitudinal direction L of the waveguide 14 is arbitrary. The waveguide 14 may not have the ridge portion 26. For example, the waveguide 14 may be a rectangular waveguide having a rectangular cross section or a circular waveguide having a circular cross section. In these cases, the outlet 18 is formed on the side wall of the waveguide 14 so as to face the portion of the waveguide 14 that is close to (or in contact with) the magnet 16. A plasma generation unit 12 is formed in the inner region of the waveguide 14 between the magnet 16 and the outlet 18, and a magnetic field generated by the magnet 16 is generated in the plasma generation unit 12. Note that the magnet 16 and the outlet 18 do not have to face each other. The magnet 16 may be provided at any position that generates a transverse magnetic field in the plasma generator 12.

  10 line plasma generator, 14 waveguide, 16 magnet, 18 outlet, 26 ridge, 28 recess, 32 dielectric, 36 extraction electrode, 38 opening, 42 yoke, A microwave, B magnetization direction, L longitudinal direction .

Claims (8)

A waveguide for propagating microwaves in the longitudinal direction;
A line plasma generator, comprising: a magnet disposed along the longitudinal direction and generating a magnetic field intersecting the longitudinal direction for confining plasma in the waveguide. The waveguide includes a ridge portion that protrudes from the side wall into the tube and extends in the longitudinal direction, and the ridge portion forms a recess extending in the longitudinal direction on the outer surface of the side wall,
The line plasma generator according to claim 1, wherein the magnet is disposed in the recess.   The line plasma generation apparatus according to claim 1, further comprising a yoke surrounding the waveguide in order to concentrate the magnetic field locally in the waveguide.   The line plasma generator according to claim 3, wherein a coolant channel for cooling the waveguide is formed between the waveguide and the yoke.   5. The line plasma generator according to claim 3, wherein the yoke includes a removable yoke portion for covering a portion of the waveguide in which an opening is formed. The waveguide has at least one outlet formed along the longitudinal direction;
The line plasma according to any one of claims 1 to 5, further comprising an extraction electrode facing the extraction port and for extracting charged particles from the plasma through the extraction port to the outside of the waveguide. Generator.   The line plasma generator according to claim 6, wherein a polarity of an extraction voltage applied between the extraction electrode and the waveguide is changeable.   The line plasma generator according to claim 1, wherein the waveguide includes a dielectric material filled to define a space for confining the plasma.