JP5544271B2 - Method and apparatus for forming oxide superconductor thin film - Google Patents

Description

  The present invention relates to a film forming method (laser vapor deposition method) and a film forming apparatus (laser vapor deposition apparatus) in which constituent particles hit or evaporated from a target by a laser beam are deposited on a band-shaped substrate to form a thin film.

RE-123-based oxide superconductor (REBa2Cu3O7-x: RE is a rare earth element such as Y, Gd) has a critical temperature higher than the liquid nitrogen temperature (77K), and superconducting devices, superconducting transformers, super Applications to superconducting equipment such as conduction current limiters, superconducting motors or magnets are expected.
In order to use the RE-123 oxide superconductor as a conductor, it is necessary to form a thin film of an oxide superconductor with good crystal orientation on a long substrate such as a tape-like substrate. This is because an electric anisotropy that this kind of rare earth oxide superconductor crystal easily conducts electricity in the a-axis direction and b-axis direction of its crystal axis but hardly conducts electricity in the c-axis direction. This is because, when an oxide superconducting layer is formed on a long substrate, it is necessary to orient the a-axis or b-axis in the direction in which electricity flows and to orient the c-axis in other directions. .
However, in general, since the metal tape itself is polycrystalline and its crystal structure is significantly different from that of the oxide superconductor, it is not possible to form an oxide superconductor thin film with good crystal orientation directly on the metal tape. difficult. Therefore, a technique for forming a polycrystalline intermediate thin film having excellent crystal orientation on a base material made of a metal tape and forming a thin film of an oxide superconductor on the polycrystalline intermediate thin film has been studied.

  As a technique for forming an oxide superconducting layer by forming a RE123-based oxide superconductor on a base material on which a polycrystalline intermediate thin film is formed on a metal tape, the present inventors focused laser light on a target. Research on pulsed laser deposition method (PLD method) that irradiates, evaporates or evaporates constituent particles of the target to generate a plume of constituent particles, and deposits the particles of the plume on a long substrate. (For example, refer to Patent Document 1).

  In FIG. 11, an example of the laser vapor deposition apparatus described in patent document 1 is shown. The laser deposition apparatus 100 includes a first turning member group 103 in which a plurality of turning members are coaxially arranged on one side, and a second turning member group in which a plurality of turning members are coaxially arranged on the other side. 104, a target 107 disposed so as to face the substrate 105 wound so as to form a plurality of lanes between the turning member groups 103 and 104, and a laser light emitting means for irradiating the target 107 with the laser light La 108, a base 106 that supports the base material 105 that travels in the region 111 facing the target 107, a delivery reel 101 that feeds the base material 105 toward the turning member groups 103 and 104, and a winding that winds up the base material 105. A take-up reel 102 is provided.

The delivery reel 101 and the take-up reel 102 are driven in synchronism with each other by a driving device (not shown), and the base member 105 whose direction of movement is turned by the turning member groups 103 and 104 is used as the turning member group 103 and 104. Conveying means for conveying a plurality of rows (a plurality of lanes) between them is configured.
The constituent particles of the target 107 struck or evaporated from the target 107 by the laser beam La become the plume 109, and are deposited on the surface of the base material 105 traveling in the region 111 facing the target 107 to form a thin film. Moreover, since the base material 105 of a plurality of lanes is opposed to the target 107, the area to be deposited at a time can be increased, and the constituent particles in the plume 109 can be used effectively.

JP 2004-263227 A

In the conventional laser vapor deposition apparatus 100 shown in FIG. 11, a heater (not shown) is provided inside a base 106 that supports a base material 105 that travels in a region 111 facing the target 107. The temperature of the film formation surface of the substrate 105 to be formed is controlled by contact heating from the back surface (the surface opposite to the surface on which the thin film is formed).
In order to form a superconducting layer having a high crystal orientation, it is necessary to keep the surface (film formation surface) of the substrate to be formed at an optimum temperature for crystal orientation. However, in the conventional laser deposition apparatus 100, because of the contact heating from the base 106 with a built-in heater, the sensitivity to the temperature fluctuation of the deposition surface due to thermal disturbance such as the movement of the target 109 is low, and the deposition surface Therefore, it is necessary to control the temperature of the base 106 slightly. Further, in the contact heating method from the base 106, the heating is performed from the back surface of the base material 105, and it is difficult to rapidly heat the film forming surface which is the surface of the base material 105. Therefore, the base material 105 is transported at a high speed. When trying to form a film, there is a problem that the heating of the base material 105 becomes insufficient and stable temperature control is difficult.

  In addition, in the heating method from the back surface of the base material 105, if an attempt is made to form a thick film by increasing the number of times of film formation, the contact heating from the back surface of the base material 105 can sufficiently heat the surface of the thick laminated film. Since the base material 105 is separated from the heater before the temperature is transmitted, it is difficult to keep the surface temperature of the base material 105 constant, so that it is difficult to form a superconducting layer having high crystal orientation. In order to solve this problem, it is conceivable to increase the heating temperature by the heater for each lamination, but as the heating temperature increases, the superconducting layer formed with the polycrystalline intermediate thin film formed on the base material 105 Therefore, a solution means that merely raises the heating temperature is not preferred. Furthermore, if the amount of constituent particles scattered from the target 109 is increased to increase the productivity and the film formation rate is increased, the amount of particles deposited on the film formation surface of the substrate 105 increases, and the temperature of the film formation surface is controlled. There was also a problem that became difficult.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the film-forming apparatus and film-forming method which can form the thin film of favorable film quality and a characteristic with favorable productivity.

In order to solve the above problems, the present invention employs the following configuration.
The film forming apparatus of the present invention generates a plume that is a jet of constituent particles that are struck or evaporated from a target by a laser beam, deposits particles from the plume on the surface of the substrate, and deposits on the substrate. A film forming apparatus for forming a thin film, which is disposed between a feeding device and a winding device for moving the base material along a longitudinal direction, and between the feeding device and the winding device. A base material holder that holds the base material in contact with the back surface of the base material that moves between the winding devices, and a target that is disposed to face the surface of the base material in contact with the base material holder And laser light emitting means for irradiating the target with laser light, a heater disposed between the target and the substrate holder so as to face the surface of the substrate, and heating the substrate from the surface side; , At least be prepared When the distance TS between the target and the base material, the distance SH between the base material and the heater, and the shortest distance PH between the center line of the base material holder and the heater are set to SH = 0.55TS-0. .85TS, PH = 0.35TS to 0.55TS is satisfied.
In the film forming apparatus of the present invention, the film forming apparatus includes a turning member that turns a movement direction of the base material disposed between the feeding device and the winding device, and the base material includes the base material holder and the turning member. A plurality of adjacent lanes can be formed by winding a plurality of times between the lanes.
The film forming apparatus of the present invention is preferably used for forming an oxide superconductor thin film.

The film forming method of the present invention irradiates the target surface with a laser beam to knock out or evaporate the constituent particles of the target to generate a plume which is a jet of the constituent particles of the target. A film forming method for forming a thin film on a substrate by passing the substrate through the film forming region and depositing particles from the plume on the surface of the substrate. The base material passing through the substrate is held by a base material holder, and is disposed to face the target at a distance TS between the target and the base material, and the base material and the heater are interposed between the target and the base material holder. The heater is disposed so as to satisfy the distance SH = 0.55TS to 0.85TS, and the shortest distance PH = 0.35TS to 0.55TS between the center line of the base material holder and the heater. By passing the film formation area while heating the substrate from the surface side and forming a thin film on the substrate by.
In the film forming method of the present invention, the thin film may be formed on the base material every time the film forming region passes through the base material a plurality of times.
In the film forming method of the present invention, the target is preferably an oxide superconductor material, and the thin film is preferably an oxide superconductor thin film.

According to the present invention, since the film-forming surface of the base material is heated from the surface side of the base material by the heater disposed at a predetermined position, the temperature of the surface of the base material (film-forming surface) is reduced. It can be stably controlled at an optimum temperature suitable for film formation. Therefore, since the temperature of the film formation surface can be maintained at the optimum temperature, a thin film having good film quality and characteristics can be stably formed.
Further, according to the present invention, since the film formation surface is directly heated from the surface side of the substrate by the heater, the film formation surface of the substrate is sufficiently heated even when the substrate is transported at a high speed. Therefore, the temperature of the film formation surface can be stably controlled. Therefore, a thin film having good film quality and characteristics can be formed with good productivity. In addition, in order to increase productivity, the amount of constituent particles scattered from the target is increased to increase the film formation rate, and heating is performed from the surface side of the substrate. Even if the amount of particles deposited on the surface increases, the temperature of the film formation surface can be stably controlled.
Furthermore, according to the present invention, since heating is performed from the surface (film formation surface) side of the substrate, it is possible to suppress the temperature of the film formation surface from gradually decreasing as the film thickness is increased. There is no need to change the temperature setting. Therefore, when an oxide superconducting film is formed in the present invention, the intermediate layer (polycrystalline intermediate thin film) and the superconducting layer (oxide superconductor thin film) are compared with the heating from the back surface as in the conventional film forming apparatus. The interfacial reaction can be suppressed.

It is a schematic perspective view which shows the oxide superconductor thin film formed into a film on the elongate base material with the film-forming apparatus of this invention. It is a schematic block diagram which shows an example of the film-forming apparatus of this invention. It is a perspective view which shows the principal part of the film-forming apparatus shown in FIG. It is a figure explaining arrangement | positioning of the principal part of the film-forming apparatus shown in FIG. FIG. 5A is a diagram showing a temperature distribution of a substrate passing through a film formation region when an oxide superconducting film is formed using the film forming apparatus and the film forming method of the present invention. ) Is a diagram showing a temperature distribution of a base material passing through a film forming region when an oxide superconducting film is formed using a conventional film forming apparatus and film forming method for heating from the back surface of the base material. It is a schematic block diagram which shows the other example of the film-forming apparatus of this invention. It is a schematic block diagram which shows the other example of the film-forming apparatus of this invention. It is a schematic block diagram which shows the other example of the film-forming apparatus of this invention. 6 is a graph showing the results of Example 1 and Comparative Example 1. It is a graph which shows the result of Example 2 and Comparative Example 2. It is a schematic perspective view which shows an example of the conventional laser vapor deposition apparatus.

  Hereinafter, an embodiment of a film forming method and a film forming apparatus according to the present invention will be described with reference to the drawings. In the embodiment described below, an oxide superconductor thin film will be described as an example of a thin film formed on a long base material, but this oxide superconductor thin film makes the gist of the present invention better understood. Therefore, the present invention will be specifically described, and the present invention is not limited thereto.

FIG. 1 is a schematic perspective view showing an oxide superconductor thin film manufactured using a film forming apparatus according to the present invention. This oxide superconductor thin film 23 is formed on a long tape-shaped metal substrate 21. A long base material in which a polycrystalline intermediate thin film (intermediate layer) 22 such as GZO (Gd ₂ Zr ₂ O ₇ ), YSZ (yttria stabilized zirconia), magnesium oxide (MgO) or the like is formed by an ion beam assisted sputtering method or the like. 25 is formed.

The oxide superconductor thin film 23 is made of an RE123-based oxide superconductor represented by Y ₁ Ba ₂ Cu ₃ O _x , Gd ₁ Ba ₂ Cu ₃ O _x and the like, and has a critical temperature (Tc) of 90 K or more. It is a thin film of oxide superconductor. The oxide superconductor thin film 23 may have a single layer structure or a stacked structure in which a plurality of layers are stacked.

  The thickness of the oxide superconductor thin film 23 is preferably about 1 to 3 μm, and the in-plane uniformity of each layer is extremely excellent. In this oxide superconductor thin film 23, the c-axis, a-axis, and b-axis of each layer of the thin film 23 are epitaxially grown and crystallized so as to match the crystal of the polycrystalline intermediate thin film 22, and the crystal orientation Is excellent.

  As the metal substrate 21, a long metal tape suitably selected from various metal materials such as nickel alloys such as stainless steel, copper, and Hastelloy (trade name, manufactured by Haynes, USA) is preferably used. About 0.1 mm is preferable.

The polycrystalline intermediate thin film (intermediate layer) 22 is made of Gd ₂ Zr ₂ O ₇ (GZO), yttria-stabilized zirconia (YSZ), magnesium oxide (MgO), and the like, and is a collection of crystals having a cubic crystal structure A plurality of fine crystal grains obtained by joining and integrating with each other via a grain boundary is preferably used, and the thickness thereof is, for example, about 1 μm. The c-axis of the crystal axis of each crystal grain is oriented substantially perpendicular to the upper surface (film formation surface) of the metal substrate 21, and the a-axis and the b-axis of each crystal grain are in the same direction. Directed and in-plane oriented. In order to realize such in-plane orientation, an IBAD (Ion Beam Assisted Deposition) method is used as a film forming method.

FIG. 2 is a schematic configuration diagram showing an example of the first embodiment of the film forming apparatus according to the present invention, FIG. 3 is a perspective view showing the main part of the film forming apparatus shown in FIG. 2, and FIG. It is a figure explaining arrangement | positioning of the principal part of the film-forming apparatus shown in FIG.
The film forming apparatus 1 of the present embodiment generates a plume 9 that is a jet of constituent particles struck or evaporated from the target 7 by the laser light L, and the constituent particles from the plume 9 are formed on the long base material 25. This is a film forming apparatus by laser vapor deposition that deposits and forms a thin film of the constituent particles on the long substrate 25.

  The film forming apparatus 1 shown in FIG. 2 and FIG. 3 is a turning member group in which a processing container 2 that houses a long base material 25 and a turning member that turns the moving direction of the long base material 25 are coaxially arranged. 11 and a base member holder 12 formed by coaxially arranging turning members that hold the long base material 25 in contact with the back surface thereof and turn the moving direction of the long base material 25. A feed reel 13 for feeding out the long base material 25 arranged above the group 11, a take-up reel 14 for taking up the long base material 25 arranged above the turning member group 11, and a base material A target 7 disposed so as to face the surface of the base material 25 in contact with the holder 12, a laser light emitting means 6 for irradiating the target 7 placed horizontally with the laser light L, a target 7 and a base The long base material 25 arranged between the material holders 12 is on the surface side. And at least a heater 8 for al heating.

  The turning member group 11 and the base material holder 12 are spaced apart from each other, and the long base material 25 is wound between the turning member group 11 and the base material holder 12 so that the film forming surface side is on the outside. By arranging the turning member group 11 and the substrate holder 12 to circulate, the plurality of lanes are arranged in the film formation region 10 where the plume 9 that is the jet of the constituent particles of the target 7 is generated. ing. The turning member group 11, the base material holder 12, the delivery reel (sending device) 13 and the take-up reel (winding device) 14 are driven from the sending reel 13 by being driven in synchronization with each other by a driving device (not shown). The long base material 25 circulates around the turning member group 11 and the base material holder 12, passes through the film formation region 10 facing the target 7 a plurality of times, and is taken up on the take-up reel 14.

  The turning member group 11 has a configuration in which turning members having the same diameter are coaxially arranged. Each of the diverting members constituting the diverting member group 11 has a curved shape that smoothly turns the moving direction of the long base material 25, such as a columnar shape or a disc shape, a semi-cylindrical shape or a semicircular shape, an elliptical column shape or an elliptical plate shape. Those having a curved side surface (curved surface) are preferred. Each turning member constituting the turning member group 11 may be configured to rotate together with the long base material 25 to be conveyed, or each turning member may not move, and the long base material 25 may slide on the side surface. good. When rotating each turning member constituting the turning member group 11, drive means (not shown) for rotating each turning member in accordance with the moving speed of the long base material 25 may be provided.

The base material holder 12 has a configuration in which turning members having the same diameter are coaxially arranged. The base material holder 12 is moved by each turning member while holding the long base material 25 in contact with the back surface of the base material holder 12. Among the long base materials 25 whose directions are turned, the long base materials 25 that travel in the film forming region 10 that is a portion facing the target 7 are located at an equal distance from the target 7.
Each turning member constituting the base material holder 12 is a columnar shape or a disc shape, a semi-cylindrical shape or a semicircular shape, an elliptical columnar shape or an elliptical plate shape, or the like, for smoothly turning the moving direction of the long base material 25. Those having a curved side surface (curved surface) are preferred. Thereby, the long base material 25 in a state in which the moving direction is turned by the turning member is curved in a convex shape toward the target 7 at a portion facing the target 7. “Cylinder shape or disk shape” is not intended to limit the ratio of the diameter of the turning member to the length in the axial direction.
Each turning member constituting the base material holder 12 may be configured to rotate together with the long base material 25 to be conveyed, or each turning member may not be moved and the long base material 25 may be slid on the side surface. good. When each turning member constituting the substrate holder 11 is rotated, driving means (not shown) for rotating each turning member in accordance with the moving speed of the long substrate 25 may be provided.

  The substrate holder 12 is preferably formed from a material having a relatively large heat capacity. By forming the substrate holder 12 with a large heat capacity, it is possible to suppress temperature fluctuations due to disturbances such as movement of the target 7 and to stabilize the temperature of the film formation surface of the long substrate 25 more stably. Can be held. The material having a relatively large heat capacity constituting the substrate holder 12 is preferably a material having a heat capacity of 400 J / kg · K or more, specifically, Inconel (INCONEL (registered trademark); heat capacity 444 J / kg · K) or the like. A nickel base alloy is mentioned.

A vacuum exhaust device 4 is connected to the processing container 2 through an exhaust hole 3, and the inside of the processing container 2 is depressurized to a predetermined pressure by the vacuum exhaust device 4.
The turning member group 11, the substrate holder 12, the delivery reel 13 and the take-up reel 14 for turning the moving direction of the long substrate 25 are accommodated in the processing container 2, and the inside of the processing container 2 is depressurized to a predetermined pressure. During the time, the entire length of the long base material 25 is placed under reduced pressure in the processing container 2.

A material for the target 7 is appropriately selected according to the composition of the thin film to be formed. When the oxide superconductor thin film 23 having a critical temperature (Tc) of 90 K or higher is formed as a thin film, the composition is the same as or close to that of the desired oxide superconductor thin film 23 or is easily escaped during film formation. A sintered body of a complex oxide containing a large amount of components or a plate body such as an oxide superconductor is used as the target 7.
The oxide superconductor is preferably an RE123-based oxide superconductor represented by Y ₁ Ba ₂ Cu ₃ O _x , Gd ₁ Ba ₂ Cu ₃ O _x , or the like. As the shape of the target 7, for example, a disk shape, a rectangular shape or the like is used.

The laser light emitting means 6 for irradiating the target 7 with the laser light L may be any one that generates the laser light L that can knock out or evaporate the constituent particles from the target 7. The wavelength, output, irradiation energy, and the like of the laser can be appropriately set according to the material of the target 7, the film formation speed, and the like. The laser light emitting means 6 for irradiating the target 27 with the laser light L includes an excimer laser such as Ar-F (193 nm), Kr-F (248 nm), and Xe-Cl (308 nm), a YAG laser, a CO ₂ laser, and the like. Any one may be used.

The processing container 2 is provided with a window 5 for taking in the laser light L of the laser light emitting means 6. In the present embodiment, the laser light emitting means 6 is installed outside the processing container 2, but it can also be arranged inside the processing container 2.
It is preferable that the irradiation position of the laser light L can be moved on the surface of the target 7 by means (not shown) for moving the irradiation position of the laser light L. Thus, by making the irradiation position of the laser beam L movable on the surface of the target 7, it is possible to prevent the target 7 from being locally cut and shortening the life of the target 7. Further, by making the irradiation position of the laser beam L movable on the surface of the target 7, a plurality of plumes 9 from the target 7 are generated, and a film forming region in which the constituent particles of the target 7 are deposited on the substrate 25. 10 can be widened, the uniformity of the concentration of the constituent particles reaching the long base material 25 formed in a plurality of rows on the base material holder 12 is improved, and a thin film having a uniform film thickness, film quality and characteristics is efficiently formed. Can be membrane.

  The target 7 is fixed by a target holder (not shown), and is provided so as to be movable along a parallel plane by a target moving mechanism (not shown). Further, the target 7 is preferably provided so as to be rotatable about the center of the target 7 as an axis. As described above, if the target 7 is provided so as to be movable and rotatable, the surface of the target 7 is scraped almost uniformly even if the film formation is continued for a long time. A problem that the size of the plume 9 is changed can be prevented, and a thin film having a uniform film thickness, film quality, and characteristics can be formed in the longitudinal direction of the long substrate 25.

A heater 8 is disposed between the target 7 and the substrate holder 12 so as to face the surface of the long substrate 25 held by the substrate holder 12. The heater 8 is provided in a portion other than the film formation region 10 where the plume 9 from the target 7 is formed. In the film formation apparatus 1 shown in FIGS. 2 to 4, the two heaters 8 and 8 are formed. Oppositely arranged across the membrane region 10.
The heater 8 can directly heat the long base material 25 from its surface side in a non-contact manner by infrared rays or the like. Examples of the heater 8 include an energizing heater. 2 and 3 show an example in which two heaters 8 are provided. However, the present invention is not limited to this, and may be arranged so as to satisfy the positional relationship described later. A configuration having three or more heaters is also possible. The plurality of heaters 8 and 8 are not limited to the example in which the heaters 8 and 8 are arranged symmetrically with respect to the film formation region 10, and are arranged asymmetrically with respect to the film formation region 10 as long as the positional relationship described later is satisfied. It may be.

FIG. 4 is a schematic diagram for explaining the arrangement of the heaters 8 of the film forming apparatus 1 of the present embodiment. As shown in FIG. 4, the heater 8 includes a distance TS between the target 7 and the long base material 25, a distance SH between the long base material 25 and the heater 8, and a center line A <b> 1 of the base material holder 12 and the heater 8. When the shortest distance PH is set, they are arranged to satisfy SH = 0.55TS to 0.85TS and PH = 0.35TS to 0.55TS. Specifically, the distance TS between the target 7 and the long base material 25 is preferably set in the range of 80 to 150 mm. By setting the distance TS between the target 7 and the long base material 25 within the above range, the constituent particles from the target 7 can be stably oriented on the film formation surface of the long base material 25.
Here, the distance SH between the long base material 25 and the heater 8 represents the shortest distance between the long base material 25 and the heater 8, and the center line A1 of the base material holder 12 (hereinafter referred to as “base material holder center line”). The shortest distance PH between the heater 8 and the heater 8 represents the distance between the base material holder center line A1 and the end 8a of the heater 8, and the film forming apparatus 1 includes a plurality of heaters 8. Is the distance between the end 8a of the heater 8 closest to the film formation region 10 and the substrate holder center line A1.

By arranging the heater 8 so as to satisfy such a relationship, the surface of the long base material 25 is efficiently heated, and the temperature of the surface (film formation surface) of the long base material 25 is easily stabilized. Thus, a thin film having good film quality and characteristics can be formed.
By setting the distance SH between the long base material 25 and the heater 8 to 0.55 TS or more, the distance between the heater 8 and the long base material 25 becomes close, and the surface temperature of the long base material 25 becomes high. It is possible to suppress an interface reaction between the intermediate layer and the oxide superconducting thin film described later. Further, by setting the distance SH between the long base material 25 and the heater 8 to 0.85 TS or less, the long base material 25 and the heater 8 are separated too much, and the transport speed of the long base material 25 is increased. In this case, it can be suppressed that it is difficult to control the surface temperature of the long base material 25 to a desired temperature.

  Further, by setting the shortest distance PH between the base material holder center line A1 and the heater 8 to 0.35 TS or more, the plume 9 which is a jet of constituent particles of the target 7 is not hindered, and the constituent particles are made of the long base material 25. A thin film can be formed by reaching the surface. Further, by setting the shortest distance PH between the substrate holder center line A1 and the heater 8 to 0.55 TS or less, the surface of the long substrate 25 in the film forming region 10 is efficiently heated, and the long substrate 25 The temperature of the surface (film formation surface) can be controlled to a desired temperature.

  FIG. 5 shows a case where heating is performed from the back surface of the base material as in the conventional film forming apparatus shown in FIG. 11 and a case where heating is performed from the front surface side of the long base material 25 by the film forming apparatus 1 of the present embodiment. It is the figure which showed typically the temperature distribution of the base material holder, the elongate base material, and the thin film formed into a film. FIG. 5 shows an example in which a superconducting thin film (oxide superconductor thin film) is formed on a long base material on which an intermediate layer (other crystal intermediate thin film) is formed on a metal base material.

  As shown in FIG.5 (b), in the conventional film-forming apparatus, since it heated from the back surface of the elongate base material by contact heating with the base-material holder with which the heater was incorporated, the base material formed into a film There was a problem that it took some time for the heat to be transferred to the surface, and the temperature of the film formation surface became lower than the optimum temperature suitable for forming a thin film with good film quality. In addition, as the thickness of the thin film (superconducting thin film) is increased so that the long base material passes through the film formation region several times, the heating of the back surface of the long base material increases the temperature of the film formation surface. It became difficult to maintain the optimum temperature, and it was necessary to perform temperature control such as increasing the film formation temperature by several degrees C. for each lamination.

On the other hand, the film forming apparatus 1 of the present embodiment heats the film forming surface of the long base material 25 from the surface side of the long base material 25 by the heater 8 arranged at a predetermined position. As shown to a), the temperature of the surface (film-forming surface) of the elongate base material 25 can be stably controlled to the optimum temperature suitable for forming a thin film with good film quality. Therefore, since the temperature of the surface (film formation surface) of the long base material 25 can be stably maintained at the optimum temperature, a thin film having good film quality and characteristics can be stably formed.
Further, since heating is performed from the surface (film formation surface) side of the long base material 25, it is possible to suppress the temperature of the film formation surface from gradually decreasing as the film thickness of the thin film (superconducting thin film) is increased. So there is no need to change the temperature setting. Therefore, the interface reaction between the intermediate layer and the superconducting thin film caused by raising the film forming temperature can be suppressed as in the conventional film forming apparatus. Therefore, it is possible to form a thick oxide superconducting film without deteriorating characteristics.
Furthermore, in the film forming apparatus 1 of the present embodiment, the film forming surface is directly heated from the surface side of the long base material 25 by the heater 8, so that the long base material 25 is transported at high speed to form a film. Since the film formation surface of the long base 25 can be sufficiently heated, the temperature of the film formation surface can be stably controlled. Therefore, a thin film having good film quality and characteristics can be formed with good productivity. Also, in order to increase productivity, the oscillation frequency of the laser light L from the laser light emitting means 6 is increased, the amount of constituent particles scattered from the target 7 is increased, and the deposition rate is increased. Since the heating is performed from the surface side of the long substrate 25, the temperature of the film forming surface can be stably controlled even if the amount of particles deposited on the film forming surface of the long substrate 25 increases due to an increase in the film forming speed. Can do.

Next, an example of a film forming method using the film forming apparatus 1 will be described as an embodiment of the film forming method of the present invention.
Hereinafter, as an embodiment of a film forming method using the film forming apparatus 1 of the present invention, an oxide superconductor thin film 23 made of Y ₁ Ba ₂ Cu ₃ O _x is formed on a long substrate 25. A film forming method will be described.
A long base material in which a polycrystalline intermediate thin film (intermediate layer) 22 made of Gd ₂ Zr ₂ O ₇ (GZO) is formed on a long tape-like metal base material 21 made of Hastelloy (trade name, manufactured by Haynes, USA) 25 is wound between the substrate holder 12 and the turning member group 11 so that the polycrystalline intermediate thin film 22 side becomes the target 7 side as shown in FIG. Also sets a rectangular target 7 consisting of _Y 1 _Ba 2 _Cu 3 _{O x} as a target of an oxide superconductor.

Next, the inside of the processing container 2 is depressurized to a predetermined pressure by the vacuum exhaust means 4. Here, oxygen gas may be introduced into the processing container 2 as necessary to make the processing container 2 have an oxygen atmosphere.
Next, the delivery reel 13, the turning member group 11, the base material holder 12 and the take-up reel 14 are simultaneously driven, and the long base material 25 is moved from the send reel 13 toward the take-up reel 14 at a predetermined speed. At the same time, the heater 8 is operated to heat the film formation surface from the surface side of the long base material 25 and to control the surface (film formation surface) temperature of the long base material 34 to a desired temperature. The temperature control of the surface (film formation surface) of the long substrate 25 heated by the heater 8 is performed by installing a plurality of temperature sensors at appropriate positions in the processing container 2 and running through the film formation region 10. This can be done by ON / OFF control of the heater 8 so that the temperature of the surface (film formation surface) of the material 25 becomes uniform.

  Next, the target 7 is irradiated with the laser light L by the laser light emitting means 6. At this time, the constituent particles that are struck or evaporated from the target 7 by the laser light L become a plume 9 whose radial cross-sectional area is enlarged, and on the surface of the long base material 25 that runs in the film formation region 10. cover. Further, at this time, it is preferable to move the position of the laser light L irradiated on the surface of the target 7 by amplifying the irradiation position of the laser light L or moving the target 7 in the horizontal direction. As a result, the concentration of the constituent particles that reach the surface of the long base material 25 that is held by the base material holder 12 and forms a plurality of lanes in the film formation region 10 can be made uniform.

  Next, the long base material 25 is allowed to pass through the film formation region 10 while moving in the longitudinal direction while the back surface of the long base material 25 is in contact with the base material holder 12. The long base material 25 passes through the film forming region 10 every time it circulates between the base material holder 12 and the turning member group 11, and a thin film made of an oxide superconductor on the surface of the long base material 25 for each passage. An oxide superconductor thin film 31 is formed.

According to the film forming method of the present embodiment, the heater 8 is arranged at a predetermined position, and the film forming surface is directly heated from the surface side of the long base material 25 by the heater 8. It is possible to form a film while stably controlling the temperature of the surface (deposition surface) to an optimum temperature suitable for forming a thin film with good film quality. Therefore, since the temperature of the surface (film formation surface) of the long base material 25 can be stably maintained at the optimum temperature, a thin film having good film quality and characteristics can be stably formed.
Further, in the film forming method of the present embodiment, since the film forming surface is directly heated from the surface side of the long base material 25 by the heater 8, even when the long base material 25 is transported at high speed to form a film, Since the film formation surface of the long substrate 25 can be sufficiently heated, the film formation can be performed while stably controlling the temperature of the film formation surface. Therefore, a thin film having good film quality and characteristics can be formed with good productivity.

In addition, the film-forming apparatus of this invention is not limited to the structure of the film-forming apparatus 1 of the said embodiment, As long as the arrangement | positioning of a heater satisfy | fills the positional relationship shown in FIG. 4, it can change suitably.
For example, as shown in FIG. 6, a plurality of heaters 8 </ b> B (eight in the example shown in FIG. 6) may be arranged along the curved surface of the opposing base material holder 12, and the base material holder is necessary. The enclosing member 17 may be provided to cover 12 and the heater 8B. When the enclosing member 17 is provided, a window 17 a for taking in the laser light L into the side wall portion of the enclosing member 17, and a plume 9 from the target 7 to the long base material 25 on the bottom surface portion of the enclosing member 17. The opening 16 is provided with windows 17b and 17c for allowing the long base material 25 that moves in the longitudinal direction to pass through the upper surface of the surrounding member 17. At this time, the opening edge portions 17A and 17A that form the opening portion 16 of the surrounding member 17 are set to substantially the same positions as the end portions on the film forming region 10 side of the heater 8B disposed at the closest position of the film forming region 10. It is preferable. By setting it as such an arrangement | positioning, it can suppress that the plume 9 from the target 7 is inhibited by opening edge part 17A, 17A.

The turning member group 11 is omitted, and a plurality of long substrates 25 are conveyed to the substrate holder 12 facing the target 7 by a plurality of sets of delivery reels 13 and take-up reels 14. It is also possible to adopt a configuration in which each long base material 25 arranged in a row passes through the film formation region 10 once.
Moreover, instead of making a base material into multiple rows | lines, as shown in FIG. 7, the width | variety of the elongate base material 25 can also be enlarged. In this case, the substrate holder 12 is not a substrate holder 12 in which a plurality of turning members are arranged coaxially, but a substrate holder 12A made of one turning member having an axial length equal to or greater than the width of the long substrate 34. Can be used.
Further, the roles of the delivery reel 13 and the take-up reel 14 can be interchanged so that the long base material 25 wound up on the reel can be sent again to a position facing the target. It is possible to form a thick film by repeating the reciprocating operation of the long base material 25 between the side reel and the reel on the other end side of the long base material 25.

  Further, in the above-described embodiment, the base material holder 12 disposed to face the target 7 is cylindrical, and the long base material 25 is wound between the base material holder 12 and the turning member group 11. However, the present invention is not limited to this. For example, an apparatus configuration as shown in FIG. In the film forming apparatus 1B shown in FIG. 8, the same or similar components as those in the film forming apparatus 1 shown in FIG.

  A film forming apparatus 1B shown in FIG. 8 includes a pair of turning member groups 11a and 11b that are coaxially arranged with a plurality of turning members that turn the long base material 25 in the moving direction, and are arranged opposite to each other. A feeding reel 13B for feeding out the long base material 25 arranged outside the turning member group 11a, and a take-up reel 14B for taking up the long base material 25 arranged outside the turning member group 11b; The substrate holder 12B is disposed between the turning member groups 11a and 11b and supports the long base members 25 formed in a plurality of rows by winding the turning member groups 11a and 11b, and in contact with the base material holder 12B. A target 7 disposed so as to face the surface of a certain base material 25, laser light emitting means 6 for irradiating the target 7 with laser light L, and a long base disposed between the target 7 and the base material holder 12B Heating the material 25 from the surface side It is configured to include at least a heater 8 that. By turning the turning member groups 11a and 11b, the sending reel 13B and the take-up reel 14B in synchronization with each other by a driving device (not shown), the long base material 25 fed from the sending reel 13B is turned to the turning member group 11a, It passes through the film forming region 10 every time it circulates 11b, and each time it passes, the constituent particles of the target 7 are deposited on the surface of the long base material 25 to form a thin film, which is wound around the take-up reel 14B. It has become. In the film forming apparatus 1B, the delivery reel 13B, the take-up reel 14B, and the turning member groups 11a and 11b are the same as the feed reel 13, the take-up reel 14 and the turning member group 11 of the first embodiment, respectively.

In the film forming apparatus 1B shown in FIG. 8, the base material holder 12B is disposed between the turning member groups 11a and 11b, and the long base material 25 that moves in the longitudinal direction between the turning member groups 11a and 11b. It is held in contact with the back surface. The base material holder 12B has a curved shape in which the surface on the target 7 side bulges gently. The material which comprises the base-material holder 12B is the same as that of the base-material holder 12 of the said 1st Embodiment.
The long base material 25 is wound around the turning member groups 11a and 11b so that the film formation surface is on the outside, and the base material holder 12B is formed in the film formation region 10 where the plume 9 from the target 7 is generated. Are arranged so as to form a plurality of lanes.

  As in the first embodiment, the heater 8 includes the distance TS between the target 7 and the long base 25, the distance SH between the long base 25 and the heater 8, the center line A1 of the base holder 12B and the heater 8 Are set so as to satisfy SH = 0.55TS to 0.85TS and PH = 0.35TS to 0.55TS. Therefore, similarly to the film formation apparatus 1 described above, the film formation surface of the long base material 25 is heated by the heater 8 from the surface side of the long base material 25 and the surface (film formation surface) of the long base material 25 is heated. Since the temperature can be stably maintained at the optimum temperature, a thin film having good film quality and characteristics can be stably formed. In addition, since the film formation surface is directly heated from the surface side of the long base material 25 by the heater 8, the film formation surface of the long base material 25 is also used when the long base material 25 is transported at high speed. Can be sufficiently heated, so that the temperature of the film formation surface can be stably controlled. Therefore, a thin film having good film quality and characteristics can be formed with good productivity.

The film forming method and film forming apparatus of the present invention can be suitably used for forming an oxide superconductor thin film.
In the above-described embodiment, the example in which the film forming method and the film forming apparatus of the present invention are applied when forming an oxide superconductor thin film has been described in detail. For example, a polycrystalline intermediate thin film formed by an IBAD method is used. In the case where the CeO ₂ intermediate layer is formed thereon and then the oxide superconductor thin film is formed, the film forming method and film forming apparatus of the present invention can also be used for forming the CeO ₂ intermediate layer.

  As described above, the film forming method and the film forming apparatus of the present invention have been described, but the present invention is not limited to the above examples, and can be appropriately changed as necessary.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further in detail, this invention is not limited to these Examples.

In the examples shown below, the film forming apparatus of the present invention shown in FIGS. 2 and 3 is used, and in the comparative example, the film forming apparatus shown in FIG. 11 is used to form Y-Ba-Cu- on a long substrate. An O-based (Y ₁ Ba ₂ Cu ₃ O _x ) oxide superconductor thin film was formed. In the examples and comparative examples, the laser scanned a certain area, the number of lanes was 1 lane as shown in FIG. 7, and the oxide superconducting thin film having a thickness of 1 μm was formed by repeating the film formation a plurality of times.
As the long base material, both the examples and the comparative examples are commonly used on a Hastelloy (trade name, manufactured by Haynes, USA) tape having a width of 10 mm and a thickness of 0.1 mm by the IBAD method using Gd ₂ Zr ₂ O ₇ ( A polycrystalline intermediate thin film (intermediate layer) having a thickness of 1 μm made of GZO was used.

Example 1
Adjust the oscillation frequency of the laser beam irradiated to the target by increasing or decreasing the number of laser oscillators (laser light emitting means) at a linear speed (conveying speed of the long base material) of 40 m / h, and the concentration of constituent particles from the target Was adjusted to change the film formation rate per unit area on the surface of the long base material, and the critical current value Ic (A) of the obtained oxide superconductor thin film was measured. Note that the distance TS between the target and the long base material = 100 mm, the distance SH between the long base material and the heater SH = 70 mm, and the shortest distance PH between the center line of the base material holder and the heater = 45 mm. Film formation was performed by controlling the temperature of the film formation surface to about 800 ° C.

(Comparative Example 1)
Film formation was performed in the same manner as in Example 1 except that heating was performed from the back surface of the long base material by contact heating to a base with a built-in heater, and the critical current of the obtained oxide superconductor thin film was obtained. The value Ic (A) was measured.

The results of Example 1 and Comparative Example 1 are shown in FIG.
From the result of FIG. 9, in Comparative Example 1 formed using a conventional film forming apparatus, the critical current value Ic rapidly decreased when the laser oscillation frequency exceeded 300 Hz. On the other hand, in Example 1 formed using the film forming apparatus 1 of the present invention, the critical current value Ic was maintained up to the laser oscillation frequency of 1200 Hz. However, in the film formation with a laser oscillation frequency of 1800 Hz, the laser energy was excessively concentrated on the target, so the target surface was destroyed by strain, a normal plume was not generated, and the film could not be formed in a stable state. The current value Ic is reduced, and it does not reach the limit of the film forming rate at which the film forming apparatus 1 can stably form a film. From this result, it is clear that according to the present invention, an oxide superconductor thin film having good superconducting characteristics can be formed even when a film is formed at a high film formation rate.

(Example 2)
The film was formed with the oscillation frequency of the laser light applied to the target set to 300 Hz and the linear velocity (conveying speed of the long base material) changed, and the critical current value Ic (A) of the obtained oxide superconductor thin film was determined. It was measured. Note that the distance TS between the target and the long base material = 100 mm, the distance SH between the long base material and the heater SH = 70 mm, and the shortest distance PH between the center line of the base material holder and the heater = 45 mm. Film formation was performed by controlling the temperature of the film formation surface to about 800 ° C.

(Comparative Example 2)
Film formation was performed in the same manner as in Example 1 except that heating was performed from the back surface of the long base material by contact heating to a base with a built-in heater, and the critical current of the obtained oxide superconductor thin film was obtained. The value Ic (A) was measured.

The results of Example 2 and Comparative Example 2 are shown in FIG.
From the results of FIG. 10, in Comparative Example 2 formed using a conventional film forming apparatus, the critical current value Ic rapidly decreased when the linear velocity exceeded 40 m / h. On the other hand, in Example 2 formed using the film forming apparatus 1 of the present invention, the critical current value Ic> 300 A up to a linear speed of 160 m / h, and the critical current value Ic is also at a linear speed of 240 m / h. About 280A.
As a result, even when a film is formed at a high linear velocity, an oxide superconductor thin film can be formed without deteriorating the superconducting properties. According to the present invention, a good superconductivity can be achieved with good productivity. It is clear that a characteristic oxide superconductor thin film can be formed.

From the results of FIGS. 9 and 10, in the conventional film forming apparatus, when the number of laser oscillators (laser light emitting means) is increased and the film forming rate is increased, the temperature of the film forming surface can be controlled to a desired temperature. Since it is difficult and the film formation temperature cannot be stabilized, when the laser frequency exceeds 300 Hz, the film quality of the oxide superconductor thin film formed is deteriorated and the superconducting property Ic is deteriorated. In addition, even when the film formation rate of the unit area is lowered, if the linear velocity is increased, it is heating from the back surface of the long base material. Since the long substrate passes through the film formation region, the predetermined film formation temperature cannot be kept stable, and film formation at a linear speed exceeding 40 m / h is difficult.
On the other hand, in the film forming apparatus 1 of the present invention, since the film forming surface is directly heated from the surface side of the long base material, the temperature of the film forming surface is kept at a predetermined temperature even when the film forming rate is increased. An oxide superconducting thin film having good film quality and superconducting characteristics can be produced, which can be maintained stably. In addition, the film forming apparatus 1 of the present invention is not heated from the back side of the substrate as in the conventional film forming apparatus, but directly heats the film forming surface from the substrate surface side. However, the film formation surface could be stably controlled at a desired temperature, and an oxide superconducting thin film having good film quality and superconducting characteristics could be produced with good productivity.

(Example 3)
The linear velocity is 80 m / h, the laser oscillation frequency is 600 Hz, the distance between the target and the long base material is TS = 100 mm, the distance SH between the long base material and the heater, and the shortest distance PH between the center line of the base material holder and the heater. The heater was arranged so as to be in the position shown in Table 1, and the film was formed by controlling the temperature of the film forming surface of the long base material to about 800 ° C. The critical current value Ic (A) of the obtained oxide superconductor thin film was measured. The results are also shown in Table 1.

  From the results of Table 1, in the film forming apparatus 1 of the present invention, the distance SH = 0.55TS to 0.85TS between the long base material and the heater, and the shortest distance PH = 0. It was confirmed that an oxide superconductor thin film having good superconducting characteristics can be formed by forming a film by arranging a heater so as to satisfy the relationship of 35 TS to 0.55 TS.

Example 4
Table 2 shows linear velocity 80 m / h, laser oscillation frequency 600 Hz, distance TS between the target and the long base material, distance SH between the long base material and the heater, and the shortest distance PH between the center line of the base material holder and the heater. The heater was arranged so as to be in the position shown in FIG. 5 and the film was formed by controlling the temperature of the film forming surface of the long base material to about 800 ° C. The critical current value Ic (A) of the obtained oxide superconductor thin film was measured. The results are shown in Table 2.

  From the results of Table 2, in the film forming apparatus 1 of the present invention, the distance SH = 0.55TS to 0.85TS between the long base material and the heater, and the shortest distance PH = 0. It was confirmed that an oxide superconductor thin film having good superconducting characteristics can be formed by forming a film by arranging a heater so as to satisfy the relationship of 35 TS to 0.55 TS. In particular, it was confirmed that an oxide superconducting thin film having better superconducting characteristics can be formed by forming a film with the distance TS between the target and the long base material in the range of 80 to 150 mm.

  The present invention relates to a film forming method and a film forming apparatus for forming a thin film by irradiating a target with laser light, knocking out or evaporating constituent particles of the target, and depositing the constituent particles on a belt-like substrate. Widely applicable to.

  DESCRIPTION OF SYMBOLS 1, 1B ... Film-forming apparatus, 2 ... Processing container, 4 ... Vacuum exhaust apparatus, 6 ... Laser light emission means, 7 ... Target, 8, 8B ... Heater, 9 ... Plume, 10 ... Film-forming area | region, 11, 11a, 11b ... Turning member group, 12, 12A, 12B ... Base material holder, 13, 13B ... Delivery roll, 14, 14B ... Winding roll, 21 ... Metal base material, 22 ... Polycrystalline intermediate thin film (intermediate layer), 23 ... Thin film (oxide superconductor thin film), 25 ... long base material (base material), L ... laser light.

Claims (4)

A plume that is a jet of constituent particles struck or evaporated from a target by a laser beam is generated, and particles from this plume are deposited on the surface of the substrate to form an oxide superconductor thin film on the substrate. A film forming apparatus,
A feeding device and a winding device for moving the substrate along the longitudinal direction;
A base material holder disposed between the feeding device and the winding device, and holding the base material in contact with the back surface of the base material moving between the feeding device and the winding device;
A target disposed opposite to the surface of the substrate in contact with the substrate holder;
Laser light emitting means for irradiating the target with laser light;
A heater disposed between the target and the substrate holder so as to face the surface of the substrate, and heating the substrate from the surface side;
Comprising at least
When the distance TS between the target and the substrate, the distance SH between the substrate and the heater, and the shortest distance PH between the center line of the substrate holder and the heater, SH = 0.55TS to 0.85TS. , PH = 0.35TS to 0.55TS is satisfied, A film forming apparatus for an oxide superconductor thin film. A turning member for turning the moving direction of the base material disposed between the feeding device and the winding device;
2. The oxide superconductor thin film according to claim 1, wherein the base material is wound a plurality of times between the base material holder and the turning member to form a plurality of adjacent lanes. apparatus. The surface of the target made of an oxide superconductor material is irradiated with laser light, and the constituent particles of the target are knocked out or evaporated to generate a plume that is a jet of the target constituent particles. A film forming method for forming an oxide superconductor thin film on the substrate by passing the substrate through the film forming region and depositing particles from the plume on the surface of the substrate,
Holding the base material passing through the film-forming region by a base material holder, and disposing the target at a distance TS between the target and the base material,
Between the target and the substrate holder, a distance SH = 0.55TS to 0.85TS between the substrate and the heater, and a shortest distance PH = 0.35TS between the center line of the substrate holder and the heater Arrange the heater to meet 0.55TS,
Method of forming the oxide superconductor thin film and forming said oxide superconductor thin film on the film formation region is passed through a by on the substrate while heating the substrate from the surface side by the heater. 4. The oxide according to claim 3 , wherein the oxide superconductor thin film is formed on the base material every time the film formation region passes through the base material a plurality of times . A method for forming a superconductor thin film.

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