JPH10130839A - Thin film forming device and method for driving shutter to be used for this device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure the formation of uniform thin films on a substrate surface and decrease the deposition of film forming materials depositing on the inside wall of the chamber of a device, the rotating mechanism of a substrate supporting body, etc., by forming a shutter as a rotary type shutter consisting of a columnar body having an aperture penetrating in a direction orthogonal with the revolving shaft of this columnar body. SOLUTION: The shutter disposed between the molecular beam source 10 and substrate supporting body 16 of, for example, a molecular beam epitaxy device is formed as the rotary type shutter 12 consisting of the columnar body 12a having the aperture 12b. The aperture 12b is disposed to penetrate the columnar body 12a in the direction orthogonal with the revolving shaft 14 of the columnar body 12a. The shutter revolving shaft 14 is connected to the rotary type shutter 12 and is connected to a rotational driving means, by which the rotation of the rotary type shutter 12 is made possible. At the time of opening and closing the rotary type shutter 12, the substrate supporting body 16 is rotated and when this body comes to a prescribed position, this position is detected and is synchronized with the rotating angle of the substrate supporting body 16 to rotate the rotary type shutter 12 from the close state to the open state or opposite thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a thin film forming apparatus and a method of driving a shutter used in the apparatus.

[0002]

2. Description of the Related Art Conventionally, a molecular beam epitaxy (MBE) apparatus has been used as a thin film forming apparatus. As a driving method for opening and closing a shutter used in the molecular beam epitaxy (MBE) apparatus, there are three typical opening and closing methods.

A first opening / closing method uses a disk-shaped shutter installed between a molecular beam source and a rotary substrate support, and uses an opening / closing axis provided perpendicular to the shutter surface of the shutter as a center. This is a method of opening and closing a shutter by rotating horizontally at a predetermined rotation angle. The second opening / closing method is a method of using a disk-shaped shutter to open / close the shutter by reciprocating an opening / closing axis provided in the shutter surface of the shutter in a linear direction. A third opening / closing method is a method in which a disk-shaped shutter is used to move the shutter to open and close in the vertical direction.

When a thin film is formed on a substrate surface by the third opening / closing method described above, first, the substrate support on which the substrate is mounted is rotated, and then the shutter is moved to a predetermined position on the substrate support. When it comes, the shutter is opened and closed in the vertical direction, and then a molecular beam is generated to form a film on the surface of the substrate mounted on the substrate support.

Looking at the variation distribution of the molecular beam due to the shutter opening / closing operation in the above-described first, second and third shutter opening / closing methods, the first to third opening / closing methods show that the shutter is closed (closed). ) During the period from the position to the open (open) position, the molecular beam is first generated from the periphery of the molecular beam source, and then the substrate is moved when the shutter moves to the center of the molecular beam source. Molecular beams are distributed in about half the area of the surface.

Further, when the shutter is opened, the molecular beam is uniformly distributed over the entire area of the substrate surface. On the other hand, when the shutter is closed, the molecular beam has a fluctuation distribution just opposite to the movement from the closed position to the open position.

[0007]

However, the conventional method of opening and closing the shutter of the MBE apparatus has the following problems.

When the film formation layer formed on the substrate surface is changed from a few atomic layers to a monoatomic layer, the reciprocating movement time due to the opening and closing movement of the shutter is shortened. For this reason, a film formation period during which the shutter moves from the open state to the closed state is also shortened. When the film formation period is shortened in this manner, in the conventional shutter opening / closing method, film formation does not start on the substrate surface unless the shutter moves to the center of the molecular beam source. Increase to deteriorate the film properties.

When the shutter is opened, the molecular beam is diffused, so that the film-forming substance adheres and accumulates on the peripheral portion other than the substrate, for example, on the rotation mechanism of the substrate support or on the upper wall surface of the chamber. As described above, when the film-forming substance adheres to the periphery of the substrate, an unnecessary gas adheres to the film-forming substance and raises the pressure in the chamber, or the film-deposited substance peels and becomes an impurity (contamination) therein. And deteriorates the film formation environment, the time and labor required for cleaning the inside of the chamber, and the cleaning maintenance period of the shutter is short.

When the substrate support is rotated during film formation, a predetermined position of the substrate support and the opening start position of the shutter are conventionally synchronized. However, the shielding position of the shutter is determined by the operating time of the shutter drive unit. And does not always coincide with the initial position of the substrate support. As described above, if the shutter blocking position does not coincide with the predetermined position of the substrate support, the molecular beam intensity distributions when the shutter is opened and when the shutter is closed are different, so that the molecular beam intensity distribution on the substrate surface becomes non-uniform. Therefore, an excellent film formation layer cannot be obtained.

Therefore, in order to solve the above-mentioned problems, the appearance of a thin film forming apparatus capable of forming an excellent thin film and a method of driving a shutter used in this apparatus have been desired.

[0012]

Therefore, according to the thin film forming apparatus of the first invention, a shutter is provided between a molecular beam source or a sputter source and a rotary substrate support, and the shutter is opened and closed. A thin film forming apparatus for forming a thin film on a substrate surface mounted on a substrate support,
The rotary shutter includes a columnar body having an opening, and the opening is provided so as to penetrate the columnar body in a direction orthogonal to a rotation axis of the columnar body.

According to the first aspect of the invention, since the columnar rotary shutter is provided with an opening through which the columnar body penetrates, the rotary shutter is rotated by a predetermined rotation angle so that the closed (shielded) state is obtained. The state can be sequentially shifted from an open (open) state or an open state to a closed state. That is,
When the rotation angle of the rotary shutter is 0 degrees, the rotary shutter is in the blocking state. When the rotation angle of the rotary shutter reaches 90 degrees, the shutter is opened, and when the rotation angle of the rotary shutter reaches 180 degrees, the blocking state occurs. As described above, by rotating the rotary shutter from the closed state to the open state, for example, when a molecular beam source is used, an opening (gap hole) through which the molecular beam passes is generated in the shutter opening. Is generated from the center of the opening, that is, the center of the molecular beam source. For this reason, even when the size of the opening of the rotary shutter is small, the molecular beam is distributed over the entire surface of the substrate, so that a uniform thin film is formed on the substrate surface as compared with the related art. be able to.

When the rotary shutter is open,
Since the molecular beam passes through the opening of the rotary shutter, the film-forming substance scattered by molecular beam diffusion is blocked by a shutter shielding surface other than the opening of the rotary shutter, and thus scatters outside the region of the substrate. Molecular beams are limited. Therefore, it is possible to reduce the amount of the film-forming substance that adheres to the inner wall of the chamber of the thin film forming apparatus, the rotation mechanism of the substrate support, or the like. For this reason, the cleaning operation inside the chamber becomes extremely easy.

Further, by rotating the rotary shutter 180 degrees clockwise, the shielding surface of the rotary shutter becomes a face just inverted. For this reason, the amount of substances adhered to one or both shielding surfaces of the rotary shutter is substantially reduced to about 比 べ compared to a conventional single-plate shutter adhered to the same surface. Therefore, according to the present invention, the maintenance period of shutter cleaning can be extended about twice as compared with the related art.

In the present invention, it is preferable that a rotation drive control device for rotating the substrate support and the rotary shutter in synchronization with each other is provided.

As described above, since the rotary drive control device for rotating the substrate support and the rotary shutter in synchronization is provided, the predetermined position of the substrate support and the opening / closing operation of the rotary shutter are synchronized. Thus, the rotary shutter can be opened and closed. That is, the predetermined position of the substrate support and the start position when the rotary shutter moves from closed to open, and the predetermined position of the substrate support and the end position when the rotary shutter moves from open to closed are always Can be in the same position. For this reason, the intensity distribution of molecular beams at the start of film formation and at the end of film formation is more uniform than before, and thus a uniform film formation layer can be formed on the substrate surface.

According to the second aspect of the present invention, when driving a shutter provided between a molecular beam source or a sputter source and a rotary substrate support, the shutter is formed by a rotary type having a column having an opening. A shutter is provided, and an opening is provided so as to penetrate the columnar body in a direction perpendicular to the rotation axis of the columnar body. When the rotary shutter is opened and closed, the substrate supporter is rotated, and the substrate supporter is moved to a predetermined position. When the position reaches the position, the position is detected and the rotary shutter is rotated from the closed state to the open state or from the open state to the closed state in synchronization with the rotation angle of the substrate support.

As described above, the substrate support and the rotary shutter are rotated in synchronization with the predetermined position of the substrate support and the opening / closing operation position of the rotary shutter. The predetermined position of the body and the opening / closing operation position of the rotary shutter can be set to the same position. By setting the predetermined position of the substrate support and the opening / closing operation position of the rotary shutter at the same position at the start of film formation and at the end of film formation, for example, when a molecular beam source is used, fluctuations in the intensity of molecular beams cause film formation. Since the fluctuations are just opposite between the start and the end of film formation,
Fluctuations in molecular beam intensity are mutually offset, and a uniform thin film can be formed on the substrate surface.

[0020]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a thin film forming apparatus according to a first embodiment of the present invention; Here, an example using a thin film forming apparatus having a molecular beam epitaxy (MBE) apparatus and a low-pressure discharge cathode will be particularly described as the thin film forming apparatus. FIGS. 1, 2 and 3 merely show the shapes, sizes and arrangements of the components so that the present invention can be understood.

[Main Configuration of MBE Apparatus of First Embodiment] The main configuration of the MBE apparatus of the first embodiment will be described with reference to FIG. FIG. 1 is a perspective view showing main components of the MBE apparatus.

The MBE apparatus according to the first embodiment includes a molecular beam source 10, a substrate support 16, and a substrate rotating shaft 18 connected to the substrate support 16, as in the prior art.
The substrate rotation shaft 18 is connected to a rotation driving means (not shown) so as to rotate the substrate support 16 at an arbitrary rotation speed.

A heater (not shown) is wound around the molecular beam source (also referred to as a K cell) 10, and the heater is heated to form a film filled in the K cell 10. The material is melted or sublimated to evaporate and molecular beam 2
Generates 0. In the drawing, O indicates the center line of the K cell.

In the first embodiment of the present invention, the rotary shutter 1 comprising a columnar body 12a having an opening 12b is provided between the K cell 10 and the substrate support 16.
Let it be 2. The opening 12b is provided through the column 12a in a direction perpendicular to the rotation axis 14 of the column 12a (FIG. 1). A shutter rotation shaft 14 is connected to the rotary shutter 12, and the shutter rotation shaft 14 is connected to rotation driving means (not shown) to rotate the rotation shutter 12 at a predetermined rotation speed. Can be. Here, the rotary shutter 12 is formed of a cylindrical metal member, and a cylindrical opening 12b is provided in a portion where the molecular beam 20 passes.

The opening 12b of the rotary shutter 12
Is disposed on the center line O of the molecular beam source 10.

In the rotary shutter 12, the opening 12b shifts from an open (open) state to a closed (shielded) state by rotating the shutter rotation shaft 14 by 90 degrees (details will be described later).

At the time of film formation, the shutter rotating shaft 14 is further rotated by 90 degrees. The opening 12b is moved from a position not facing the K cell 10 (shielded state) to a position facing the K cell 10 (open state) by the rotation of the shutter 12, so that the molecular beam 20 from the K cell 10 After reaching the surface of a substrate (not shown) mounted on the substrate support 16 through the opening 12b, a film formation layer can be formed by the molecular beam 20.

Next, referring to FIGS. 2A to 2D,
How the shutter is opened when the rotary shutter of the present invention is rotated from the closed state to the open state will be described. (A), (B), (C) and (D) of FIG. 3 schematically illustrate how the opening state of the opening changes when the rotary shutter is rotated from the closed state to the open state. FIG. In addition, (A) of FIG.
(B), (C) and (D) show the center 11 of the molecular beam source.
FIG. 6 shows a state as viewed from above in an extension of (corresponding to the center line O of the K cell 10). Also, the hatched lines drawn in the figure do not represent cross sections, but are lines added to clarify constituent components.

First, the rotary shutter 12 is set in a state where it is shielded from the direction of the center portion 11 of the molecular beam (FIG. 2A). Now, let us suppose that the opening end on the right side of the opening is indicated by R and the opening end on the left side is indicated by L in the diagram of FIG.

Next, when the shutter rotating shaft 14 is sequentially rotated clockwise (or counterclockwise) from the closed state of 0 degrees, the opening area of the opening 12b (the opening area I in FIG. And the opening area II) of FIG. 2C gradually increases. These opening regions I and II are formed such that a right opening end R and a left opening end L overlap in a peripheral region around the center line O of the K cell 10. When the rotation angle of the shutter rotation shaft 14 becomes 90 degrees, the opening ends R and L completely overlap, and the opening 12b is opened (the opening region III in FIG. 2D).

FIGS. 2A, 2B, 2C and 2D
As can be understood from FIG.
2 is opened from the center part 11 of the molecular beam source 10, so that even if the opening area of the opening 12b of the rotary shutter 12 is small (the opening area I in FIG. 2B), the molecular beam 20 It passes through the opening region I and is distributed over the entire surface of the substrate (not shown). For this reason, unlike the conventional case, the film formation does not start unless the single-plate shutter is opened above the center of the molecular beam source 10, whereas in the present invention, the molecular beam is distributed over the entire substrate when the opening region appears. Thus, a uniform thin film can be formed on the substrate surface at the initial stage of the rotation of the shutter.

When the rotary shutter 12 is open, the molecular beam 20 is moved to the opening 1 of the rotary shutter 12.
Since the light passes through the second shutter 2 b, the molecular beam (not shown) diffusing to the area other than the opening 12 b is shielded by the shield surface 13 of the rotary shutter 12. Therefore, in this embodiment, diffusion of molecular beams scattered other than on the substrate can be restricted. For this reason, a film-forming substance is deposited on the inner wall of a chamber (not shown), and an unnecessary gas reacts with the film-forming substance to form impurities, or the film-forming substance is peeled off, thereby deteriorating the film-forming environment. Therefore, the operation of cleaning the inner wall of the chamber becomes extremely easy, and the film forming characteristics can be improved.

Further, in the present invention, the molecular beam 20 is opened or shielded each time the rotary shutter 12 rotates 90 degrees. Therefore, the shielding surface of the rotary shutter 12 is replaced by the rotation of 180 degrees, and a new shielding is performed. Surface (not shown). Therefore, according to the present invention, the adhesion area (shielding area) of the molecular beam is about twice as large as that of the conventional single-plate shutter on both sides. , About ２. Therefore, the maintenance period such as cleaning of the rotary shutter 12 can be extended about twice as long as the conventional one.

Next, an embodiment using a sputter source instead of a molecular beam source will be described with reference to FIG. FIG. 3 is a perspective view showing a configuration example using a low-pressure discharge cathode as a sputter source.

In this embodiment, a low pressure discharge cathode 22 is used as a sputter source. The low-pressure discharge cathode 22 includes a cathode unit, a target mounted on the cathode unit, and an anode unit (none is shown) disposed above the cathode unit. By applying a high frequency voltage to the cathode portion of the low pressure discharge cathode 22 and performing sputtering in any suitable gas atmosphere, atoms or molecules are generated from the low pressure discharge cathode 22. The atoms or molecules are passed through the opening 12b of the rotary shutter 12 to form a film on the upper surface of a substrate (not shown) mounted on the upper surface of the substrate support 16. Note that the method of opening and closing the rotary shutter 12 in the case of using a sputter source is exactly the same as in the case of the molecular beam source described above, and a description thereof will be omitted here.

[Main Configuration of MBE Apparatus According to Second Embodiment] Next, referring to FIG. 4, the MBE apparatus according to the second embodiment will be described.
The main configuration of the device will be described. In the second embodiment,
This is an example in which a rotation drive control device is added to the MBE device of the first embodiment.

The rotation drive control device 100 of the present invention comprises a rotation angle detection means 102, a rotation control means 106, and a rotation drive means 108. Further, the rotation angle detecting means 102 includes a position detector 103 and a position detecting circuit 10.
4.

The substrate rotation shaft 18 is connected to a rotation driving means 200 similar to the conventional one, and can rotate the substrate support 16 at an arbitrary rotation speed.

The rotation driving means 200 for rotating the substrate support 16 is driven by a rotation transmission mechanism (not shown) for transmitting rotation in the atmosphere to rotation in a vacuum and a motor (not shown). It is configured.

The rotation angle detecting means 102 of the present invention comprises a position detector (for example, a potentiometer) 103 for detecting a voltage change according to the rotation angle and a position detection circuit 104. Note that a position detector such as an encoder that outputs a pulse signal according to the rotation angle may be used instead of the potentiometer.

The rotation control means 106 includes an arithmetic processing unit (not shown), converts the position signal and the rotation angle output signal of the rotation angle detection means 102 into control signals, and converts the control signals into rotation driving signals. This is output by the means 108.

The rotation driving means 108 includes a rotation transmission mechanism (not shown) for transmitting rotation in the atmosphere to rotation in a vacuum, and a motor (not shown).

[Method of Driving Shutter of Second Embodiment] Next, a method of driving a shutter of the second embodiment will be described with reference to FIGS. In addition, FIG.
FIG. 3 shows a perspective view illustrating a configuration of an MBE device according to a second embodiment and a block diagram of a rotation drive control device for driving a rotary shutter. FIG. 5 is a diagram for explaining the relationship between the rotation angle of the substrate support and the operation of opening and closing the shutter. The horizontal axis indicates the rotation angle (degree) of the substrate support, and the vertical axis indicates the open / closed state of the rotary shutter. Take and show. Hereinafter, the M of the second invention
The shutter driving method of the BE device will be described in detail with reference to FIGS.

First, the opening 12b of the rotary shutter 12
Is set to the shielded state. Then, the rotation driving means 200
The motor (not shown) is driven to rotate the substrate rotation shaft 18. At this time, the substrate support 16 connected to the substrate rotation shaft 18 also rotates at the same time.

Next, a predetermined position S of the substrate support 16 is detected by outputting a voltage corresponding to the rotation angle by using the rotation angle detecting means 102, for example, a potentiometer 103.

The rotation control means 106 converts the position signal and the rotation angle output signal of the rotation angle detection means 102 into control signals, for example, on / off signals, and outputs them to the rotation drive means 108. In this manner, by turning on / off the rotation driving unit 108, the rotary shutter 12 can be rotated or stopped.

As can be understood from FIG. 5, the predetermined position S of the substrate support 16 is, for example, rotated once (360 degrees) to return to the original position.
02, and the rotary shutter 12 is rotated in synchronization with the predetermined position S. At this time, if the rotary shutter 12 is rotated by 90 degrees, the substrate is in the open state. Therefore, the predetermined position S of the substrate support 16 is also 90 degrees clockwise, that is, the predetermined position S of the substrate support 16 before starting driving. 450 degrees in terms of rotation angle from the position ((360 + 90) degrees)
(The position S in FIG. 4).

Thereafter, the rotary shutter 12 is stopped,
A film is formed by generating a molecular beam on the substrate surface while rotating the substrate support 16.

Next, when the film formation is completed, the predetermined position S of the substrate support 16 is set to 360N + S (where N is the number of rotations) (degrees), that is, 360N + 90 here.
At the position of (degree), the rotary shutter 12 is rotationally moved so that the opening 12b of the rotary shutter 12 is closed.

As described above, according to the present invention, when the rotary shutter 12 is opened and closed, the substrate support 16 in the open state is opened.
And the predetermined position of the substrate support 16 in the closed state are always driven to the same position. Therefore, the fluctuation of the molecular beam intensity due to the opening and closing of the shutter is exactly the same between the open state and the closed state. The fluctuation is opposite, and the fluctuation of the molecular beam intensity due to the opening and closing of the rotary shutter 12 can be offset. Therefore, in the present invention, compared with the conventional shutter opening / closing operation,
The variation of the molecular beam becomes uniform, so that an excellent film-forming layer can be formed on the substrate surface.

[0051]

As is apparent from the above description, according to the thin film forming apparatus of the present invention and the method of driving the shutter used in the apparatus, the molecular beam is moved to the center of the opening area, that is, the opening of the rotary shutter. Since it is generated from the center of the molecular beam source, the intensity distribution of the molecular beam on the substrate surface becomes uniform by slightly rotating the rotary shutter. Therefore,
When a monoatomic layer is formed, even if the film formation time from the open state to the closed state of the shutter is short, fluctuations in molecular beam intensity due to opening and closing of the rotary shutter are reduced, so that excellent film formation on the substrate surface is achieved. Layers can be formed.

Further, at the time of film formation, since the molecular beam passes through the opening of the rotary shutter to form the film, scattering of the film-forming substance due to diffusion of the molecular beam is suppressed, and the molecular beam adheres to an area other than the substrate. Film materials can be reduced. For this reason, maintenance work is simplified and productivity is improved.

Further, by rotating the rotary shutter to the shielding state, the shielding surface is about twice as large as the conventional one, so that the film-forming substance adhering to one or both shielding surfaces is substantially reduced. It can be reduced to 1/2. For this reason,
The maintenance period of the rotary shutter can be extended more than before.

[Brief description of the drawings]

FIG. 1 shows a molecular beam epitaxy (MB) according to a first embodiment.
E) It is a perspective view provided for explaining the main configuration of the device.

FIGS. 2A to 2D show MBE according to the first embodiment;
FIG. 4 is a diagram for explaining a shutter operation of the device.

FIG. 3 is a perspective view for explaining a main configuration of an apparatus using a low-pressure discharge cathode according to the first embodiment.

FIG. 4 shows a molecular beam epitaxy (MB) according to a second embodiment.
E) It is a perspective view provided for explaining the main configuration of the device.

FIG. 5 is a diagram for explaining a relationship between a substrate support member rotation angle and a shutter opening / closing operation.

[Explanation of symbols]

 10: Molecular beam source 11: Center part of molecular beam source 12: Rotary shutter 13: Shielding surface 14: Shutter rotation axis 16: Substrate support 18: Substrate rotation axis 20: Molecular beam 22: Sputter source source 24: Atomic or Molecule 100: rotation drive control device 102: rotation angle detection means 103: position detector 104: position detection circuit 106: rotation control means 108: rotation drive means

Claims (5)

[Claims] 1. A shutter is provided between a molecular beam source or a sputter source and a rotary substrate support, and the shutter is opened and closed to form a thin film on a substrate surface mounted on the substrate support. In the thin film forming apparatus, the shutter may be a rotary shutter including a column having an opening, and the opening may be provided to penetrate the column in a direction orthogonal to a rotation axis of the column. Characteristic thin film forming equipment. 2. The thin film forming apparatus according to claim 1, further comprising a rotation drive control device for rotating the substrate support and the rotary shutter in synchronization with each other. . 3. The thin film forming apparatus according to claim 2, wherein the rotation drive control device includes a rotation angle detection unit for detecting a predetermined position of the rotating substrate support, and a position of the rotation angle detection unit. Rotation control means for converting a signal into a control signal to control the rotary shutter, and rotation drive means for receiving a control signal from the rotation control means and controlling the rotation of the rotary shutter. A thin film forming apparatus. 4. When driving a shutter provided between a molecular beam source or a sputter source source and a rotary substrate support, the shutter is a rotary shutter composed of a columnar body having an opening, The opening is provided so as to penetrate the columnar body in a direction orthogonal to the rotation axis of the columnar body. When the rotary shutter is opened and closed, the substrate supporter is rotated and the substrate supporter is positioned at a predetermined position. Detecting the position and rotating the rotary shutter from a closed state to an open state or from an open state to a closed state in synchronization with the rotation angle of the substrate support; How to drive the shutter. 5. The method of driving a shutter according to claim 4, wherein at the start of film formation, the rotary shutter is rotated by synchronizing a predetermined position of the substrate support with a shielding position of the rotary shutter. A method of driving a shutter for use in a thin film forming apparatus, comprising: synchronizing a predetermined position of the substrate supporter with an opening position of the rotary shutter when the film is completed, and rotating the rotary shutter.