JP2004047207A - Method and device of generating ground wave excitation plasma at conductor proximity area - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device of generating ground wave excitation plasma at a conductor proximity area. <P>SOLUTION: The device is provided with a target 16 made of a conductor arranged so that at least its one end come close to a microwave supply opening 12a in a chamber 11, a dielectric window 15 arranged inside the microwave supply opening, a means of initially generating a plasma phase in the vicinity of the surface of the target, and a bias power supply 18 for enlarging a low-electron density sheath area between the plasma phase initially generated by applying a negative bias voltage on the target and the target surface. The generating device of the ground wave excitation plasma is so constructed to apply a plasma treatment on the target itself or on the surface of a processed material 20 when arranged in contact with the plasma phase by the ground wave excitation plasma at an interface between the plasma phase 21 and the low-electron density sheath area. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and apparatus for generating a surface wave excited plasma along a non-dielectric region, particularly a conductive metal surface.
[0002]
[Prior art]
2. Description of the Related Art In recent years, sputtering, etching, ashing, cleaning, or plasma processing such as plasma CVD is often used for surface treatment of various organic materials, metal materials, and the like, including semiconductor substrates and liquid crystal glass substrates. In order to generate plasma at a high density, a magnetron method or an ECR discharge is generally employed. However, these magnetic field methods have low energy efficiency, are complicated and expensive, and have many adverse effects such as radio interference. Therefore, in plasma processing, it is important that the main source of plasma is a magnetic field-free system and that a plasma phase having a uniform density distribution corresponding to the shape of the surface to be processed is first formed.
[0003]
Attention has been paid to a so-called surface-wave-excited plasma method. For example, in Japanese Patent Application Laid-Open No. H11-102799, a microwave is applied along the surface of a dielectric material positioned at the center of a plasma chamber. By the propagation, the electromagnetic field energy is concentrated near this surface to generate a high-density plasma, and the expansion of the plasma phase causes a relatively uniform and high-density plasma to be applied to the substrate disposed at the bottom in the chamber. There is disclosed a surface wave excitation type plasma generating apparatus for applying plasma.
[0004]
However, in the plasma generator disclosed in this publication, a dielectric tube or rod surrounding the microwave transmission antenna or connected to the microwave emission slit is suspended from the top surface of the plasma chamber, and is intended for plasma sputtering. In this case, it is difficult to adopt a configuration in which a material other than a dielectric, typically a metal, is used as a target, and a substrate to be processed or the like is opposed to the target and plasma sputtering and film formation are performed. A similar drawback exists when using the plate-type dielectric described in the above publication as a prior art.
[0005]
Therefore, when performing sputtering using surface wave excited plasma, if the target material exists in the surface wave propagation region where the plasma is generated at the highest density, the target material will have the maximum efficiency due to the collision of plasma particles. It was noted that a sputtered film could be effectively formed on the surface of the workpiece facing or surrounding the atom emitting surface. Therefore, when a metal body is targeted, microwaves need only be propagated along the surface of the metal body.
[0006]
[Problems to be solved by the invention]
However, as shown schematically in FIG. 1A, the “surface” in the case of generating the surface wave excited plasma means the interface 3 between the plasma phase 1 at a certain or more electron (ion) density and the dielectric 2 in contact with it. The microwave 4 supplied from one end is propagated (as a surface wave) in a state where the energy of the electromagnetic wave is concentrated on this interface. As a result, the plasma phase 1 in contact with the interface 3 is excited and amplified by a surface wave of high energy density to generate and maintain a high-density plasma phase. Cannot generally produce favorable surface wave propagation and plasma excitation because they are electrically conductive.
[0007]
On the other hand, a charged particle layer of a single polarity, a so-called sheath, is formed essentially near the surface of the object in contact with the plasma phase, but when the object is a metal conductor to which a negative bias voltage is applied, the sheath is an electron. This is a layer having a low density (accordingly, a positive polarity) and a layer having a dielectric constant ε ≒ 1. For this reason, if the thickness of the sheath layer can be increased by increasing the negative bias voltage, as shown in FIG. 1B, the dielectric material that propagates the surface wave 4 to the interface with the plasma phase 1 by using the sheath layer 5 is provided. As a result, the surface of the metal conductor 6 can be directly subjected to ion bombardment by high-density excited plasma based on the surface wave 4 to perform sputtering.
[0008]
This is confirmed by the experimental method and the schematic diagram of the experimental results shown in FIG. In the experimental apparatus shown in FIG. 2A, a target metal rod 6a having conductivity is protruded from a quartz window 8 at one end of a plasma chamber 7 capable of vacuum suction into the chamber 7, and the outer surface of the quartz window 8 is guided. Connected to the microwave outlet of tube 9. An adjustable negative bias power supply Eb is connected to the target metal rod 6a. Thus, the chamber 7 is supplied with argon Ar, which is an inert gas suitable for the experiment, and is appropriately decompressed / suctioned (Suc.). The microwave, for example, f = 2.45 GHz, is output from the waveguide 9. The propagation and propagation of the surface wave on the inner surface of the quartz window 8 as a dielectric and the space surrounding the metal rod 6a and the state of plasma excitation were observed by emitting and supplying the electromagnetic wave.
[0009]
FIG. 2B shows that when a microwave is applied to the quartz window 8 without applying a bias voltage to the target metal rod 6a (Eb = 0 volt), the surface wave is standing inside the quartz window 8, FIG. 2B is a schematic diagram of an image obtained from a photograph of plasma excited and emitted in the vicinity thereof taken in a dark room (chamber) along a line of sight CL in FIG. 2A. Although the clear plasma 10 is limited to the peripheral region of the inner surface of the quartz window 8, there should be a fine and invisible plasma diffusion phase also in the projecting direction of the metal rod 6a. Such a plasma 10 can be used as the initial ignition (initial generation of the plasma phase) of the surface wave excited plasma in the present invention.
[0010]
FIG. 2C shows that, by applying a negative bias voltage (Eb = −150 volts) to the target metal bar 6a from this state, a plasma phase 10 ′ was formed along the metal bar 6a by photographing. It was confirmed and shown schematically. As described above, as a result of applying the microwave and applying the negative bias voltage to the metal bar 6a, a high-density plasma phase 10 'could be formed along the metal bar 6a. Along with a relatively thick sheath 5, the microwaves propagate along the interface between the sheath and the plasma phase 10 ′ (as surface waves) and have the synergistic effect of further exciting the plasma phase 10 ′. It has occurred.
[0011]
One object of the present invention is to elucidate the above, a surface wave excited plasma phenomenon without a dielectric substance in the vicinity of a target made of a conductor such as a metal, and therefore, a surface wave using a conductor target itself as a surface wave antenna. An object of the present invention is to provide a plasma generation method and apparatus suitable for performing plasma processing such as sputtering or ion implantation using excited plasma.
[0012]
A second object of the present invention is to perform high-density plasma generation in a cylindrical space, which has been considered difficult when performing tube inner surface processing or surface processing of a rod-shaped body with plasma, at a relatively low cost. An object of the present invention is to provide a method and an apparatus for generating surface wave excited plasma in the vicinity of a conductor target.
[0013]
[Means for Solving the Problems]
In the method for generating surface wave excited plasma according to the present invention, a target made of a conductor is arranged so that at least one end thereof is close to a microwave supply port, and a plasma phase is initially generated close to the surface of the target, By emitting a microwave from a microwave supply port and applying a negative bias voltage to the target, a sheath region having a low electron density generated near the target surface in opposition to the plasma phase is enlarged, and the emitted The microwave is propagated from the one end to the other end along the boundary between the sheath region and the plasma phase, so that the target functions as a surface wave antenna and generates surface wave excited plasma.
[0014]
In order to perform typical initial ignition in the implementation of the above method, that is, initial generation of a plasma phase, in the present invention, a dielectric is interposed in the microwave supply port, and the microwave emitted from the microwave supply port is used as the dielectric substance. To propagate as a surface wave on the dielectric surface close to the target surface, and initially generate a plasma phase composed of surface wave excited plasma in this proximity region.
[0015]
In the implementation of the above method, a plasma chamber having a plasma generating gas inlet and an exhaust port and having the microwave supply port connected thereto is provided, and in the chamber, at least one end of the target is close to the microwave supply port. By arranging them so that they can be performed, it can be carried out with a desired plasma generating gas and a desired pressure (or degree of vacuum).
[0016]
The basic configuration of the surface-wave-excited plasma generator according to the present invention includes a waveguide that guides microwaves, a target made of a conductor that is electrically insulated and protruded from the end of the waveguide, and A power supply for applying a negative bias voltage, and generating a surface wave excited plasma by propagation of microwaves along a sheath region having a low electron density formed according to the magnitude of the bias voltage around the target. The plasma processing can be performed on the surface of the material to be processed facing the surface of the target.
[0017]
A typical configuration of the surface wave excited plasma generating apparatus according to the present invention includes a plasma chamber having a plasma generating gas inlet, an exhaust port, and a microwave supply port, and at least one end of the plasma chamber having the microwave. A target made of a conductor disposed close to the supply port, a dielectric window disposed substantially across the microwave supply port, and initializing a plasma phase close to the surface of the target. And a bias power supply for enlarging a low electron density sheath region between the initially generated plasma phase and the target surface by applying a negative bias voltage to the target. The surface wave excited plasma at the interface with the electron density sheath region makes the target itself or the plasma phase The surface of the work piece when placed in is obtained so as to plasma processing.
[0018]
In the above-described apparatus, the means for initially generating the plasma phase in the chamber may include the initial ignition by the dielectric interposed in the microwave supply port, which has already been described in relation to the implementation of the method of the present invention, and the ignition discharge in the bias power supply. Circuit means for superimposing an AC voltage for use on the negative bias voltage. The superimposition of the AC voltage on the negative bias voltage by this circuit means can be selectively performed with an appropriate value for promoting the plasma discharge even after the ignition discharge.
[0019]
Still another means for initially generating the plasma phase in the chamber includes a magnetic field generation comprising a permanent magnet or an electromagnet surrounding the chamber and magnetically exciting at least a region close to the dielectric window. Means can be used. Further, after the ignition of the initial plasma phase, a magnetic field for confining plasma surrounding the inside of the peripheral wall of the chamber can be generated using the magnetic field generating means itself or another magnetic field generating means.
[0020]
In the plasma generator of the present invention, (1) the target made of a conductor is a rod, and the introduced microwave is propagated along the outer peripheral surface of the target to cover the rod. Efficient film formation by sputtering metal on the inner surface of the processing cylinder, or ion implantation to a rod-shaped target, (2) a target made of a conductor is formed into a cylindrical body, The wave is propagated along the inner peripheral surface of the target, so that an effective film is formed on the outer surface of the surrounding rod-shaped body (workpiece) by a sputtering metal, or to the cylindrical target metal. (3) making the target made of a conductor a plate-like body, and applying the introduced microwave to the target The film is propagated along the surface of the substrate facing the inside of the chamber, so that an effective film is formed by sputtering metal on the surface of the substrate to be processed, or ion implantation is performed on the cylindrical target metal. It is possible.
[0021]
However, in the above-described plasma generator, it is not essential to perform film formation on the workpiece or to perform ion implantation on the conductor target itself, but to adjust the negative bias voltage to the target. And the like, and high density plasma (10 ¹¹ -10 ¹² cm ^-3 ) Is expected to be applied to new application fields. Hereinafter, a preferred embodiment of the present invention will be described with reference to FIGS.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 3 is a sectional view and an electrical connection diagram of a main part of the basic structure according to the first embodiment. In FIG. 3, reference numeral 11 denotes a vacuum vessel constituting a plasma chamber, and 12 denotes a microwave supply which is bent and connected to the upper end of the vessel in order to supply a microwave of, for example, 2.45 GHz from the microwave oscillator 13 to the vacuum vessel 11. This is a waveguide having an opening 12a. The microwave oscillator 13 is connected to and driven by a drive power supply 14.
[0023]
In this case, the vacuum vessel 11 is made of metal and has an upright drum shape, and has a structure in which a center opening at an upper end is covered from outside with a plate-shaped dielectric window 15, and hangs down from the dielectric window 15. It encloses a substantial part of the supported rod-shaped target 16 made of a conductor such as copper, for example, and its lower end is slightly projected from the lower insulating plate 17 on the lower end wall of the container for electrical connection. Reference numeral 18 denotes a bias power supply for applying a plasma excitation / promotion voltage including an AC voltage mainly including a DC voltage for obtaining a negative bias to the rod-shaped target 16. Can be controlled.
[0024]
The microwave supply port 12a of the waveguide 12 has a coaxial cylindrical conductor 12c protruding from an insulating truncated cone 12b in order to form a coaxial waveguide circuit, and the tip of the cylindrical conductor 12c is a dielectric. The supporting concave surface of the window 15 occupies a position back to back with the base end of the rod-shaped target 16. As described above, the dielectric window 15 can be used for initial ignition of plasma, but another effective initial ignition means is an ECR excitation in the form of an upper plate of a vacuum container along the outer periphery of the tip of the microwave supply port 12a. An array of permanent magnets or magnet coils 19 can be arranged as desired.
[0025]
Thus, in the apparatus of this embodiment, the cylindrical work material 20 is surrounded by the suitable support means (not shown) around the rod-shaped target 16, preferably coaxially, in the vacuum vessel 11. It can be placed and subjected to plasma processing. For example, argon is supplied into the vacuum chamber 11 from the plasma generating gas inlet 11a, and the vacuum is appropriately suctioned from the exhaust port 11b to adjust the internal pressure appropriately. Next, a microwave of 2.45 GHz is supplied from the microwave oscillator 13 to the vacuum vessel 11 through the waveguide 12. As a result, the microwave becomes a surface wave along the surface of the dielectric plate 15 corresponding to the base of the rod-shaped target 16, and propagates or stands to excite the surrounding gas phase to initially ignite the plasma phase. This initial plasma phase naturally exists near the base of the rod-shaped target 16.
[0026]
Here, when a negative DC bias higher than -100 V is applied to the rod-shaped target 16, negative ion particles (electrons) in a partial region of the plasma phase close to the rod-shaped surface charged to the negative potential are directed toward the inside of the plasma phase. Pushed back, a so-called plasma sheath with a low electron density is formed, which acts as a dielectric in contact with the plasma phase to expand the propagation area of the surface wave, further exciting the plasma phase, and expanding the plasma phase. A synergistic effect of instantaneously enlarging the sheath and further exciting the plasma phase is instantaneously generated, and a uniform and high-density steady state is formed inside the workpiece 20 (cylindrical body) surrounding the rod-shaped target 16 as shown in the figure. A plasma phase 21 is created. As a result, the surface of the rod-shaped target 16 (in this case, a copper rod) is strongly impacted by the plasma particles, and metal atoms Cu are scattered (sputtered). The scattered atomic vapor of Cu adheres to the inner wall of the material to be processed 20 (tubular body) and is formed in a short time.
[0027]
Such a film forming process of the inner surface of the cylinder according to the present invention has good reproducibility, and the throughput thereof is as high as 10 times that when the inner surface of the cylinder having the same shape and dimensions is processed by the conventional method. This is because it is generally difficult to generate plasma in a cylindrical body. Conventionally, for example, in the case of a metal wire heater target system along the axis, it takes time to excite the plasma and there is a risk of disconnection. This is because the present invention has completely solved the problem that the plasma generation can be performed only in a short localized range, so that the ECR resonance points must be sequentially moved along the axis.
[0028]
In the initial ignition of the plasma processing described above, the partial surface wave excitation method using the dielectric window 15 is used. However, the excitation AC voltage having an appropriate voltage and frequency is superimposed on the rod-like target 16 by the power supply 18 together with a negative bias. Alternatively, a method of approaching and validating the ECR excitation magnet array 19 may be used. The plasma processing described above is an example in which a copper coating is formed on the inner surface of the ceramic cylinder in this case.However, the inner hardening processing of another cylindrical material with another metal target, for example, the target is titanium, and the plasma processing is performed. By using nitrogen as a generating gas, a titanium nitride film is formed on the inner surface of a stainless steel tube to improve wear resistance and corrosion resistance, or DLC (diamond-like) on a cylindrical inner surface by a carbon rod target is used. Coating) processing can be performed in this manner, etc.
[0029]
FIG. 4 is a sectional view and an electrical connection diagram of a main part of a basic structure according to the second embodiment. In FIG. 4, portions denoted by the same reference numerals as the portions shown in FIG. 3 are the same functional portions, and description thereof will be omitted. In the second embodiment, the shape and the positional relationship between the target and the workpiece in FIG. 3 are reversed, and a bar-shaped workpiece 26 is disposed at the center by an appropriate method so as to surround the workpiece. A cylindrical target 30 made of a conductor supported on an insulating base material 27 is arranged. In this case, the microwave supply port 12a of the waveguide 12 has a relatively large coaxial aperture 12d, and a dielectric window 15 'is fitted in the distal end opening to the full diameter. In this case, the partial surface wave for initial ignition propagates and stands along the entire back surface (surface in contact with the inside of the vacuum vessel) of the dielectric window 15 ′, approaches the upper end of the cylindrical target 30, and has a negative bias. Sufficient interaction with the initial sheath on the target surface (interaction between the sheath and the plasma phase via surface waves) is exhibited.
[0030]
The second embodiment is as described above. Since the relationship between the target and the material to be processed is reversed from that of the first embodiment, the cylindrical target 26 A similar sputtering deposition can be performed with the scattered atomic vapors from 30. Other modified embodiments are possible, as in the first embodiment.
[0031]
FIG. 5 is a sectional view and an electrical connection diagram of a main part of a basic structure according to the third embodiment. In FIG. 5, portions denoted by the same reference numerals as the portions shown in FIG. 3 are the same functional portions, and description thereof will be omitted. In the third embodiment, a rod-shaped target 16 ′ itself similar to the rod-shaped target 16 of FIG. 3 is suspended and supported within the vacuum vessel 11 as a material to be processed for ion implantation. There is no surrounding tubular body. In this example, utilizing the absence of a cylindrical body, a magnetic field (typically, a magnetic field due to an alternating arrangement of annular N / S poles) generating means 29 for confining plasma acting directly on the plasma phase 21 is desired. Is installed along the outer peripheral wall of the vacuum vessel 11 according to The magnetic field generating means 29 may be either a permanent magnet or an electromagnet, and can be used not only for confining the plasma phase but also for initial ignition of plasma plasma.
[0032]
In the third embodiment, the plasma is excited and generated in the same manner as in the first embodiment, so that the ion particles in the plasma phase are implanted into the surface of the target 16 ', thereby forming a desired impurity layer. be able to. The type of plasma generation gas and the pressure in the container 11 are selected according to the impurity layer to be formed and the surface structure.
[0033]
FIG. 6 is a sectional view and an electrical connection diagram of a main part of a basic structure according to the fourth embodiment. In FIG. 6, portions denoted by the same reference numerals as the portions shown in FIG. 4 are the same functional portions, and description thereof will be omitted. In the fourth embodiment, a rod-shaped target 30 ′ itself similar to the cylindrical target 30 of FIG. 4 is suspended and supported within the vacuum vessel 11 as a material to be processed for ion implantation, and the target 16 ′ is formed. Is not present.
[0034]
Also in the fourth embodiment, since the plasma is excited and generated in the same manner as in the second embodiment (FIG. 4), ion particles in the plasma phase are implanted into the inner surface of the target 30 ', and Can be formed. The type of plasma generation gas and the pressure in the container 11 are selected according to the impurity layer to be formed and the surface structure.
[0035]
FIG. 7 is a sectional view and an electrical connection diagram of a main part of a basic structure according to a fifth embodiment. This embodiment differs from the chamber type shown in FIGS. 3 to 6 in that it is a portable device that performs plasma processing using plasma generated in the atmosphere without using a chamber. It can be considered that the vacuum vessel 11 is removed from the first embodiment (FIG. 3). Therefore, the portions denoted by the same reference numerals as those shown in FIG. 3 are the same functional portions, and the description thereof will be omitted. However, the dielectric 15 ″ at the center of the distal end of the microwave supply port 12a is made small enough to be held by the coaxial cylindrical conductor 12c, and the rod-shaped target 36 made of a conductor is screwed to the dielectric 15 ″ (not shown). ) And is sufficiently firmly held by an appropriate method such as) to protrude from the microwave supply port 12a.
[0036]
In the fifth embodiment, when microwaves are emitted from the microwave supply port 12a of the waveguide 12 and an appropriate negative bias voltage is applied to the rod-shaped target 36 (through an appropriate initial plasma phase ignition process). A stationary plasma phase 21 is generated around the rod-shaped target 36. In this example, a part of an installed machine or the like that cannot be accommodated in a vacuum vessel, or a workable material 37 that is desired to be plasma-processed on the target-facing surface in the atmosphere even in a single body that can be accommodated is guided. A rod-shaped target 36 projecting from the tube 12 is fixed in a positional relationship shown in FIG. Therefore, on the concave surface facing the target surface of the material to be processed 37, the target material can be subjected to vapor deposition and surface modification by plasma sputtering.
[0037]
The target material can be selected variously according to the mating material and the processing purpose. In some cases, the work position is covered with a container 38 applicable as a plasma chamber later, and the flow of the plasma generation gas and the pressure adjustment are performed. You may do so. Further, the shape of the target 36 of the portable device is not limited to the rod shape shown in the figure, and may be various shapes such as a spherical shape, a three-dimensional shape, a cone or a pyramid shape, a flat plate shape, and a truncated cone shape according to the contour shape of the processing surface. can do.
[0038]
The embodiment shown in FIG. 8 and FIG. 9 is an apparatus using a target made of a flat conductor, unlike the conventional target / workpiece coaxial arrangement type apparatus. The material to be processed is also formed on the front side of the target. Since it is effectively processed by the plasma phase, it is arranged to face the target plate. Also in these figures, the portions using the same reference numerals as those already described are the same functional portions, and thus the overlapping description will be omitted. In these figures, the thickness of the wall of the vacuum vessel is omitted for simplification.
[0039]
In the sixth embodiment shown in FIG. 8, the microwave supply ports 12a ′ and 12a ″ of the waveguide 12 are formed by slits formed on one side (lower side in the figure) of the tube tip. In order to obtain a standing wave, they are arranged in parallel at a pitch of an integral multiple of the microwave wavelength.Dielectric windows 15a and 15b are attached to microwave supply ports 12a 'and 12a "on the side of the waveguide 12, and a vacuum container is provided. The insulating plate 31 applied to the upper end surface of the substrate 11 and the target plate 32 on which the insulating plate 31 is mounted are also formed with slits connected to the microwave supply ports 12a 'and 12a ". The target plate 33 has a width slightly larger than the interval between the microwave supply ports 12a ′ and 12a ″ as an effective processing width and has a depth corresponding to the target plate 32. 32.
[0040]
Also in the sixth embodiment, when microwaves are emitted from the microwave supply port 12a of the waveguide 12 and an appropriate negative bias voltage is applied to the target plate 32 (via an appropriate initial plasma phase ignition process). In the lower space of the target plate 32, the stationary plasma phase 21 is generated via the expanded sheath layer. Thus, on the upper surface of the processing target plate 33 facing the target surface, vapor deposition of the target material by plasma sputtering and surface modification can be performed.
[0041]
In the seventh embodiment shown in FIG. 9, the microwave supply port of the waveguide 12 is formed by the dielectric window 15 'itself attached to the opening at the distal end. The dielectric window 15 ′ is arranged so as to look into the inside of the vacuum container 11 from the upper end of the side wall of the vacuum container 11, and a conductive target plate 34 is provided on a main portion of the ceiling wall of the vacuum container 11 via an insulator 35. Supported and facing into the chamber. The target plate 33 is defined as an effective processing area by a size within the projection area of the target plate 34, and is arranged to face the target plate 34 by appropriate means.
[0042]
Also in the seventh embodiment, when microwaves are emitted from the microwave supply port of the waveguide 12 and an appropriate negative bias voltage is applied to the target plate 34 (via an appropriate initial plasma phase ignition process), The stationary plasma phase 21 is generated in the space below the target plate 34 via the enlarged sheath layer. Thus, on the upper surface of the processing target plate 33 facing the target surface, vapor deposition of the target material by plasma sputtering and surface modification can be performed.
[0043]
In the apparatus configuration according to the above-described seventh embodiment, even when the processing target plate 33 is not disposed, the plasma is similarly excited and generated, so that the ion particles in the plasma phase are implanted into the inner surface of the target plate 34. Thus, a desired impurity layer can be formed. The type of plasma generation gas and the pressure in the container 11 are selected according to the impurity layer to be formed and the surface structure.
[0044]
【The invention's effect】
As described above, according to the present invention, by generating a surface wave excited plasma phenomenon without a dielectric material in the vicinity of a target made of a conductor, a material to be processed basically corresponding to the target shape is sputtered or sputtered. A plasma generation method and apparatus suitable for performing plasma processing such as ion implantation are provided.
In particular, the present invention makes it possible to generate high-density plasma in a cylindrical space, which has been difficult when performing inner surface processing of a tube or surface processing of a rod-shaped body with plasma, at a relatively low cost. It is apparent that the present invention provides a method and an apparatus for generating a surface wave excited plasma near a conductor target. In addition, a relatively large-diameter conductive cylindrical target having an inner surface as a target surface is prepared, and a tubular material, not a rod-shaped body, is disposed inside the target. First, the outer surface of the material is plasma-processed. By arranging the material around the rod-shaped target, the inner surface thereof can be subjected to the same plasma processing, and the industrial use value thereof is extremely large.
[Brief description of the drawings]
FIG. 1 shows a state (A) in which a microwavelength surface wave propagates at an interface between a dielectric and a plasma phase in the prior art to further excite and regenerate plasma, and is formed in the present invention so as to face a conductor target. It is a figure which shows typically the state (B) in which the surface wave of a microwave propagates to the interface of a plasma sheath and a main body plasma phase, and further excites and reproduces plasma.
FIG. 2 is a schematic diagram (A) of an experimental device for proving the principle of the present invention, in which a surface wave is standing inside a quartz window without applying a bias voltage to a target metal rod in the experimental device. A schematic diagram (B) of a state in which plasma is excited and emitted in the periphery, and a state in which a plasma phase is generated along the entire length of a target metal rod to which a negatively biased voltage is applied by using the plasma excited and emitted in the vicinity of the quartz window as a pilot light. It is a schematic diagram (C).
FIG. 3 is a longitudinal sectional view and an electrical connection diagram of a device section showing a first embodiment of the device of the present invention.
FIG. 4 is a longitudinal sectional view and an electrical connection diagram of a device section showing a second embodiment of the device of the present invention.
FIG. 5 is a longitudinal sectional view and an electrical connection diagram of a device section showing a third embodiment of the device of the present invention.
FIG. 6 is a longitudinal sectional view and an electrical connection diagram of a device section showing a fourth embodiment of the device of the present invention.
FIG. 7 is a longitudinal sectional view and an electrical connection diagram of a device section showing a fifth embodiment of the device of the present invention.
FIG. 8 is a longitudinal sectional view and an electrical connection diagram of a device section showing a sixth embodiment of the device of the present invention.
FIG. 9 is a longitudinal sectional view and an electrical connection diagram of a device section showing a seventh embodiment of the device of the present invention.
[Explanation of symbols]
11 Vacuum container (chamber)
12 Waveguide
13 Microwave oscillator
14 Drive power supply
15 Dielectric plate
16, 36 Bar target
17 Lower insulating plate
18 bias power supply
19 ECR magnet array
20 Work material (tubular)
21 Plasma phase
26 Work material (rod shape)
27 Insulating base material
30 cylindrical target
31 Insulating board
32, 34 Target plate
33 Work plate
35 Insulator

Claims (13)

A target made of a conductor is arranged so that at least one end thereof is close to the microwave supply port, an initial plasma phase is generated close to the surface of the target, microwaves are emitted from the microwave supply port, and By applying a negative bias voltage to the target, the sheath region having a low electron density generated near the target surface in opposition to the plasma phase is enlarged, and the emitted microwave is mixed with the sheath region and the plasma phase. A method for generating surface wave excited plasma, wherein the target is made to function as a surface wave antenna by generating a surface wave excited plasma by propagating from one end to the other end along a boundary. A dielectric is interposed in the microwave supply port, and the microwave emitted from the microwave supply port acts on the dielectric to propagate as a surface wave on a dielectric surface close to the target surface. 2. The method according to claim 1, wherein a plasma phase comprising a surface wave excited plasma is initially generated in the region. A plasma chamber having a gas inlet for plasma generation and an exhaust port, and a plasma chamber connected to the microwave supply port is provided, and the target is disposed in the chamber so that at least one end thereof is close to the microwave supply port. 3. The method according to claim 1, wherein the method is performed. A waveguide that guides microwaves, a target made of a conductor protruded by being electrically insulated from the end of the waveguide, and a power supply for applying a negative bias voltage to the target, Microwave propagation along the sheath region with a low electron density formed according to the magnitude of the bias voltage around the target generates surface wave excited plasma, and the surface of the workpiece facing the target surface An apparatus for generating surface-wave-excited plasma, characterized in that it is configured to perform plasma processing. A plasma chamber having a plasma generation gas inlet, an exhaust port, and a microwave supply port; a target made of a conductor disposed so that at least one end thereof is close to the microwave supply port in the chamber; A dielectric window arranged to substantially cross the wave supply port, a means for initially generating a plasma phase in proximity to the surface of the target, and the initial generation by applying a negative bias voltage to the target. A bias power supply for enlarging the low electron density sheath region between the plasma phase and the target surface. The surface wave excited plasma at the interface between the plasma phase and the low electron density sheath region causes the target itself or the plasma phase to expand. The surface of the material to be processed when placed in contact with Surface wave excited plasma generator, characterized in that. The means for initially generating the plasma phase in the chamber causes the microwave emitted from the microwave supply port to act on the dielectric window, and causes the surface of the dielectric window on the side close to the surface of the target to generate a surface wave. 6. The apparatus according to claim 5, further comprising a mechanism for transmitting the surface wave and generating a surface wave excited plasma in the adjacent region. 6. The apparatus of claim 5, wherein the means for initially generating the plasma phase in the chamber comprises circuit means for superimposing an AC voltage for ignition discharge on the negative bias voltage in the bias power supply. 8. The apparatus according to claim 7, wherein said circuit means superposes an AC voltage for promoting plasma discharge on said negative bias voltage even after said ignition discharge. The means for initially generating the plasma phase in the chamber comprises a magnetic field generating means surrounding the chamber and comprising a permanent magnet or an electromagnet for magnetically exciting at least a region close to the dielectric window. An apparatus according to claim 5, characterized in that: The apparatus according to any one of claims 5 to 9, further comprising a magnetic field generating means for generating a magnetic field for confining plasma surrounding the inside of the peripheral wall of the chamber after the generation of the plasma phase. The apparatus according to any one of claims 5 to 10, wherein the target is a rod-shaped body, and the introduced microwave is propagated along an outer peripheral surface of the target. The apparatus according to any one of claims 5 to 10, wherein the target is a cylindrical body, and the introduced microwave is propagated along an inner peripheral surface of the target. The said target is made into a plate-shaped body, The said introduced microwave was made to propagate along the surface which went into the chamber of the said target metal, The Claims any one of Claims 5-10 characterized by the above-mentioned. Equipment.

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