JP6304389B2 - Electron beam deposition apparatus and thin film manufacturing method - Google Patents

Description

  The present invention relates to an electron beam evaporation apparatus and a thin film manufacturing method using the same.

  In the electron beam vapor deposition apparatus, the entire electron beam incident on the crucible is not used for heating the vapor deposition material, but a part of the electron beam is reflected on the surface of the vapor deposition material. When the reflected electrons are incident on the film formation substrate, the substrate surface may be damaged.

  In order to prevent damage to the substrate surface due to such a reason, a method of applying a magnetic field in a direction parallel to the surface of the film formation substrate is often used (for example, Japanese Patent Laid-Open No. 7-211641 (Patent Document 1) )reference). Since the reflected electrons are deflected by the magnetic field in the direction parallel to the substrate, it is possible to prevent the reflected electrons from entering the deposition substrate.

JP-A-7-211641

  By the way, in order to increase the film forming speed, it is necessary to bring the thin film forming substrate close to the crucible. However, when the film formation substrate and the crucible are brought close to each other in the apparatus configuration of the above document, the magnetic field for shielding the reflected electrons will affect the electron beam incident on the crucible, and the electron beam is made to the crucible with high accuracy. The problem is that it is difficult to guide.

  The present invention has been made in consideration of the above-mentioned problems, and its main purpose is to accurately guide the electron beam into the crucible even when the crucible and the film formation target are relatively close to each other. It is possible to provide an electron beam evaporation apparatus capable of preventing reflection electrons from entering a film formation target.

  An electron beam vapor deposition apparatus according to the present invention generates a crucible for filling a vapor deposition material, a holding unit for holding a film formation target for depositing an evaporated vapor deposition material, and an electron beam incident on the vapor deposition material. The electron gun, a first magnetic field generator, and a magnetic shield. The first magnetic field generator generates a first magnetic field for deflecting reflected electrons reflected by the vapor deposition material. The magnetic shield shields the first magnetic field so that the first magnetic field does not affect the trajectory of the electron beam.

  According to the above configuration, the reflected electrons can be deflected by the first magnetic field generated by the first magnetic field generator, so that the reflected electrons can be prevented from entering the film formation target. Furthermore, since the first magnetic field is shielded by the magnetic shield, the electron beam can be accurately guided into the crucible.

  Preferably, the magnetic shield is provided above the crucible and below the first magnetic field generator. Preferably, when viewed from directly above the crucible, the first magnetic field generator is provided on the opposite side to the incident direction of the electron beam. Preferably, the magnetic shield is provided on the side opposite to the incident direction of the electron beam when viewed from directly above the crucible.

  With the arrangement of the magnetic shield and the first magnetic field generator, the reflected electrons can be efficiently deflected and the first magnetic field generated by the first magnetic field generator can be efficiently shielded.

  Preferably, the first magnetic field generating unit includes first and second permanent magnets facing each other in the horizontal direction, and a yoke. The yoke connects the opposite side of the first permanent magnet opposite to the second permanent magnet and the opposite side of the second permanent magnet opposite to the first permanent magnet. Preferably, the first and second permanent magnets are provided below the film formation target. More preferably, when the first magnetic field generator is not provided, the reflected electron trajectory flying at the maximum elevation angle in the range in which reflected electrons having a predetermined threshold density or more are observed, and the first and first Said 1st and 2nd permanent magnet is arrange | positioned so that the straight line which ties between two permanent magnets may cross | intersect.

  With the configuration of the first magnetic field generator, the first magnetic field for deflecting the reflected electrons can be efficiently generated.

  Preferably, the magnetic shield is plate-shaped. When viewed from directly above the crucible, the end of the plate-like magnetic shield close to the crucible has a shape recessed in an arc. More preferably, the electron beam evaporation apparatus further includes a rotating unit for rotating the holding unit during film formation. In this case, the magnetic shield is provided close to a virtual cone connecting the surface of the holding portion facing the crucible and the center of the opening of the crucible.

  By the shape and arrangement of the magnetic shield, it is possible to shield as much as possible the vapor deposition material released from the crucible toward the film formation target.

  Preferably, the electron beam evaporation apparatus further includes a second magnetic field generation unit that generates a second magnetic field for controlling the trajectory of the electron beam. The magnetic shield is separated from the first magnetic field generator downward by a first distance or more according to the strength of the first magnetic field and from the crucible upwards according to the strength of the second magnetic field. It is arranged in a height range separated by a distance of 2 or more. More preferably, a magnetic shielding body is arrange | positioned at the lowest end of said height range.

  The arrangement of the magnetic shield described above can prevent the first magnetic field generated by the first magnetic field generator and the second magnetic field generated by the second magnetic field generator from being weakened as much as possible. The ratio of the leakage magnetic field of the first magnetic field from the magnetic shield to the second magnetic field is preferably 0.05 or less.

  In another aspect, the present invention is a thin film manufacturing method for forming a thin film using the electron beam evaporation apparatus.

  According to this invention, even when the crucible and the film formation target are relatively close to each other, it is possible to accurately guide the electron beam into the crucible and prevent reflection electrons from entering the film formation target. It is possible to provide an electron beam evaporation apparatus capable of performing the above.

It is a figure which shows typically the structure of the electron beam vapor deposition apparatus by one Embodiment. It is a perspective view inside the vacuum vessel of FIG. It is a top view inside the vacuum container of FIG. It is a figure for demonstrating the function of the yoke provided in the 1st magnetic field generation part for reflection electron deflection. It is a figure for demonstrating in more detail about arrangement | positioning of a magnetic shielding body. It is a figure for demonstrating arrangement | positioning of the 1st magnetic field generation part for reflection electron deflection. It is a flowchart which shows the procedure of the thin film preparation method.

  Hereinafter, an embodiment will be described in detail with reference to the drawings. The same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

[Configuration of electron beam evaporation system]
FIG. 1 is a diagram schematically illustrating a configuration of an electron beam vapor deposition apparatus 100 according to an embodiment. FIG. 2 is a perspective view of the inside of the vacuum vessel of FIG. FIG. 3 is a top view of the inside of the vacuum vessel of FIG. In FIG. 1, the cross section is hatched. In FIG. 3, the holder 6 is indicated by a broken line, and an arrangement below the holder 6 is shown.

  1-3, let the left-right direction of the electron beam vapor deposition apparatus 100 be an X-axis direction, let the front-back direction be a Y-axis direction, and let the up-down direction be a Z-axis direction. The X-axis direction and the Y-axis direction are horizontal directions, and the Z-axis direction is a vertical direction. When distinguishing the right and left in the X-axis direction, the distinction is made by adding a symbol such as + X direction and -X direction. The same applies to the Y-axis direction and the Z-axis direction.

  1 to 3, the electron beam evaporation apparatus 100 includes a vacuum vessel 2, a holder (holding unit) 6 provided therein, a crucible 14, an electron gun 16, a first magnetic field generation unit 30, In addition, the magnetic shield 40, the vacuum pump 24, the motor 10, and the control unit 26 are included.

  The vacuum vessel 2 is provided with a front door 4 for a user's work. Further, in order to observe the inside of the vacuum vessel 2 during film formation, the front door 4 is provided with a window portion (not shown). The inside of the vacuum vessel 2 can be evacuated by a vacuum pump 24 through an exhaust pipe 22.

  The holder 6 has a dome shape, and a substrate or the like is attached as an object to be formed on the facing surface (the lower surface of the holder 6) facing the opening of the crucible 14. The holder 6 is connected to a motor 10 via a rotating shaft 8 coupled to the upper part thereof. The holder 6 is rotated during film formation by driving the rotating shaft 8 by the motor 10.

  The crucible 14 is attached to the central part of the table 12 provided at the lower part of the vacuum vessel 2. The inside of the crucible 14 is filled with a vapor deposition material. In electron beam evaporation, the evaporation material is evaporated by being heated by the electron beam, and the evaporated evaporation material is deposited on the surface of the film formation target to form a thin film.

  The electron gun 16 is provided below the table 12. In the case of FIG. 1, the electron beam 20 emitted from the electron gun 16 has an arc shape with a central angle of 270 ° by a second magnetic field B2 in the + Y direction generated by a second magnetic field generator (not shown) of the electron gun 16. The trajectory is drawn and the crucible 14 is reached. An opening 18 through which the electron beam 20 passes is formed in the table 12.

  Not all of the electron beam 20 incident on the crucible 14 is used for heating the vapor deposition material. A part of the electron beam 20 is reflected by the vapor deposition material filled in the crucible 14. When the reflected electrons 34 are incident on a substrate as a film formation target, the surface of the substrate may be damaged. Therefore, in order to deflect the reflected electrons 34, a first magnetic field generator 30 that generates a first magnetic field B1 in the + Y direction is provided in the region 32 below the holder 6. Since the reflected electrons are generally distributed around the specular reflection direction with respect to the incident direction of the electron beam 20, the first magnetic field generator 30 is opposite to the incident direction of the electron beam 20 when the crucible 14 is viewed from directly above. It is desirable to be provided on the side.

  A more detailed configuration example of the first magnetic field generation unit 30 will be described with reference to FIGS. 2 and 3. The first magnetic field generation unit 30 includes permanent magnets 44 </ b> A and 44 </ b> B that face each other in the Y-axis direction, and a yoke 46. Including. The yoke 46 connects the opposite side of the permanent magnet 44A opposite to the permanent magnet 44B and the opposite side of the permanent magnet 44B opposite to the permanent magnet 44A. The opposing surfaces of the permanent magnets 44A and 44B are the north and south poles of the magnetic pole, respectively. The permanent magnets 44 </ b> A and 44 </ b> B are provided below the holder 6. The yoke 46 has a structure in which plate rod-like members 46A, 46B, and 46C formed of a magnetic material such as iron are connected in a U shape.

  FIG. 4 is a diagram for explaining the function of the yoke provided in the first magnetic field generation unit 30 for backscattered electron deflection. As shown in FIG. 4, by providing the yoke 46, the magnetic field lines 48 can pass through the inside of the yoke, and the density of the magnetic flux 50 generated in the space between the permanent magnets 44A and 44B can be increased.

  Next, the magnetic shield 40 will be described with reference to FIGS. 1 to 3 again. In general, in order to increase the deposition rate, it is necessary to make the distance between the holder 6 and the crucible 14 closer. However, when the first magnetic field generation unit 30 for reflection electron deflection is provided, the first magnetic field B1 generated by the first magnetic field generation unit 30 affects the trajectory of the electron beam 20, and the electron It becomes difficult to guide the beam 20 to the crucible 14 with high accuracy. Therefore, in the present embodiment, a magnetic shield 40 made of a magnetic material such as iron is provided inside the vacuum vessel 2 in order to shield the first magnetic field B1 from the first magnetic field generator 30.

  Hereinafter, a detailed configuration and arrangement of the magnetic shield 40 will be described. In the case of the example shown in FIGS. 1 to 3, the magnetic shield 40 is formed in a plate shape and is fixed on the table 12 by shafts 42 </ b> A, 42 </ b> B, 42 </ b> C. The magnetic shield 40 is provided above the crucible 14 and below the first magnetic field generator 30. In order not to shield the vapor deposition material released from the crucible 14 toward the holder 6, when viewed from directly above the crucible 14, the end of the magnetic shield 40 on the side close to the crucible 14 has an arcuate shape. Have. The thickness of the plate-like magnetic shield 40 is set to a thickness sufficient to shield the first magnetic field B1.

  Further, in order to efficiently shield the first magnetic field B1 by the first magnetic field generation unit 30 (that is, with the magnetic shield 40 having a small area as much as possible), when the crucible 14 is viewed from directly above, the magnetic The shield 40 is preferably provided on the same side as the first magnetic field generator 30 with respect to the crucible 14 (that is, on the side opposite to the incident direction of the electron beam 20). In this case, since a space is provided on the front door 4 side of the vacuum vessel 2, there is an advantage that an operation such as filling the crucible 14 with an evaporation material becomes easy. If importance is attached to shielding the first magnetic field B1 by the first magnetic field generator 30 as much as possible and workability is not important, for example, a donut-shaped magnetic shield may be used.

  The control unit 26 is configured based on a computer and controls operations of the vacuum pump 24, the electron gun 16, the motor 10 for rotating the holder 6, and the like.

[Arrangement of magnetic shield]
FIG. 5 is a diagram for explaining the arrangement of the magnetic shields in more detail. In FIG. 5, the cross-sectional portion is hatched. Substrate 52A, 52B, 52C, 52D as a film formation target is attached to the lower surface of the holder 6 (surface 6A facing the crucible 14).

  First, the horizontal arrangement of the magnetic shield 40 will be described with reference to FIG. As described above, the magnetic shield 40 is provided on the side opposite to the incident direction of the electron beam 20 when the crucible 14 is viewed from directly above. Further, in order not to shield the vapor deposition material released from the crucible 14 toward the holder 6, the magnetic shield 40 is formed on the cone 60 connecting the center of the opening of the crucible 14 and the facing surface 6 </ b> A of the holder 6. It is provided as close as possible.

  Next, the arrangement of the magnetic shield 40 in the vertical direction (vertical direction) will be described. As already described, the magnetic shield 40 is provided above the crucible 14 and below the first magnetic field generator 30. However, in this case, it is not desirable to place the magnetic shield 40 formed of a magnetic material too close to the first magnetic field generating unit 30 or conversely too close to the crucible 14. If the magnetic shield 40 is brought too close to the first magnetic field generator 30, the magnetic shield 40 works to absorb the first magnetic field B1 generated by the first magnetic field generator 30, so that the reflected electrons are sufficient. This is because it becomes impossible to deflect. Similarly, if the magnetic shield 40 is too close to the crucible 14, the magnetic shield 40 works to absorb the second magnetic field B 2 generated by the electron gun 16, so that the trajectory control of the electron beam 20 cannot be sufficiently performed. Because.

  Therefore, as shown in FIG. 5, the magnetic shield 40 is disposed in a height range MR that is separated from the first magnetic field generating unit 30 by a distance DU or more downward and separated from the crucible 14 by a distance DL or more. . Here, the distance DU is determined according to the strength of the first magnetic field B1 (the distance DU is shortened as the strength of the first magnetic field B1 is increased), and the distance DL is determined according to the strength of the second magnetic field B2. (The greater the intensity of the second magnetic field B2, the shorter the distance DL). Furthermore, it is desirable to arrange the magnetic shield 40 at the lowermost end of the height range MR. As a result, the cross-sectional area of the aforementioned cone 60 is reduced, so that the magnetic shield 40 can be disposed closer to the crucible 14.

  In the magnetic shield 40, the ratio of the leakage magnetic field of the first magnetic field B1 from the magnetic shielding body 40 to the second magnetic field B2 is 0.05 or less (that is, the magnitude of the leakage magnetic field of the first magnetic field B1 is It is desirable that the second magnetic field B2 be 0.05 times or less the magnitude of the second magnetic field B2. Here, the leakage magnetic field of the first magnetic field B1 means that the first magnetic field B1 generated by the first magnetic field generation unit 30 leaks from the magnetic shield 40 without being completely shielded by the magnetic shield 40. A magnetic field. For example, when the magnetic shield 40 is plate-shaped, the thickness of the magnetic shield 40 is increased so that the ratio of the leakage magnetic field of the first magnetic field B1 to the second magnetic field B2 is 0.05 or less. Under these conditions, the result was obtained that the positional deviation of the electron beam was so small that it could not be visually confirmed. On the other hand, when the magnetic shield 40 is formed so that the ratio of the leakage magnetic field of the first magnetic field B1 to the second magnetic field B2 is greater than 0.05, the positional deviation of the electron beam is visually confirmed. The result was as large as possible.

[Arrangement of magnetic field generator for reflection electron deflection]
FIG. 6 is a diagram for explaining the arrangement of the first magnetic field generation unit 30 for backscattered electron deflection. In FIG. 6, the cross section of the first magnetic field generation unit 30 is hatched.

  In general, the reflected electrons reflected by the vapor deposition material in the crucible 14 are distributed with the specular reflection direction of the incident electron beam approximately in the center. The graph of FIG. 6 schematically shows the distribution of reflected electron density (current density) when the first magnetic field generating unit 30 is not provided. The graph of FIG. 6 shows that reflected electrons exceeding a predetermined threshold density are observed at an elevation angle in the range of 0 to θ (when reflected electrons exceeding the threshold density are incident on the substrate, the substrate is damaged. there is a possibility). In this case, since the angle at which the reflected electrons should be deflected becomes the largest at the maximum elevation angle θ, the permanent magnets 44A and 44B have a line segment connecting the trajectory of the reflected electrons flying at the maximum elevation angle θ and the permanent magnets 44A and 44B. It is desirable to arrange them so that they intersect. Thereby, the strongest first magnetic field B1 can be applied to the reflected electrons flying at the maximum elevation angle θ.

[Thin film production method]
FIG. 7 is a flowchart showing the procedure of the thin film manufacturing method. Hereinafter, the above description will be summarized and a procedure of a thin film manufacturing method using the electron beam evaporation apparatus 100 described with reference to FIGS. 1 to 6 will be described.

  First, the electron beam vapor deposition apparatus 100 provided with the 1st magnetic field generation part 30 and the magnetic shielding body 40 is prepared (step S110). Since the first magnetic field generator 30 and the magnetic shield 40 have no control mechanism, the first magnetic field generator 30 always generates the first magnetic field B1. The first magnetic field generator 30 for deflecting the reflected electrons is attached below the holder 6 and on the opposite side of the incident direction of the electron beam 20 when viewed from directly above the crucible 14. The magnetic shield 40 is attached below the first magnetic field generator 30 and above the crucible 14. When viewed from directly above the crucible 14, the magnetic shield 40 is provided on the side opposite to the incident direction of the electron beam 20, and the center of the opening of the crucible 14 and the lower surface of the holder 6 (facing surface 6 </ b> A facing the crucible 14). Are arranged as close as possible to the cone 60 connecting the two.

  Thereafter, the crucible 14 is filled with a vapor deposition material (step S120), and a film formation target is attached to the lower surface of the holder 6 (step S130). After evacuating the inside of the vacuum vessel 2 (step S140), the vapor deposition material is heated and evaporated by an electron beam, thereby forming a thin film on the surface of the film formation target (step S150). After the formation of the thin film with a predetermined thickness is completed, the inside of the vacuum vessel 2 is returned to atmospheric pressure, and the film formation target after the thin film formation is taken out from the vacuum vessel 2 (step S160).

[Summary]
As described above, according to the electron beam evaporation apparatus 100 of the present embodiment, it is possible to prevent the reflected electrons from entering the film formation target by providing the first magnetic field generation unit 30. Furthermore, by providing the magnetic shield 40 above the crucible 14 and below the first magnetic field generator 30, the first magnetic field B1 generated by the first magnetic field generator 30 affects the trajectory of the electron beam. I can not. As a result, even when the crucible 14 and the film formation target are relatively close to each other, it is possible to accurately guide the electron beam into the crucible 14 and to prevent the reflected electrons from entering the film formation target. It is possible.

  It should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  For example, in the above embodiment, the electron gun 16 includes the second magnetic field generator (not shown) that generates the second magnetic field B2 for controlling the trajectory of the electron beam. Is not limited. In addition to the electron gun 16 that generates the electron beam, a second magnetic field generation unit that generates a second magnetic field may be provided to control the trajectory of the electron beam. For example, the second magnetic field generator that generates the second magnetic field B2 may include a pair of permanent magnets provided outside the electron gun and a yoke. The yoke connects the opposite side of the opposing surface of one permanent magnet to the opposite side of the opposing surface of the other permanent magnet.

  2 vacuum container, 4 front door, 6 holder (holding part), 6A facing surface, 14 crucible, 16 electron gun, 20 electron beam, 30 first magnetic field generating part, 34 backscattered electrons, 40 magnetic shield, 44A, 44B Permanent magnet, 46 yoke, 52A, 52B, 52C, 52D substrate, 60 cone, 100 electron beam evaporation apparatus, B1 first magnetic field, B2 second magnetic field.

Claims (9)

A crucible for filling the vapor deposition material;
A holding unit for holding a film formation target for depositing the evaporated vapor deposition material;
An electron gun for generating an electron beam incident on the vapor deposition material;
A first magnetic field generator for generating a first magnetic field for deflecting reflected electrons reflected by the vapor deposition material;
An electron beam evaporation apparatus comprising: a magnetic shield that shields the first magnetic field so that the first magnetic field does not affect the trajectory of the electron beam.   The electron beam evaporation apparatus according to claim 1, wherein the magnetic shield is provided above the crucible and below the first magnetic field generator.   3. The electron beam evaporation apparatus according to claim 1, wherein the first magnetic field generation unit is provided on a side opposite to an incident direction of the electron beam when viewed from directly above the crucible.   The electron beam evaporation apparatus according to any one of claims 1 to 3, wherein the magnetic shield is provided on a side opposite to an incident direction of the electron beam when viewed from directly above the crucible. The first magnetic field generator is
First and second permanent magnets facing in the horizontal direction;
Including a yoke,
The yoke connects the opposite side of the first permanent magnet facing the second permanent magnet and the opposite side of the second permanent magnet facing the first permanent magnet. Item 5. The electron beam evaporation apparatus according to any one of Items 1 to 4.   The electron beam vapor deposition apparatus according to claim 5, wherein the first and second permanent magnets are provided below the film formation target.   When the first magnetic field generator is not provided, the reflected electron trajectory flying at the maximum elevation angle in the range in which reflected electrons of a predetermined threshold density or more are observed, and the first and second The electron beam deposition apparatus according to claim 6, wherein the first and second permanent magnets are arranged so that a straight line connecting the permanent magnets intersects. The magnetic shield is plate-shaped,
The electron according to any one of claims 1 to 7, wherein when viewed from directly above the crucible, an end portion of the plate-shaped magnetic shield close to the crucible has an arcuate shape. Beam evaporation equipment. The thin film preparation method which forms a thin film using the electron beam vapor deposition apparatus of any one of Claims 1-8 .

Images