JP2009043613A - Pulsed electron beam generating device, and pulsed electron beam film deposition device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pulsed electron beam generating device capable of continuously generating a large number of electron beam pulses, and an electron beam film deposition device using the above device. <P>SOLUTION: In this pulsed electron beam generating device 8 equipped with a pulsed electron beam generating part 8a to generate pulsed electron beams, and a guide tube 8b forming a hollow tube made of an insulating material, which is connected to the pulsed electron beam generating part 8a to guide the generated electron beam to a target surface, a cylindrical structure 8c for coating a part of the side of the guide tube is mounted to the guide tube with a gap provided between itself and the surface of the guide tube 8b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a pulsed electron beam generator capable of stably generating a pulsed electron beam and a film forming apparatus using the pulsed electron beam generator.

  In the pulsed electron beam deposition method (PED method), a part of the target surface is ablated by irradiating a pulsed electron beam onto the surface of the target placed opposite to the substrate, and the plasma generated thereby. In this method, a film made of the same material as the target is formed on the substrate by attaching a flow to the substrate. This method uses a pulsed electron beam capable of obtaining a high power density, unlike a normal electron beam vapor deposition method using a continuous electron beam for target abrasion. Therefore, ablation can be performed without largely depending on the thermodynamic characteristics such as the melting point or specific heat of the target material, and this is a particularly useful film forming method when the target material is a composite material. In addition, the future is expected to provide a useful means in the development of nanocomposite materials.

  The pulsed electron beam deposition method has been proposed in theory for a relatively long time. For example, Patent Document 1 discloses a basic structure of a pulsed electron beam generator used in a pulsed electron beam film forming apparatus. In this apparatus, an electron beam taken out by applying an electric field to a plasma source is guided onto a target by a dielectric guide tube to evaporate the target component. The electron beam is bent by a magnet provided in a dielectric guide tube and guided onto the target surface.

  Patent Document 2 describes the principle and configuration of pulsed electron beam generation. In particular, a pulsed electron beam generator improved with the intention of emitting a high-quality electron beam with a high number of firings is disclosed. Note that there is only PEBS-20 manufactured by Neocera as a pulsed electron beam generator currently on the market.

Special table 07-501654 Special table 2005-518637

  As described above, the pulsed electron beam deposition method has been proposed in theory for a relatively long time, but has recently been commercialized as a film forming apparatus. An important cause is that it is difficult to stably drive the pulsed electron beam generator for a long time. If the pulsed electron beam generator stops abnormally during film formation, film formation with a required thickness cannot be performed. Although it depends on the excitation voltage of the pulsed electron beam, in the case of currently available equipment, the equipment is abnormally stopped by firing several hundred to several thousands of pulsed electron beams, resulting in incomplete film formation. finish.

  Therefore, in order to obtain a pulsed electron beam film forming apparatus that can withstand practical use, it is essential to obtain a pulsed electron beam generating apparatus that operates stably for a long time and does not stop abnormally during film formation. Here, operating for a long time means that the total number of pulses that can be continuously emitted is large.

  The present invention has been made in order to solve the above-described problems of the conventional pulsed electron beam generator, and can be stably operated for a long time, and a pulsed electron beam film that can withstand practical use. It is an object to obtain a device.

  In order to solve the above problems, a first pulsed electron beam generator of the present invention comprises a pulsed electron beam generator for generating a pulsed electron beam and a hollow tube made of an insulating material. A pulsed electron beam generating apparatus connected to the pulsed electron beam generating unit and including a guide tube for guiding the generated electron beam to a target surface, and covering at least a part of a side surface of the guide tube The structure is attached with a space from the guide tube surface.

  When film formation is performed using a pulsed electron beam generator, the target material evaporated from the target surface scatters in the direction of the pulsed electron beam generator and adheres to the guide tube provided at the tip of the target material and gradually accumulates. To do. When the target material is conductive, the insulating property of the guide tube is destroyed by the deposition of the target material on the guide tube. When the breakdown of insulation progresses with the progress of deposition, and a conductive path is formed from the tip of the guide tube to the pulsed electron beam generator, the charge that is released from the tip of the guide tube and is directed to the target surface is transferred to the surface of the guide tube. And escapes to the pulsed electron beam generator and the vacuum chamber body. As a result, it is considered that the normal operation of the pulsed electron beam apparatus is impaired and the apparatus is abnormally stopped.

  Further, during the generation of the pulsed electron beam, the guide tube becomes a high temperature, for example, near 300 ° C., and when the target material is easily evaporated such as Mg, the attached target component is easily evaporated again. A low-pressure inert gas atmosphere is indispensable for the generation of the pulsed electron beam. If the partial pressure of the evaporated target component is increased, the generation of the pulsed electron beam is adversely affected.

  However, in the first pulsed electron beam generator of the present invention, at least a part of the guide tube is covered with the cylindrical structure, so that the target component is partially prevented from adhering to the surface of the guide tube during film formation. Thus, a decrease in the insulating properties of the guide tube is suppressed. Moreover, since the cylindrical structure attached to the side surface of the guide tube is thermally separated from the guide tube, the temperature is kept low even during the generation of the pulsed electron beam. Therefore, the target component re-evaporated from the surface of the guide tube contacts the cylindrical structure and is cooled and condensed, so that it does not contribute to an increase in the partial pressure of the target component.

  The first pulsed electron beam generator of the present invention can generate a large number of electron beam pulses continuously for the reasons described above.

  In order to solve the above problems, a second pulsed electron beam generator of the present invention comprises a pulsed electron beam generator for generating a pulsed electron beam, and a hollow tube made of an insulating material. A pulsed electron beam generator connected to the pulsed electron beam generating unit and for guiding the generated electron beam to a target surface, wherein a part of the side surface of the guide tube is a fibrous sheet It is covered with a structure. The sheet-like structure may be made of glass wool or ceramic cloth.

  In the second pulsed electron beam generator, since at least a part of the guide tube is covered with the insulating sheet-like structure, adhesion of the target component to the surface of the guide tube can be partially suppressed. . Further, since the surface of the fibrous sheet-like structure is maintained at a sufficiently low temperature as compared with the surface of the guide tube, re-evaporation of the target component attached to the sheet surface can be suppressed. As a result, it is possible to realize a pulsed electron beam generator that can continuously generate a large number of electron beam pulses.

  Furthermore, after the film forming operation is completed, the target component attached to the surface can be removed simply by peeling the sheet-like structure from the surface of the guide tube and replacing it with a new one. This eliminates the need for periodic cleaning or replacement of the guide tube after completion of the film forming operation, improving the maintainability of the apparatus.

  In order to solve the above-mentioned problems, a third pulsed electron beam generator of the present invention comprises a pulsed electron beam generator for generating a pulsed electron beam, and a hollow tube made of an insulating material. A pulsed electron beam generator connected to the pulsed electron beam generation unit and provided with a guide tube for guiding the generated electron beam to a target surface, and a heating mechanism for heating a side surface of the guide tube is provided. . This heating mechanism may be constituted by a heater embedded in a side wall member constituting the guide tube.

  According to the third pulsed electron beam generator, after the film forming operation is completed, a gas containing oxygen is introduced into the vacuum chamber and the heating mechanism is operated, for example, metal attached to the surface of the guide tube. The target component can be oxidized to form an insulator. If the target component is an insulator, the insulating properties of the guide tube are not impaired. As a result, the guide tube can be regenerated without being cleaned or replaced and used for the next film-forming operation. Therefore, a pulsed electron beam that can stably generate a large number of electron beam pulses continuously. A generator can be obtained. In addition, the maintainability of the film forming apparatus using this pulsed electron beam generator is improved.

  In order to solve the above-described problems, a pulsed electron beam film forming apparatus of the present invention includes a vacuum chamber, a target holding table that is provided in the vacuum chamber and holds a target irradiated with a pulsed electron beam, A substrate holder provided in a vacuum chamber for holding a substrate formed by a target material evaporated by irradiation of a pulsed electron beam to the target, and a pulsed electron beam on the target held by the target holding table A pulsed electron beam film forming apparatus comprising the pulsed electron beam generating apparatus for irradiating the light source, wherein the pulsed electron beam generating apparatus comprises any one of the first to third pulsed electron beam generating apparatuses.

  In the pulsed electron beam deposition apparatus having the above structure, the deterioration of the insulating properties of the guide tube is suppressed, and the re-evaporation of the target component adhering to the guide tube or the like is suppressed, so that the pulsed electron beam generator is continuously stable. Therefore, many electron beam pulses can be generated. As a result, it is possible to execute a film forming operation that can withstand practical use.

  As described above, in the pulsed electron beam generator of the present invention, the deterioration of the insulating properties of the guide tube during film formation is suppressed, and the re-evaporation of the target component adhering to the guide tube and the like is also suppressed. A large number of electron beam pulses can be generated continuously and stably. In addition, in a film forming apparatus using this pulsed electron beam generator, it is possible to carry out a film forming operation that can withstand practical use.

[Embodiment 1]
FIG. 1 is a diagram showing a schematic configuration of a pulsed electron beam film forming apparatus according to Embodiment 1 of the present invention. In the figure, reference numeral 1 denotes a vacuum tank, which has a connecting portion 2 for connecting an exhaust device such as a turbo molecular pump and a connecting portion 3 for connecting a gas introducing device such as a mass flow controller. In the vacuum chamber 1, a target holding unit 5 that holds the target 4 and a substrate holding unit 7 that holds a substrate 6 for film formation are provided. Reference numeral 8 denotes a pulsed electron beam generator for irradiating the target 4 with a pulsed electron beam.

  FIG. 2 is an enlarged view showing the principle of film formation on the substrate 6 by the film formation apparatus of FIG. 1 and the detailed structure of the pulsed electron beam generator 8. In the apparatus of FIG. 1, as shown in FIG. 2, the target material is evaporated and ablated by irradiating the target 4 from the pulsed electron beam generator 8 with a pulsed electron beam at an angle of 40 °, for example. A plasma stream 9 is generated. As the plasma flow reaches the substrate 6 and is deposited, a film of the same material as the target is formed on the substrate 6.

  As shown in FIG. 2, the pulsed electron beam generator 8 includes a pulsed electron beam generator 8a and an insulating guide tube 8b. The guide tube 8 b is provided for guiding the focused pulsed electron beam generated by the pulsed electron beam generator 8 a to the surface of the target 4. In the present embodiment, the guide tube 8b is a cylindrical tube made of an insulating material. There are various theories about the necessity of the guide tube 8b being an insulator, and there is a theory that the guide tube 8b may be metallic as long as it is floating from the pulsed electron beam generating unit 8a. However, the pulsed electron beam generating unit 8a and the vacuum It must be insulated from the tank 1.

  As shown in FIG. 2, the pulsed electron beam generator 8 has a structure in which a cylindrical structure 8c is provided in the vicinity of the tip of the guide tube 8b so as to cover a part of the guide tube 8b. The cylindrical structure 8c is preferably made of an insulating material having a large heat capacity, and a mounting structure to the guide tube 8b is not particularly defined, but a structure in which the heat of the guide tube 8b is not easily transmitted to the cylindrical structure 8c is preferable. .

  FIG. 3A shows a side view of the guide tube 8b with the cylindrical structure 8c attached thereto, and FIG. 3B shows a cross-sectional view thereof. As shown in FIG. 2B, the cylindrical structure 8c is fixed to the guide tube 8b at two points by fixtures 8d and 8e. Therefore, it is difficult for the heat of the guide tube 8b to be transmitted to the cylindrical structure 8c. The fixtures 8d and 8e are preferably made of a material having low thermal conductivity.

  As shown in FIG. 2, when the pulsed electron beam generator 8 irradiates the target 4 with the pulsed electron beam, the target component evaporates and becomes a plasma flow 9 and scatters in the direction of the substrate 6, but part of the guide tube 8b. In this direction, it adheres and accumulates on the surface of the guide tube 8b. Since the cylindrical structure 8c covers a part of the guide tube 8b, adhesion of the target component to the surface of the guide tube 8b is partially prevented. The tip portion of the guide tube 8b becomes a high temperature of about 200 to 300 ° C. during irradiation with the pulsed electron beam, but the cylindrical structure 8c is fixed to the surface of the guide tube 8b by the fixtures 8d and 8e having low thermal conductivity. Since the heat of the guide tube 8b is difficult to be transmitted, the guide tube 8b is kept at a considerably lower temperature than the guide tube 8c during the film forming operation.

  Further, during operation of the pulsed electron beam generator, the inside of the vacuum chamber is depressurized to several mTorr. Therefore, when an element with a high vapor pressure such as Mg or Zn adheres to the guide tube 8b, these substances are re-evaporated. Occur. As described in the section [Means for Solving the Problems], a low-pressure inert gas atmosphere is indispensable for the generation of a pulsed electron beam. When the partial pressure of the evaporated target component increases, Adversely affects outbreaks.

  However, in the guide tube 8b of the present embodiment shown in FIGS. 2 and 3, since the cylindrical structure 8c is maintained at a low temperature even during the operation of the pulsed electron beam generator 8, it is reevaporated from the guide tube 8b. The target component thus condensed is brought into contact with the low-temperature cylindrical structure 8c and adheres thereto. Thereby, the partial pressure of the target component in the vacuum chamber can be kept low enough not to adversely affect the generation of the pulsed electron beam.

  In the present embodiment, the cylindrical structure 8c shown in FIG. 3 does not necessarily have a cylindrical shape, and any shape can be used as long as it can cover the periphery of the side surface of the guide tube 8b. But it ’s okay.

[Embodiment 2]
FIG. 4 is a view showing the structure of the tip portion of the guide tube of the pulsed electron beam generator according to Embodiment 2 of the present invention. The present embodiment is characterized in that a sheet-like structure 8f is wound around the tip of the guide tube 8b. The sheet-like structure 8f is a fibrous or woven structure made of an insulating material that can withstand high temperatures such as glass and ceramics, that is, glass wool or ceramic cloth, and is wound around or peeled off from the guide tube 8b. It is in the form of a sheet so that it can be used. In such a sheet-like structure 8f, when wound around the guide tube 8b, the surface temperature of the sheet is sufficiently lower than the surface of the guide tube 8b, so that the re-evaporation of the target component adhering to the sheet surface is prevented. Can be suppressed.

  Further, when maintenance of the film forming apparatus is performed after the film forming operation is completed, the target component attached to the sheet surface can be easily removed by removing the sheet-like structure 8f from the guide tube 8b and replacing it with a new sheet-like structure. Can be removed. Therefore, there is an effect that it is not necessary to clean the guide tube, which is necessary as part of maintenance of the film forming apparatus.

[Embodiment 3]
FIG. 5 is a cross-sectional view showing the structure of the tip portion of the guide tube of the pulsed electron beam generator according to Embodiment 4 of the present invention. The present embodiment is characterized in that a heating mechanism is provided to the guide tube 8b. That is, as shown in FIG. 5A, the heater 82 is embedded in the member 81 constituting the side wall of the guide tube 8b, or as shown in FIG. 5B, the heater 82 is embedded on the side surface of the guide tube 8b. A heating member 83 is attached.

  During film formation, it is impossible to completely prevent the target component evaporated by irradiation with the pulsed electron beam from adhering to the guide tube 8b. Even when there is little adhesion of the target component and the insulating property of the guide tube 8b is maintained until the end of the film forming operation, the guide tube 8b is washed or guided when the next film forming operation is performed. The tube 8b must be replaced with a new one, and the influence of the target component adhering to the guide tube 8b during the previous film forming operation must be removed.

  However, when the guide tube 8b of the present embodiment is used, when one film forming operation is completed, the gas containing oxygen is filled in the vacuum chamber, and the heater 82 is energized to bring the guide tube 8b to a sufficiently high temperature. Heat. As a result, the conductive material such as metal deposited and deposited on the surface of the guide tube 8b is oxidized to become an insulator, and does not cause a dielectric breakdown of the guide tube. Therefore, the guide tube 8b can be reused without being washed or replaced.

  In FIG. 5, the guide tube 8b provided with a heating mechanism is shown alone, but such a guide tube 8b can also be used as the guide tube shown in the first or second embodiment of the present invention. is there. That is, the guide tube shown in FIG. 3 or 4 can be provided with a heating mechanism as shown in FIG. 5 to improve the maintainability of the guide tube.

[Verification of the effect of the invention]
FIG. 6 is a table comparing results of film formation experiments using a pulsed electron beam film forming apparatus to which the present invention is applied and a conventional pulsed electron beam film forming apparatus. In the experiment, Mg was used as a target material to be placed in the vacuum chamber, and an alumina substrate was placed facing the target material. The pulsed electron beam generator was disposed at an angle of 40 degrees with respect to the target. As the pulsed electron beam generator, PEBS-20 manufactured by Neocera was used, and in the apparatus of the present invention, a guide tube having the structure shown in FIG. 3 was attached. In the conventional apparatus, a guide tube without the cylindrical structure 8c is used. Experimental examples 1, 2, and 3 are performed by changing the diameter of the guide tube, the diameter of the fin, the interval between the fins, and the like.

The experimental conditions are as follows.
Pressure inside vacuum chamber before gas introduction: 3 × 10 ⁻⁸ torr or less Introduced gas type: Ar-1% H ₂
Gas introduction amount: 1.55 cc / min Pressure inside the vacuum chamber after gas introduction: 5 × 10 ⁻³ torr
Acceleration voltage in pulsed electron beam generator: 2 levels shown in FIG. 6 Pulse frequency in pulsed electron beam generator: 5 Hz
Guide tube tip / target surface distance: 3 levels shown in FIG.

  As is apparent by referring to the section of “Total number of pulses until the pulsed electron beam generator detects an abnormality and stops” in FIG. 6, the conventional apparatus generates pulses by generating several hundred pulses. Although the electron beam generator is abnormally stopped, in the apparatus of the present invention, although Mg having a high vapor pressure is used as the target material, the apparatus is within 10,000 pulses in any of Experimental Examples 1, 2, and 3. Never stopped abnormally. Thereby, the remarkable effect of this invention can be understood.

1 is a diagram showing a schematic structure of a pulsed electron beam film forming apparatus according to Embodiment 1 of the present invention. The figure for demonstrating the film-forming principle by the apparatus shown in FIG. The figure which shows the structure of the guide tube shown in FIG. The figure which shows the structure of the guide tube part of the pulsed electron beam generator concerning Embodiment 2 of this invention. The figure which shows the structure of the guide tube part of the pulsed electron beam generator concerning Embodiment 3 of this invention. The table | surface which compared the operation | movement result of the film-forming apparatus concerning this invention, and the conventional film-forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum chamber 4 Target 5 Target holding stand 6 Substrate 7 Substrate holding stand 8 Pulsed electron beam generator 8a Pulsed electron beam generating part 8b Guide tube 8c Cylindrical structure 8d, 8e Joiner 8f Sheet-like structure 81 Guide tube side wall member 82 Heater 83 Heating member

Claims (6)

A pulsed electron beam generator for generating a pulsed electron beam;
In a pulsed electron beam generator comprising: a hollow tube made of an insulating material, and a guide tube connected to the pulsed electron beam generator and guiding the generated electron beam to a target surface;
A pulsed electron beam generator, wherein a cylindrical structure covering at least a part of a side surface of the guide tube is attached with a space from the guide tube surface. A pulsed electron beam generator for generating a pulsed electron beam;
In a pulsed electron beam generator comprising: a hollow tube made of an insulating material, and a guide tube connected to the pulsed electron beam generator and guiding the generated electron beam to a target surface;
A pulsed electron beam generator, wherein a part of a side surface of the guide tube is covered with a fibrous sheet-like structure.   The pulsed electron beam generator according to claim 1, wherein the sheet-like structure is made of glass wool or ceramic cloth. A pulsed electron beam generator for generating a pulsed electron beam;
In a pulsed electron beam generator comprising: a hollow tube made of an insulating material, and a guide tube connected to the pulsed electron beam generator and guiding the generated electron beam to a target surface;
A pulsed electron beam generator having a heating mechanism for heating the side surface of the guide tube.   5. The pulsed electron beam generator according to claim 4, wherein the heating mechanism is a heater embedded in a side wall member constituting the guide tube. A vacuum chamber;
A target holding base for holding a target which is provided in the vacuum chamber and irradiated with a pulsed electron beam;
A substrate holder for holding a substrate formed in a target material provided in the vacuum chamber and evaporated by irradiation of a pulsed electron beam to the target;
In a pulsed electron beam film forming apparatus comprising: a pulsed electron beam generator for irradiating a target held on the target holding table with a pulsed electron beam;
6. A pulsed electron beam film forming apparatus comprising the pulsed electron beam generating apparatus according to any one of claims 1 to 5.

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