JP2008281346A - Atomic beam source and surface reforming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a substrate processing state in real time by imparting versatility easily coping in the case of different using conditions, and by changing an electron beam distribution during beam irradiation. <P>SOLUTION: Two rod-shaped electrodes 2 used as anodes are arranged inside a discharge container 1 serving as a cathode, and a DC power source 6 is connected to the electrodes 2, and a voltage is applied. Structure is adopted wherein one rod-shaped insulator 3 is arranged between the two electrodes 2, and the insulator 3 can be moved vertically and horizontally by an insulator driving part 20. Further, the discharge container 1 is provided with a gas supply port 4 for introducing gas necessary for generating plasma in the container, and a beam discharge hole 5 which is a discharge part for discharging the atomic beam. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an atomic beam source that generates an atomic beam (electron beam) for performing dry etching, surface cleaning, etc., for example, in a semiconductor manufacturing process and the like, and in particular, uniformity of processing speed in an irradiation range is required. The present invention relates to an atomic beam source suitable for such a case, and a surface modification apparatus using the atomic beam source.

  In a conventional atomic beam generator, in order to obtain a uniform processing speed within the substrate to be processed, the substrate to be processed is rotated, a method for optimizing the distribution and diameter of the emission holes of the beam, or emission. There has been a method of optimizing by changing the thickness of the portion where the hole is provided.

  FIG. 12 is a diagram illustrating a configuration example of a conventional atomic beam source described in Patent Document 1. In FIG.

  In FIG. 12, 101 is a gas nozzle, 102 is a DC power source, 103 is a beam emission electrode, 104 is an atomic beam, 105 is an anode, 108a to 108c are beam emission holes, 109 is a sample, and 110 is a turntable.

  FIG. 13 is a diagram showing another configuration example of the conventional atomic beam source described in Patent Document 2. In FIG. (A) is the perspective view which carried out the partial cross section, (b) is sectional drawing of a discharge electrode.

13A and 13B, 210 is a plasma space, 212 is a discharge vessel, 214 is a gas introduction port, 216 is a gas introduction electrode, 218 is an atomic beam emission hole, 220 is an emission electrode, 222 is an electrode, 224 Indicates a gas introduction pipe, and 228 indicates a DC power source.
JP-A-8-255698 JP-A-10-106798

  However, in the conventional configuration described in Patent Documents 1 and 2, when the usage conditions are different, such as changing the distance, angle, etc. between the atomic beam and the substrate to be processed, or attaching to a different apparatus, It is necessary to re-optimize the distribution, hole diameter, and thickness of the electron beam emission holes. For this reason, it is necessary to newly create an emission hole electrode provided with the emission holes. Therefore, there has been a problem that it takes cost and time to equalize the processing of the substrate to be processed.

  Further, it is difficult to change the distribution, hole diameter, and thickness of the emission holes while the substrate is irradiated with the beam. For this reason, there has been a problem that the electron beam distribution cannot be changed during beam irradiation.

  The present invention solves the above-mentioned conventional problems, provides versatility that can easily cope with different use conditions, and changes the electron beam distribution during beam irradiation, thereby processing the substrate in real time. An object of the present invention is to provide an atomic beam source and a surface modification apparatus capable of controlling the state.

  In order to achieve the above object, the invention according to claim 1 is characterized in that a cylindrical body that acts as a cathode to generate plasma and emits ions or atoms, and one of the cylindrical bodies. An emission part that is opened in the part and emits the ions or atoms to the outside, an anode disposed inside the cylindrical body, and the emission part and the anode are electrically connected to each other, and a voltage is applied. A power source for generating the plasma in the cylindrical body and an insulator disposed inside the cylindrical body are provided.

  According to a second aspect of the present invention, in the atomic beam source according to the first aspect of the present invention, an insulator driving unit that displaces the insulator with respect to the emitting unit inside the cylindrical body is provided.

  According to a third aspect of the present invention, in the atomic beam source according to the first or second aspect, the distances from any two end faces of the anode to the center of the insulator are set to the same distance. .

  According to a fourth aspect of the present invention, in the atomic beam source according to any one of the first to third aspects, the anode is a ring-shaped electrode or two rod-shaped anodes.

  The invention according to claim 5 is the atomic beam source according to any one of claims 1 to 4, characterized in that the shape of the insulator is symmetrical to the center line of the insulator.

  According to a sixth aspect of the present invention, there is provided a surface modification apparatus for performing surface modification of an object by emitting ions or atoms to the object from an atomic beam source that generates plasma inside the cylindrical body. The atomic beam source according to any one of claims 1 to 5 is used as a source, and an emission central axis for emitting ions or atoms of the electron beam source is set to an axis perpendicular to a plane on which the object is placed. It is characterized by being installed at an arbitrary angle.

  According to the present invention, it is possible to easily cope with different usage conditions such as changing the distance, angle, etc. between the atomic beam and the substrate to be processed, or by attaching to a different apparatus. By changing the line distribution, the processing state of the substrate can be controlled in real time.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an embodiment of an atomic beam source according to the present invention, where (a) is a perspective view and (b) is a sectional view.

  In the atomic beam source 10 of Embodiment 1 of FIG. 1, two rod-shaped electrodes 2 serving as anodes are disposed inside a discharge vessel 1 serving as a cathode that is a rectangular parallelepiped cylindrical body. It is connected to a DC power source 6 so that a voltage can be applied. In addition, one rod-like insulator 3 is disposed between the two electrodes 2, and as indicated by an arrow in the figure, an insulator drive unit (described later in detail) 20 causes the insulator 3. Can be moved up, down, left and right. Further, the discharge vessel 1 is provided with a gas supply port 4 for introducing a gas necessary for generating plasma in the vessel, and a beam emission hole 5 which is an emission part for emitting an electron beam.

  In this example, the outer peripheral shape of the discharge vessel 1 is a rectangular parallelepiped cylindrical body, but may be any shape such as a cylinder, a cube, a sphere, or a polyhedron as shown in FIG. The discharge vessel 1 is formed of a conductor such as stainless steel or aluminum, and generates a plasma by applying a voltage between the electrode 2 and the discharge vessel 1 is generally grounded. In order to prevent the discharge vessel 1 from being scraped by plasma generated inside, it is preferable to use a material having a low sputtering rate, such as carbon, on the inner surface of the vessel.

  As for the electrode 2, two cylindrical ones are arranged in this example, but the cross-sectional shape may be any cylindrical shape such as a square or a polygon. For example, in the case of a cylindrical discharge vessel 1 such as a modification of the atomic beam source of the present embodiment shown in FIG. 2 (members corresponding to those shown in FIG. 1 are given the same reference numerals and description thereof is omitted). The electrode 2 has a ring shape. As the material of the electrode 2, carbon or the like may be used as in the inside of the discharge vessel 1 in the first embodiment. Furthermore, the shape of the electrode 2 is not limited to a rod shape as shown in FIG. 1 or a ring shape as shown in FIG. 2, but may be a polygonal or plate-like electrode having a plurality of holes of arbitrary shapes. Good.

  FIGS. 3A and 3B are explanatory views showing the configuration of an embodiment of the surface modification apparatus according to the present invention. In this example, the atomic beam source 10 having the configuration shown in FIG. 1 is used.

  In FIG. 3, the emission central axis M for emitting ions or the atomic beam 11 in the atomic beam source 10 is an axis N perpendicular to the mounting plane of the substrate holder 9 on which the substrate 8 that is the object of surface modification is mounted. On the other hand, it can be installed at an arbitrary angle θ.

  Therefore, when the electron beam 11 is irradiated from the atomic beam source 10 to the substrate 8, the atomic beam 11 is made to be perpendicular to the surface of the substrate 8 as shown in FIG. As shown in FIG. 3B, irradiation may be performed with an arbitrary angle θ. In FIG. 3B, the electrode 2 and the insulator 3 of the atomic beam source 10 are arranged so as to be parallel to the surface of the substrate 8, but the electrode 2 and the insulator 3 are parallel to the surface of the substrate 8. The arrangement may be such that it does not become.

  FIG. 4 is an explanatory diagram of the principle of operation of the atomic beam in the present atomic beam source 10. In order to operate the atomic beam, first, components other than the DC power source 6 are placed in the vacuum vessel 1 and exhausted sufficiently. After that, gas (argon in this example) is introduced from the gas supply port 4. Here, a voltage is applied between the electrode 2 and the discharge vessel 1 by a DC power source 6 installed outside the vacuum vessel 1. As a result, a discharge is generated between the electrode 2 and the discharge vessel 1 to generate plasma, and argon ions and electrons are generated.

  In the configuration as shown in FIG. 4, the electrons generated near the center act almost symmetrically with the attractive force from the two electrodes (anode) 2 and the repulsive force from the discharge vessel (cathode) 1. The reciprocating motion is repeated in the vertical direction, and a portion with a large electron density is formed above and below the center. Atoms generated outside the vicinity of the center are attracted to the electrode (anode) 2 by the attractive force of the electrode 2 and the repulsive force from the discharge vessel.

  Further, argon ions are accelerated upward or downward by repulsive force from the electrode (anode) 2 and attractive force from the discharge vessel (cathode) 1 near the center, and ions accelerated toward the beam emitting hole 5 are accelerated. In front of the beam emission hole 5 or in the beam emission hole 5, it collides with electrons and recombines to become neutral atoms. In the collision between ions and electrons, the mass of the electrons is negligibly small compared to the ions, so that the kinetic energy of the argon ions is directly transferred to the atoms and a high-speed atomic beam is emitted. Other ions are attracted to the discharge vessel (cathode) 1 or collide with electrons to become neutral atoms.

  Because of this principle of operation, the density of argon ions and accelerated argon atoms increases on the surface, line, or point that are equidistant from the two electrodes 2, and the intensity of the electron beam increases accordingly. It has a structure. Even in the case where the electrode is not two bars but is a plate having a hole, the same applies to surfaces, lines, and points equidistant from each part of the electrode 2. Therefore, the arrangement of the insulator 3 in the position having such a positional relationship has a great influence on the plasma state in the discharge vessel 1, and the distribution of the electron beam emitted from the discharge vessel 1 and the uniformity of the substrate processing are reduced. It is effective to control.

  In addition, because of the structure described above, the plasma and electron beam distributions are symmetric with respect to surfaces, lines, and points that are equidistant from the electrode 2, so that the uniformity of the emitted electron beam distribution, that is, the substrate processing In order to improve the uniformity, the shape of the insulator 3 is preferably symmetric with respect to this plane, line, and point. Furthermore, the number of insulators 3 is not necessarily one, and a plurality of insulators 3 may be arranged symmetrically with respect to planes, lines, and points that are equidistant from the electrode 2.

  As for the insulator 3, an example of a cylindrical shape is shown in FIG. 1, but any shape such as a disk shape as shown in FIG. 2 may be used.

  FIGS. 5A to 5H are cross-sectional views of an atomic beam source showing examples of various shapes of the insulator 3 in the case where the electrode 2 is in the shape of two rods, and the cross-sectional shape is the square shown in FIG. Polygon, ellipse shown in (b), cross shown in (c), rhombus shown in (d), ring shown in (e), free curve shown in (f), multiples shown in (g) and (h) Anything such as a circular shape may be used.

  6A to 6D are diagrams showing examples of various shapes of the insulator 3 when the electrode 2 is not rod-shaped, and the electrode 2 is ring-shaped as shown in FIGS. The insulator 3 can be spherical or rod-shaped (the cross section has an arbitrary shape), or any shape that is axially symmetric with respect to the central axis. As shown in FIG. The same applies to the shape in which is formed.

  Further, as shown in (d), in the case where a plurality of holes 2a are formed in the plate-like electrode 2, the insulator 3 having any shape that is spherical, rod-shaped, or axially symmetric with respect to each hole 2a. Place. Thus, when there are a plurality of holes 2a in the electrode 2, it is not necessary to arrange the insulators 3 in all the holes 2a, and it may be arranged only in a part of the holes 2a.

  The insulator 3 is preferably made of ceramic such as alumina because it may be at a high temperature.

  FIG. 7 is a cross-sectional view showing the structure of the insulator, and the cross-sections shown in (a) and (b) are solid bodies of a circle or quadrangle and the whole is the insulator 3, or (c) and (d). As shown, a film of the insulator 3 formed on the surface of the conductor 21, or a film of the insulator 3 formed on the surface of the hollow conductor 21, as shown in (e) and (f). Alternatively, as shown in (g) and (h), the same effect can be obtained by forming the insulator 3 film on the inner and outer peripheries of the hollow conductor 21.

  In addition, as shown in FIG. 1 and FIG. 2, the beam emission hole 5 only needs to have a substantially uniform hole portion. Other shapes may also be used.

  FIGS. 8A to 8D are explanatory views of the positional displacement of the insulator 3 in the atomic beam source having the configuration shown in FIG. 1, and FIG. 9 is a diagram when the insulator is at the positions shown in FIGS. 8A to 8D. It is an actual measurement figure of intensity distribution of the beam emitted from the atomic beam.

  8A shows a case where there is no insulator, FIG. 8B shows a case where the insulator 3 is arranged at the center, and FIG. 8C shows a case where the insulator 3 is arranged at the lower part (on the beam emission hole 5 side). (D) shows the case where the insulator 3 is arranged on the upper side.

  When an atomic beam is irradiated perpendicularly to the surface of the substrate that is the electron beam irradiation target, the intensity distribution of this beam coincides with the distribution of the processing speed by the atomic beam (for example, the processing speed of the substrate surface). . In the following, the relationship between the distribution of the processing speed of the substrate and the position of the insulator will be described, but the same applies to the intensity distribution of the atomic beam.

  As shown in FIG. 9, in the case of FIG. 8A without the insulator 3, the processing speed at the center is increased, whereas the insulator 3 is arranged at the center of the two electrodes 2. In the case of 8 (b), it becomes uniform as a whole. Further, when the insulator 3 is moved to the beam emission hole 5 side as shown in FIG. 8 (c), the distribution is such that two peaks are formed with the center as the axis of symmetry, as shown in FIG. 8 (d). When the insulator 3 is moved away from the discharge hole 5, the central processing speed becomes very high.

  By changing the position of the insulator 3 in this way, the processing speed distribution can be changed. Here, an example in which the insulator 3 is moved in the vertical direction has been described, but the distribution of the processing speed can be changed also when the insulator 3 is moved in the left and right directions.

  Furthermore, the uniformity of the processing speed can be further improved by measuring the film thickness on the substrate being processed in real time, feeding back the result, and moving the position of the insulator 3 as described above. Can do.

  For example, in the configuration of the atomic beam source as shown in FIG. 1, when it is desired to increase the processing speed of the outer peripheral portion of the substrate to be processed, the insulator 3 is placed on the beam emission hole 5 side as shown in FIG. Move to. Conversely, when it is desired to increase the processing speed at the center of the substrate, it can be controlled by moving the insulator 3 in a direction away from the beam emission hole 5 as shown in FIG. Further, when it is desired not only to uniformly treat the substrate but also to process the surface of the substrate, the insulator 3 can be moved during the treatment.

  10A and 10B are diagrams showing a configuration example of an insulator driving unit applied to the present embodiment, in which FIG. 10A is a front sectional view, and FIG. 10B is a sectional view taken along line XX in FIG.

  In FIG. 10, the insulator driving unit 20 is configured to fix the columnar insulator 3 with a bolt 24 or the like so as to be movable up and down within the range of the long hole 23 provided in the discharge vessel 1. A portion (a portion not covered with the head of the bolt 24) that is open to the outside in the case can be closed with a covering plate (not shown) or the like.

  With this configuration, the substrate processing speed distribution can be changed by changing the device for attaching the atomic beam source, changing the atomic beam mounting position, or changing the substrate processing speed distribution by the atomic beam for each substrate. When there is no need to change during irradiation, the position of the insulator 3 can be moved within the range of the long hole 23 provided in the discharge vessel 1.

  In the configuration shown in FIG. 10, the insulator 3 may be fixed to other portions such as the electrode 2 instead of the discharge vessel 1. In addition to the simple long hole 23, depending on the range in which the insulator 3 is to be moved, the hole shape is adapted to that.

  11A and 11B are diagrams showing another configuration example of the insulator driving unit applied to the present embodiment, in which FIG. 11A is a front sectional view and FIG. 11B is a sectional view taken along line XX in FIG.

  In FIG. 11, when it is necessary to move the insulator 3 during the atomic beam irradiation, the insulator drive unit 20 uses, for example, the power of the motor 25 to the shaft 28 connected to the ball screw 26 and the guide 27. The position of the insulator 3 can be moved by transmitting to the insulator 3 via the control, and the distribution of the processing speed of the substrate can be controlled as described above.

  At this time, a bellows 29 is used in this example in order to prevent gas leakage from the gap between the moving shaft 28 and the discharge vessel 1. In addition to the bellows 29, a sealing method using a magnet coupling or an O-ring may be used.

  If the motor 25, the ball screw 26, the guide 27, and the like have a structure that can be used in a vacuum, the entire structure as shown in FIG. However, if the motor 25, the ball screw 26, the guide 27, and the like cannot be used in a vacuum, an appropriate distance between the surface indicated by Y in FIG. 11 and the wall of the vacuum vessel 1 on which the atomic beam is installed. By sealing, the motor 25, the ball screw 26, the guide 27 and the like can be arranged in the atmosphere, and can be realized with the configuration as shown in FIG.

  In addition to the above configuration example, a configuration in which the insulator is moved by various mechanisms can be realized.

  The present invention can easily cope with different usage conditions, such as changing the distance and angle between the atomic beam and the substrate to be processed, or being attached to a different apparatus. By changing the distribution, the processing state of the substrate to be processed can be controlled in real time. In the semiconductor manufacturing process, etc., the uniformity of the processing speed in the irradiation range or the control of the processing speed distribution can be controlled. It can be used when required.

It is a figure which shows schematic structure of embodiment of the atomic beam source which concerns on this invention, (a) is a perspective view, (b) is sectional drawing. The perspective view which shows the cylindrical discharge vessel which is a modification of this embodiment partially in cross section (A), (b) is explanatory drawing which shows the structure of embodiment of the surface modification apparatus which concerns on this invention. Explanatory drawing of the principle of operation of the atomic beam in the atomic beam source of this embodiment (A)-(h) is sectional drawing of the atomic beam source which shows the example of various shapes of an insulator in case the electrode of this embodiment is two rod shape (A)-(d) is a figure which shows the example of various shapes of the insulator in case the electrode of this embodiment is not rod-shaped, (a), (b) is a perspective view, (c), (d) is the top Figure is a plan view (A)-(h) is sectional drawing which shows the structure of the insulator of this embodiment. (A)-(d) is explanatory drawing of the position displacement of the insulator in the atomic beam source of this embodiment. 8A to 8D are actual measurement diagrams of the intensity distribution of the beam emitted from the atomic beam. It is a figure which shows the structural example of the insulator drive part applied to this embodiment, (a) is front sectional drawing, (b) is XX sectional drawing in (a). It is a figure which shows the other structural example of the insulator drive part applied to this embodiment, (a) is front sectional drawing, (b) is XX sectional drawing in (a). Diagram showing a configuration example of a conventional atomic beam source The figure which shows the other structural example of the conventional atomic beam source

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge vessel 2 Electrode 3 Insulator 4 Gas supply port 5 Beam emission hole 6 DC power supply 8 Substrate 9 Substrate holder 10 Atomic beam source 11 Atomic beam 20 Insulator driving part 21 Conductor 23 Long hole 24 Bolt 25 Motor 26 Ball screw 27 Guide 28 Shaft 29 Bellows

Claims (6)

A cylindrical body that acts as a cathode, generates plasma inside, and emits ions or atoms;
An emission part that is opened in a part of the cylindrical body and emits the ions or atoms to the outside;
An anode disposed inside the cylindrical body;
A power source electrically connected to the emitting portion and the anode, and applying a voltage to generate the plasma in the cylindrical body;
An insulator disposed inside the cylindrical body;
An atomic beam source characterized by comprising:   The atomic beam source according to claim 1, further comprising an insulator driving unit that displaces the insulator with respect to the emitting unit inside the cylindrical body.   3. The atomic beam source according to claim 1, wherein the distances from any two end faces of the anode to the center of the insulator are set to the same distance.   The atomic beam source according to claim 1, wherein the anode is a ring-shaped electrode or two rod-shaped anodes.   The atomic beam source according to claim 1, wherein the shape of the insulator is symmetrical with respect to a center line of the insulator. In a surface modification apparatus for performing surface modification of an object by discharging ions or atoms to the object from an atomic beam source that generates plasma inside the cylindrical body,
The atomic beam source according to any one of claims 1 to 5 is used as the electron beam source, and an emission central axis for emitting ions or atoms of the electron beam source is perpendicular to a mounting plane of the object. A surface modification apparatus characterized by being installed at an arbitrary angle with respect to an axis.

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