JPH0515674B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a mass-produced molecular beam epitaxy apparatus that is constructed so that the degassing time of a growth chamber for each growth cycle for a substrate can be significantly shortened or omitted.

[Conventional technology]

Molecular beam epitaxy is attracting attention as a method for epitaxially growing - group elements on a single crystal substrate in the process of manufacturing - group compound semiconductors. This is a type of vacuum evaporation method,
Group elements such as gallium Ga, aluminum Al, and indium In, as well as group elements such as elemental As and phosphorus P, are used as growth materials and are irradiated in the form of atomic or molecular beams in an ultra-high vacuum of 10 ^-11 torr. Ga
Ga As, Al Ga on single crystal substrates such as As and In P
This is a method of epitaxially growing - group compound semiconductor crystals such as As, InP, and InGaAsP. According to this molecular beam epitaxy method,
Because the deposition is performed in an ultra-high vacuum, there is very little contamination of impurities from residual gas, and it is possible to obtain a uniform and flat film at the atomic level over a large area, keeping the substrate surface clean. can,
Because the deposition rate can be extremely slow and precisely controlled, multi-component mixed crystal thin films can be created by simply increasing the number of evaporation sources. easily obtained,
It is possible to obtain various information about the growth conditions from the surface of the growth layer or from the molecular beam during crystal growth, and to enjoy the advantages that this information can be immediately fed back to growth control. First, an overview of a conventional molecular beam epitaxy apparatus and a crystal growth method using the apparatus will be explained. FIG. 13 shows a growth chamber 2, which is the central device of the molecular beam epitaxy apparatus, and is connected to an ultra-high vacuum pump 1. In the center of the growth chamber, a substrate support 3 whose rotation can be controlled around the axis of the growth chamber is arranged. A plurality of substrates B placed on the substrate and carried into the growth chamber are mounted by a manipulator or the like. The reason why the substrate support 3 can be controlled in rotation is to make the crystal growth on the substrate uniform. Further, a heater (not shown) is provided to raise the temperature of the substrate supported by the substrate support 3 to a desired temperature. The above board support tool 3
On one side of the growth chamber opposite to the growth surface of the substrate B mounted on the substrate support 3, the axes a, b... Tilted evaporation sources 5a, 5b
... are arranged in an annular shape centered on the axis l of the growth chamber 2, and so that the distances from the center of the substrate B mounted on the substrate support are approximately equal. Each evaporation source 5a, 5b... is constructed by filling a crucible 4... opening toward the center of the substrate B with each growth material. The temperature is now being raised to . In addition, each evaporation source 5a,
5b... are placed in a liquid nitrogen shroud 6 so that they are not affected by heat or contamination from other evaporation sources.
surrounded by The start and stop of crystal growth is
This is performed by opening and closing shutters 7 placed at the openings of each crucible 4. For example, to grow a GaAs layer on a GaAs single crystal substrate, a Ga-filled evaporation source and
The evaporation source filled with As is heated to a predetermined temperature, the temperature of the substrate is set to an appropriate temperature, and the shutters 7 of each of the evaporation sources are controlled to be open for a predetermined period of time. Note that at this time, Al
When evaporated together, a Ga _x Al _1-x layer grows.
If the ratio of the evaporation amount of Ga and Al at this time is controlled,
The composition x can be controlled. Also, to make the growth layer n-type, Si, Sn, etc. are evaporated at the same time, and to make it p-type, Be, Mg, etc. are grown simultaneously.

[Problem to be solved by the invention]

By the way, it is being considered that the above-mentioned molecular beam epitaxy equipment, which has been mainly used in laboratories or laboratories, will be mass-produced for compound semiconductors. It is necessary to automate the loading and unloading of materials. As a method for loading and unloading the substrate, as shown in the schematic configuration in FIG. A transfer chamber or substrate preparation chamber 10 equipped with a second gate valve 9 that can be vacuum isolated from the substrate holder H in the external atmosphere is provided.
This substrate holder H holds a plurality of substrates.
The first gate valve 8 is closed to maintain an ultra-high vacuum inside the growth chamber, and the second gate valve 9 is opened to transport the substrate into the substrate preparation chamber 10, and the second gate valve 9 is closed to prepare the substrate. A method has been considered in which the chamber 10 is evacuated to the same degree of vacuum as the growth chamber 2, the first gate valve 8 is opened, the material is carried into the growth chamber, and the first gate valve 8 is closed. . In this way, there is no need to increase or decrease the pressure in the growth chamber each time the substrate is replaced, and continuous operation is possible. Note that, in order to carry out the crystal-grown substrate from the growth chamber, the substrate is carried out in a completely reverse procedure to that described above. However, even if the method for carrying the substrate into the growth chamber as described above is adopted, the following problem still remains. That is, although a molybdenum block made of molybdenum or a molybdenum alloy is used as the substrate holder H for mounting a plurality of substrates because of its excellent strength, stability at high temperatures, and corrosion resistance, Since the substrate holder H moves from the atmosphere to a growth chamber that requires an ultra-high vacuum and remains within the growth chamber, moisture, air, or other contaminants attached to the surface of this substrate holder H are removed from the growth chamber. There is no guarantee that the gas can be completely degassed, and even if these sources of contamination were to be removed by degassing, it would take a very long time to ensure safety. This invention was devised under the above-mentioned circumstances, and facilitates degassing of a substrate holder loaded with a substrate and carried into a growth chamber, thereby minimizing contamination of the growth chamber by the substrate holder. can be controlled,
The purpose of the present invention is to provide a molecular beam epitaxy device that enables efficient continuous operation.

[Means to solve the problem]

In order to solve the above-mentioned conventional problems, the present invention takes the following technical measures. That is, the molecular beam epitaxy apparatus of the present invention includes a growth chamber that is capable of ultra-high vacuum depressurization and has a substrate support for supporting a substrate held by a substrate holder, and a first A substrate preparation chamber connected via a gate valve and capable of vacuum reduction; and a substrate loading chamber connected to the substrate preparation chamber via a second gate valve, capable of vacuum reduction and having a substrate loading port. The substrate loading chamber is reciprocally movable from a substrate receiving position therein to a substrate transfer position in the substrate preparation chamber through the second gate valve in an open state; A first transfer tray for placing and holding a substrate is provided in the substrate preparation chamber, and a substrate holder for holding a substrate is placed in the substrate preparation chamber, and the substrate is transferred from the substrate transfer position through the first gate valve in an open state. A second transport tray that can be moved back and forth to the substrate support in the growth chamber, and a substrate holder on the first transport tray that is at the substrate transfer position and the second transport tray that is also at the substrate transfer position. A substrate transfer mechanism is provided for transferring the substrate, and the substrate support in the growth chamber is configured to transfer the substrate holder to and from the second transport tray that has been moved into the growth chamber. It is characterized by

[Effect]

To carry the substrate into the growth chamber, the substrate loaded on the first transport tray in the substrate loading chamber is transferred onto the substrate holder on the second transport tray waiting in the substrate preparation chamber.
The second transfer tray on which the substrate holder with the substrate transferred in this manner is placed enters the growth chamber. The substrate loading chamber is depressurized after the substrates are loaded onto the first transport tray at the loading position. Then, the second gate valve is opened and the first transfer tray moves to the substrate transfer position in the substrate preparation chamber. At this point, the substrate transfer mechanism transfers the substrate on the first transfer tray to the substrate holder on the second transfer tray.
When this transfer is completed, the first transfer tray is retreated to the substrate loading chamber, and the second gate valve is closed. Then, when the pressure in the substrate preparation chamber is further reduced, the first gate valve is opened and the growth chamber and the substrate preparation chamber are brought into communication. The second transport tray transports the substrate holder into the growth chamber through the first gate valve, and the substrate holder is attached to a substrate support within the growth chamber. Next, this second transport tray is evacuated to the substrate preparation chamber, the first gate valve is closed, and crystal growth on the substrate is started after predetermined preparations in the growth chamber, which is completely isolated from the outside. . The substrate after crystal growth is carried out from the substrate loading chamber by the reverse procedure to the above.

【Effect of the invention】

As described above, in the molecular beam epitaxy apparatus of the present invention, there is no member other than the substrate that enters the growth chamber from the atmosphere. For example, a substrate holder that holds a substrate and is mounted within the growth chamber is simply moved between the substrate preparation chamber and the growth chamber under reduced pressure. Furthermore, the first transport tray, which comes into contact with the atmosphere during the substrate transport process, only moves between the substrate loading chamber and the substrate preparation chamber, and does not enter the growth chamber. Moreover, this movement is performed under reduced pressure. Therefore, contamination of the growth chamber by external contamination sources can be greatly reduced, and degassing in the growth chamber is easy and takes only a short time, allowing more efficient operation of the apparatus.

[Explanation of Examples]

Embodiments of the present invention are shown in FIGS. 1 to 12 below.
This will be explained in detail with reference to the drawings. In these figures, members or parts that are equivalent to those of the conventional example are given the same reference numerals. As shown in plan in FIG. 1, the molecular beam epitaxy apparatus of the present invention includes a growth chamber 2 in which crystal growth is performed on a substrate B, and a growth chamber 2 connected to the growth chamber 2 via a first gate valve 8. Board preparation room 10
and a substrate loading chamber 11 connected to the substrate preparation chamber 10 via a second gate valve 9. These will be explained in detail below. FIG. 2 shows a longitudinal section of the growth chamber 2. The basic structure of the growth chamber 2 of this example is the same as that of the conventional example shown in FIG. The growth chamber 2 has a vertical cylindrical shape as a whole, and a support shaft 19 is supported through the ceiling plate 12.
Attached to the growth chamber 2 in FIG. 1 is a cage-shaped substrate support 3 having substrate holder placement parts 13, 13 in the form of inward flanges facing each other at a constant interval, as shown by imaginary lines. . Returning to FIG. 2, a boss portion 14 is formed at the top of the substrate support 3, and this boss portion 14 is rotatably fitted to the lower end of the support shaft 19. The rotation of the board support 3 is controlled by meshing a pinion 17 of an output shaft of an external motor 16 with a gear 15 fixed to a boss part 14. Actuator 1 provided
By moving the support shaft 19 forward and backward by means of 8, it is possible to move the support shaft 19 up and down a certain distance. This is to transfer the substrate holder H on which the substrate B is placed from the second transport tray 24 inserted into the growth chamber 2 from the substrate preparation chamber 10, which will be described later, and this will be described later. Note that a heater 20 is provided at the tip of the support shaft 19 and is located behind the substrate holder H or the substrate B supported by the substrate support 3, thereby heating the substrate B to a desired temperature. sell. The inner periphery of the side wall of the growth chamber 2 is surrounded by a liquid nitrogen shroud 21, which adsorbs impurities during degassing and maintains an ultra-high vacuum. In addition, an ultra-high vacuum pump (not shown) is connected to this growth chamber, and thereby the growth chamber 2
can be reduced to ultra-high vacuum. The bottom of the growth chamber 2 has a nearly concave shape with the center being the most concave, and several evaporation sources 5 are placed in this part.
a, 5b, 5c, . . . are arranged such that their axes a, b, c, . . . face the center of the substrate holder H held by the substrate support 3. In this example, arsenic
Evaporation source 5a using Group V elements such as As as a growth material
is arranged so as to face the substrate holder H, that is, this evaporation source 5a is arranged to coincide with the vertical center line of the growth chamber 2, and the other evaporation sources 5b and 5c are arranged so as to face the substrate holder H. They are arranged in a ring shape centered on the axis a of the evaporation source 5a. In order to avoid complication in the diagram, only two evaporation sources 5b and 5c facing each other across the group V evaporation source 5a are shown in FIG. 2, but in reality, there are 5 to 7 evaporation sources of various sizes. , are arranged in a ring shape with each axis facing the center of the substrate support 3. Each of the evaporation sources 5a, 5b, and 5c is placed in a bottomed cylindrical container whose upper end is fixed to the bottom wall of the growth chamber 2.
It is constructed by loading crucibles 4 each filled with each growth material. And each evaporation source 5a, 5
The crucibles 4 b and 5c are heated to a desired temperature by a heater (not shown) provided in the container in which they are housed. Further, a liquid nitrogen shroud 6 is integrally formed in the container surrounding each crucible 4, and each evaporation source 5a, 5b, 5c
... are made so that they are not affected by heat or pollution from each other. When the growth chamber 2 is placed in an ultra-high vacuum state and the substrate B and each evaporation source 5a, 5b, 5c... are heated to a predetermined temperature, the growth material in the evaporation source 5a, 5b, 5c... becomes atomic or molecular beam. crystals contact the substrate surface and grow on the substrate B, but the start and stop of this growth is controlled by each evaporation source 5b, 5c...
This is done by opening and closing the opening of the shutter 7 with the shutter 7. This shutter 7 has shafts 7a each inserted into the inner wall of the growth chamber so as to be rotatably controllable from the outside.
A shutter plate 7b that can cover the openings of the evaporation sources 5b and 5c in the closed position is fixed to the tip of the shutter plate 7b. Now, the above substrate holder H is shown in FIGS. 4 and 5.
As shown in the figure, seven disc-shaped substrates B are mounted on a thin disc made of molybdenum or molybdenum alloy.
It has a shape in which seven holding holes 22 are regularly opened into which the holding holes 22 can be inserted and held downward. Note that the notches 22a provided at three locations in each holding hole 22 are provided with the claws 2 of the transfer mechanism 28, which will be described later.
8b is for escape. The substrate B is placed on the first transport tray 23 in the substrate loading chamber 11, held on the substrate holder H in the substrate preparation room 10, and grown on the second transport tray 24 while being placed on the substrate holder H. It is carried into room 2. As explained before, in the above-mentioned growth chamber 2,
A substrate preparation chamber 10 is connected via a first gate valve 8 , and a substrate loading chamber 11 is further connected to this substrate preparation chamber 10 via a second gate valve 9 . The substrate preparation chamber 10 has a cylindrical shape and is horizontally connected to the side wall of the growth chamber 2 at a position corresponding to the height of the substrate support 3.
1 has a cylindrical shape that is perpendicular to the cylindrical substrate preparation chamber 10 and connected to extend in the horizontal direction. First transport tray 2 arranged in substrate loading chamber 11
The details of No. 3 are shown in plan in FIG. The base of the first transport tray 2 is connected to a support rod 25 that moves back and forth in the axial direction of the substrate loading chamber 11 by an external actuator (not shown), and the substrate holder H
The three rows of accommodation holes 26 arranged in the direction in which the support rod 25 advances and retreats are grooves of a predetermined width that are open in the direction in which the support rod 25 advances. They are connected by 27... This relief groove 27 is for escaping the post 28a of the transfer mechanism 28 disposed in the substrate preparation chamber 10, and will be described later. In addition, three notches 26a are formed in each storage hole 26 at equal intervals, but these are to allow the claws 28b of the transfer mechanism 28 to escape, and this also applies. This will be explained later. The first transport tray 23 is capable of reciprocating between a substrate receiving position shown by a solid line in FIG. 1 and a substrate transfer position shown by a phantom line in FIG. The substrate transfer position coincides with the substrate transfer position of the second transport tray 24 moving within the substrate preparation chamber 10 in plan view, and is aligned with the axis of the substrate preparation chamber 10 and the substrate loading chamber 11.
It is located on the intersection of the axes of . As shown in FIG. 3, a board loading port 29 that can be hermetically sealed is provided on the upper surface of the board loading chamber 11 corresponding to the first transport tray 23 at the board receiving position. The substrate B is fitted and loaded into each accommodation hole 26 of the transport tray 23 with the growth surface facing downward. Further, in FIG. 3, reference numeral 30 indicates an exhaust port, which allows the substrate loading chamber 11 to be evacuated. Second transport tray 2 arranged in the substrate preparation room 10
4 is shown in detail in FIGS. 7 and 8. This tray 24 is attached to the tip of a slide rod 32 that is slid back and forth in the axial direction of the substrate preparation chamber 10 by a slide device 31 (see FIGS. 1 and 9) disposed at one end of the substrate preparation chamber 10. The opposite periphery of the disc is attached to the slide rod 3 above.
2, and as is clear from a comparison with FIG. A through hole 33 is opened. Furthermore, an upright wall 34 that fits and holds the outer periphery of the substrate holder H is formed on an arcuate peripheral edge portion of the slide device 31 that faces in the axial direction. Then, when the second transport tray 24 is at the transfer position, the substrate holder H is fitted and held in principle. Note that the opposite circumferential portions of the second transport tray 24 are removed in a chord shape as described above because the pair of substrate holder mounting portions 13 and 13 are arranged opposite each other in the substrate support 3 in the growth chamber 2. This is to allow the second transport tray 24 to enter in between.
The through holes 33 are for accommodating the posts 28a of the transfer mechanism 28, and the three notches 33a provided in each through hole 33 are for accommodating the posts 28a of the transfer mechanism 28.
Similarly to the holding holes 22 and accommodation holes 26 of the first transport tray 23, the claws 28 of the transfer mechanism 28
This is to allow b to escape. The second transport tray 24 is capable of reciprocating movement from the transfer position to the inside of the growth chamber 2 through the first gate valve 8. The first transport tray 2 in the substrate preparation room 10
Below each substrate transfer position of 3 and the second transport tray 24, there is a substrate holder H on the second transport tray 24.
A substrate transfer mechanism 28 for transferring the substrate B is provided between the first transfer tray 23 and the first transfer tray 23 . As shown in FIG. 3, this substrate transfer mechanism 28 has a circular base plate 36 attached to the upper end of a support shaft 35 that extends from the bottom wall of the substrate preparation chamber 10 into the chamber so as to be able to slide vertically. , on the top surface of this base plate 36,
The first transport tray 23 in the substrate transfer position, the substrate holder H supported by it, and the second transport tray 2
Seven posts 28a are provided to correspond to the respective holding holes 22 to through holes 33 of the four holding holes 28a.
As shown in detail in FIG. 1, each post 28a is provided with three claws 28b at the upper end thereof, which can hook and hold the substrate B at three locations around it. As mentioned before, each holding hole 22 of the first transport tray 23, the second transport tray 24, and the substrate holder H
The notch formed at the periphery of the through hole 33 is
This corresponds to the planar arrangement of the claws 28b at the upper ends of each post 28a described above. Therefore, when the first transport tray 23, the second transport tray 24, and the substrate holder H overlap in plan view, each post 28
The claw 28b of a can pass through each of the above notches in the vertical direction. As shown in FIG. 3, the vertical positional relationship between the first transport tray 23 and the second transport tray 24 at the substrate transfer position is such that the first transport tray 23 is above the second transport tray 24. Further, in the normal state, the transfer mechanism 28 is moved downward so that each claw 28b is sunk below the second transport tray 24, as shown by imaginary lines in FIG. The transfer mechanism 28 can be controlled to move up and down between the depressed position and the substrate lifting position where each claw 28b projects upward from the first transport tray 23. The substrate B is transferred from the first transport tray 23 to the substrate holder H on the second transport tray 24 by the transfer mechanism 28.
The transfer is performed as follows. While the substrate transfer mechanism 28 is in the sunken position, the first transport tray 23 that holds the substrate B and the second transport tray 24 that holds the substrate holder H take their respective transfer positions, and then the transfer begins. Mechanism 28
The claws 28b move upward to catch the periphery of each substrate B and lift it further upward from the first transport tray 23, as shown in FIG. next,
The first transport tray 23 is retracted and returned to the substrate receiving position in the substrate loading chamber 11. As explained above, the three rows of accommodation holes 26 lined up in the moving direction of the first transport tray 23 are connected by the escape groove 27 that escapes the post 28a, so that the transfer device 28 is not moved upward. Therefore, the first transport tray 23 can be retracted without any problem. Next, the claws 28b of the transfer mechanism 28 are lowered, and each substrate B that was hooked by the claws 28b is transferred to the substrate holder H on the second transport tray 24.
It fits into each holding hole 22 and is held. Also, contrary to the above, the crystal-grown substrate B held on the substrate holder H on the second transport tray 24
To transfer the paper to the first transport tray 23, the procedure is reversed to the above. That is, when the second transport tray 24 on which the substrate holder H holding the crystal-grown substrate B is placed reaches the transfer position, the substrate transfer mechanism 28
The claw 28b lifts the first transport tray 23 to a lifting position above the movement trajectory and waits for the first transport tray 23 to arrive at the transfer position. Then, when the first transport tray 23 reaches the transfer position, the substrate transfer mechanism 28 moves downward, and each substrate B, which was lifted by the claw 28b at this time, is transferred to the first transport tray 23.
It is held in the accommodation hole 26 of. Now, the substrate holder H, which has received the ungrown substrate B from the first transport tray 23 in the substrate preparation chamber 11 as described above, is placed on the second transport tray 24 and carried into the growth chamber 2. Yes, but
In this embodiment, between the substrate transfer position of the second tray 24 in the substrate preparation room 11 and the growth chamber 2, the substrate B is preheated and degassed in advance, and the substrate B or the substrate holder is H
A preheating device 37 having a stock function is provided. This preheating device 37 is shown in FIG.
As shown in FIG. 2, the substrate preparation chamber 11 is equipped with a stocker 39 having a plurality of shelves 38 spaced at equal intervals in the vertical direction and capable of supporting the periphery of the substrate holder H by controlling its movement in the vertical direction. It is arranged and configured within. The vertical axis of the stocker 39 is made to intersect with the axis of the substrate preparation chamber 11, that is, with the movement locus of the second transport tray 24, and
The intervals between the shelves 38 are determined so that the second transport tray 24 carrying the substrate holders H can pass therebetween. However, each shelf 38 is shaped so that it interferes with the substrate holder H in the vertical direction, but does not interfere with the second transport tray 24 in the vertical direction. To place the substrate holder H on the shelf 38 of the stocker 39, position the stocker 39 so that the shelf 38 on which it should be placed is slightly below the movement trajectory of the second transport tray 24, and place the board holder H on the shelf 38 and one of the shelves. The second transport tray 24 with the substrate holder H placed thereon is introduced into the gap between it and the upper shelf, and the stocker 39 is moved upward. Conversely, any shelf 38 of the stocker 39
The substrate holder H placed on the second transport tray 24
For loading, the shelf 38 is placed on the second transport tray 2.
Move the stocker 3 so that it is slightly above the movement trajectory of 4.
9, the second conveyance tray 24 is introduced into the gap between this shelf 38 and one of the shelves below it, and the stocker 39 is moved downward. Note that in FIG. 10, reference numeral 40 is a heater for preheating the substrates B stored in the stocker 39. In addition, in FIG.
indicates an exhaust port, which allows the substrate preparation chamber 10 to be depressurized to a high vacuum. Substrate holder H placed on second transport tray 24
is introduced into the growth chamber 2 and held on the substrate support 3 in the following manner. As explained before, in FIG. 2, the substrate holder 3 within the growth chamber 2 can be controlled to move up and down, and more specifically, the substrate holder placement parts 13, 1
3 can be controlled to reciprocate up and down between a position slightly below and a position slightly above the movement locus of the second transport tray 24 within the growth chamber. Further, this substrate support 3 is rotatable around the support shaft 19, but when the second transport tray 24 is introduced and receives the substrate holder H placed thereon, each of the opposing substrate holder placement parts The rotational position of the second transport tray 24 is determined so that the second transport tray 24 is parallel to the movement axis of the second transport tray 24 . In this state, each substrate holder mounting section 13, 13 is placed on the second transport tray 24.
Although it interferes with the upper substrate holder H in the vertical direction, it does not interfere with the second transport tray itself 24 in the vertical direction. The substrate support 3 has its respective substrate holder placement parts 1
3 and 13 are positioned so that they face each other across the moving direction line of the second transport tray 24,
It takes the lower position and waits for the second transport tray 24 to be introduced. Then, when the second transport tray 24 is introduced,
The substrate support 3 moves upward and the substrate holder placement part 1
3 and 13 catch the periphery of the substrate holder H and lift it up. After the transfer of the substrate holder H, the second transport tray 24 retreats to the substrate preparation room 11. Next, the overall operation of the device of the present invention will be explained. First, an example of a procedure for carrying the substrate B before growth into the growth chamber 2 will be described. At this stage, the growth chamber 2 is in an ultra-high vacuum state in preparation for crystal growth, and the substrate preparation chamber 10 is also in a high vacuum state. The first gate valve 8 that isolates the growth chamber 2 and the substrate preparation chamber 10 and the second gate valve 9 that isolates the substrate preparation chamber 10 and the substrate loading chamber 11 are both in a closed state. In the substrate loading chamber 11, the first transport tray 23 is
Located at the board receiving position, board B, board loading port 2
9 into each accommodation hole 26 of the first conveyance tray 23 and is supported. Next, the substrate loading port 29 is closed, and the pressure in the substrate loading chamber 11 is reduced to the same level of vacuum as the substrate preparation chamber 10. Next, the second gate valve 9 is opened to communicate the substrate preparation chamber 10 and the substrate loading chamber 11, and the first transfer tray 23 is transferred to and from the substrate preparation chamber 10 through the second gate valve 9. Advance to the position. In the substrate preparation room 10, the stocker 3 of the preheating device 37
The second transport tray 24 on which empty substrate holders H have been loaded from the shelf 38 of No. 9 is waiting at the substrate transfer position.
Then, the substrate transfer mechanism 28 operates as described above, and the substrate B on the first transport tray 23 is transferred and held in the holding hole 22 of the substrate holder H on the second transport tray 24. The first transport tray 23 is retracted and returned to the substrate receiving position within the substrate loading chamber 11, and the second gate valve 9 is closed. At this time, the board loading chamber 1
1, substrates are subsequently loaded onto the first transport tray 23. In the substrate preparation room 10, the second transport tray 24 on which the substrate holder H holding the substrate B was transferred as described above advances to the preheating device 37, and the substrate holder is placed on a predetermined shelf 38 of the stocker 39. It is loaded as described above. In this way, all the empty substrate holders H on the shelf 38 of the preheating device 37 are placed on the second transport tray 24 and transported to the substrate transfer position, and then the substrates B are transferred from the first transport tray 23. After being transferred, it is held on the shelf 38 of the stocker 39 again. Each board holder H in the stocker 39
The substrate B held thereby is heated by the heater 40 and degassed. Next, the first gate valve 8 is opened to communicate the growth chamber 2 and the substrate preparation chamber 10, and the second transfer tray 24, which has received one substrate holder H from the preheating device 37, is opened by the first gate valve 8. Step 8 into the growth chamber 2, and enter the growth chamber 2 as described above.
The substrate is transferred to the substrate support 3 inside. After the transfer, the second transport tray 24 returns to the substrate preparation chamber 10, and the first gate valve 8 is closed. In the growth chamber 2, after degassing for a predetermined time, crystal growth by molecular beam epitaxy is performed on the growth surface of each substrate B held by the substrate holder H in a predetermined manner. Next, an example of a procedure for carrying out the crystal-grown substrate B from the growth chamber 2 will be described. After the substrate preparation chamber 10 is brought into a high vacuum state, the first gate valve 8 is opened. the substrate holder mounting part 13 of the substrate support 3 which is in an upward movement state in the growth chamber 2;
The rotational position of 13 is controlled so that it faces the movement axis direction of the second transport tray 24, and the second transport tray 24 is positioned between the substrate holder placement parts 13, 13.
is expanding. Then, the substrate holder mounting section 13,1
3 moves downward, the substrate holder H is transferred onto the second transport tray 24. Note that at this time, the second gate valve 9 is closed. The second transport tray 24 is retracted into the substrate preparation chamber 10, and the first gate valve 8 is closed.
During this time, the substrate loading chamber 11 is in a vacuum state, and the substrate B on the substrate holder H placed on the second transfer tray 24, which has been placed in the transfer position, advances to the transfer position by opening the second gate valve 9. The paper is transferred to the first transport tray 23 which has been loaded. When the transfer is completed, the first transport tray 23 holding the substrate B is retracted to the substrate receiving position in the substrate loading chamber 11, and the second gate valve 9 is closed. Then, the pressure in the substrate loading chamber 11 is increased, and the crystal-grown substrate B is taken out from the substrate loading hole 29. Further, the substrate holder that has become empty after the substrate B has been transferred to the first transport tray 23 in the substrate preparation room 10 is transported to the preheating device 37 while being placed on the second transport tray 24, and is transported to the stocker 39. is placed on a predetermined shelf 38. However, no matter which transportation procedure is used,
In the present invention, during device operation, the substrate holder H
is moved only between the substrate preparation chamber 10, where a high vacuum is maintained, and the growth chamber 2, where an ultra-high vacuum is maintained, and does not come into contact with the atmosphere at all. Therefore, the problems associated with the conventional concept of transporting the substrate B, in which the substrate is loaded into the substrate holder in the air and transported to the growth chamber via the substrate preparation chamber, are completely eliminated. Note that the procedure for transporting the substrate B is not limited to the above example. It is also possible to carry out the operation of the growth chamber 2 continuously for a long period of time by carrying in and carrying out the substrates B for each substrate holder alternately, making good use of the preheating chamber 37 as a buffer. Note that the first transport tray 23, the second transport tray 24, which are the main components of the substrate transport system, which is the main part of the present invention,
Substrate holder H placed on this, substrate transfer mechanism 2
8. The relationship between the preheating device 37 and the substrate holder placement parts 13, 13, etc. in the growth chamber is schematically shown in FIG. This will make it easier to understand the above-mentioned substrate loading and unloading operations. Of course, the scope of the invention is not limited to the embodiments described above. For example, in the example:
Although a preheating chamber 37 is provided inside the substrate preparation chamber 10, whether or not to provide this is a matter of choice.

[Brief explanation of drawings]

FIG. 1 is a planar sectional view of an embodiment of the present invention;
FIG. 2 shows details of the growth chamber, and is an enlarged sectional view taken along the - line in FIG. 1, FIG. 3 is an enlarged sectional view taken along the - line in FIG. 1, and FIG. 4 is an enlarged plan view of the substrate holder H. , FIG. 5 is an enlarged sectional view taken along the - line in FIG. 4, FIG. 6 is an enlarged plan view of the first conveyance tray, and FIG.
The figure is an enlarged plan view of the second conveyance tray, and FIG.
Fig. 9 is an enlarged sectional view taken along the - line in Fig. 1, Fig. 10 is an enlarged sectional view taken along the - line in Fig. 1, and Fig. 11 is the substrate transfer mechanism. FIG. 12 is a schematic perspective view showing the arrangement of the main components of this embodiment, and FIG. 13 is a schematic diagram showing the growth chamber of a conventional molecular beam epitaxy apparatus. The cross-sectional view, FIG. 14, is a schematic diagram of the entire conventional molecular beam epitaxy apparatus. 2...Growth chamber, 3...Substrate support, 8...First gate valve, 9...Second gate valve, 10...
...Substrate preparation room, 11...Substrate loading room, 23...First transport tray, 24...Second transport tray, 28...
...Substrate transfer mechanism, H...Substrate holder, B...Substrate.

Claims (1)

[Claims] 1. A growth chamber capable of ultra-high vacuum depressurization and having a substrate support for supporting a substrate held in a substrate holder, and a growth chamber that is connected to the growth chamber through a first gate valve. A substrate preparation chamber connected to the substrate preparation chamber and capable of vacuum reduction, and a substrate loading chamber connected to the substrate preparation chamber via a second gate valve, capable of vacuum reduction and having a substrate loading port. The substrate loading chamber is capable of reciprocating movement from a substrate receiving position therein to a substrate transfer position in the substrate preparation chamber through the open second gate valve, and a substrate is placed therein. A first transfer tray for holding the substrate is provided, and a substrate holder for holding the substrate is placed in the substrate preparation chamber, and the substrate is transferred from the substrate transfer position to the growth chamber through the first gate valve in an open state. A second transport tray that can reciprocate up to the substrate support, and a substrate transfer between the first transport tray at the substrate transfer position and the substrate holder on the second transport tray also at the substrate transfer position. The growth chamber is equipped with a substrate transfer mechanism, and the substrate support in the growth chamber is configured to transfer the substrate holder to and from the second transport tray that has been moved into the growth chamber. Molecular beam epitaxy equipment.