JPH08188493A - Equipment for producing single crystal - Google Patents

Abstract

PURPOSE: To contrive miniaturization of the subject producing equipment and congraction of its setting area by placing plural signal crystal-growing troughs in a row at a prescribed interval and placing electromagnetic coils giving a magnetic field to molten semiconductor at a central part of the single crystal- growing groughs and between end part of the row and each trough. CONSTITUTION: Plural single crystal-growing troughs 10 each dipping a seed crystal in molten semiconductor in a crucible in a state filled with an inert gas, pulling up the seed crystal according to the crystal growth to grow the single crystal semiconductor are placed in a row at a prescribed interval. Electromagnetic coils 11a at both ends and electromagnetic coils 11 between the single crystal-growing troughs are placed along with the single crystal-growing troughs 10 and fitting to the height of the molten semiconductor in the center part. A magentic body 12 forming a return circuit detouring outside of the single crystal-growing troughs 10 is placed between both the two end part electromagnetic coils 11a placed on both ends. The arrangement of the single crystal- growing troughs 10 is a two-row arrangement or a round one.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single crystal manufacturing apparatus for manufacturing a single crystal semiconductor by applying a magnetic field to a molten semiconductor in a crucible to pull up a seed crystal.

[0002]

2. Description of the Related Art A single crystal semiconductor used for a semiconductor device or the like is required to be highly pure and homogeneous. The single crystal semiconductor is manufactured by putting a semiconductor such as silicon, which is highly purified, into a crucible and melting it, and immersing a seed crystal in a molten semiconductor solution and rotating it to pull it up according to the growth of the single crystal. In the process of manufacturing a single crystal, the molten semiconductor in the crucible is overheated by a heater arranged around and kept at a predetermined temperature, but the molten semiconductor causes thermal convection between the center and the inner wall of the crucible. The molten semiconductor and the quartz crucible react with each other, and oxygen, which is the main component of quartz, and impurities in the quartz glass are taken into the semiconductor solution. If the oxygen and impurities are mixed in the single crystal, an impurity layer containing oxygen may be locally formed. As a method of avoiding such a phenomenon, a manufacturing method is adopted in which a strong magnetic field is applied to the crucible portion in which the molten semiconductor is stored to prevent convection.

For example, a single crystal semiconductor used for a semiconductor element or the like is manufactured by an apparatus as shown in FIGS. FIG. 10 is a sectional view of a conventional single crystal manufacturing apparatus, and FIG.
FIG. 11 is a perspective view of the entire configuration of FIG. 10. In FIG. 10 and FIG. 11, 10 is a single crystal growth tank, and a crucible 1 for storing the molten semiconductor 2, a heater 3 for overheating the molten semiconductor 2,
A pulling mechanism 6 equipped with a pulling chuck 5 that is equipped with a single crystal seed 4 at the tip and pulls up according to crystal growth, and a crucible 1 are housed, and an inert gas is sealed inside, and an upper container 7a and a lower container 7b are provided. The container is dividable, and the upper container 7a is provided with an inert gas inlet 7c, the lower container 7b is provided with a discharge port 7d, and a crucible rotating mechanism 8 for rotating the crucible 1. Reference numeral 9 denotes a support column that supports the lifting mechanism 6, and the lifting mechanism 6 and the upper container 7a are supported by the support arm 9a. Reference numeral 11 is an electromagnetic coil that applies a magnetic field to the molten semiconductor 2 in the crucible 1, 12 is a magnetic body that forms a return path of the magnetic field, and 16 is a pedestal.

Next, the operation will be described. In the single crystal manufacturing apparatus having the above-described structure, a purified semiconductor material such as highly purified silicon is put into the crucible 1 and heated by the heater 3 to melt it. It is maintained at a predetermined temperature.
The single crystal semiconductor 4 is manufactured by immersing the single crystal seed 4 supported by the pull-up chuck 5 in the liquid surface of the molten semiconductor 2 and pulling it up as the crystal grows while rotating. A magnetic field is applied to the molten semiconductor 2 in the crucible 1 by a pair of electromagnetic coils 11 provided on the outer circumference of the container. Since the molten semiconductor 2 is conductive, even if there is a slight temperature difference between the central portion and the outer peripheral portion, convection is suppressed by applying a strong magnetic field.

When convection does not occur in the molten semiconductor 2, the oxygen concentration inside the molten semiconductor 2 becomes low, the growth of the single crystal becomes stable, and a single crystal semiconductor of high purity can be obtained.

The electromagnetic coil 11 for applying a magnetic field to the molten semiconductor 2 has a normal conducting system and a superconducting system. The normal conducting system is a structure in which the electromagnetic coils 11 are arranged on both sides of the container and a direct current is passed through, and a power supply device for supplying a direct current and a cooling means for increasing the temperature of the coil are required. In the normal conduction system, when a large current is applied, the current value that can be applied is limited due to the balance between the temperature rise and the cooling means, and a very strong magnetic field cannot be applied. In the case of the superconducting method, once a current flows through the coil, it will flow permanently, so it is sufficient if there is a power source that excites first as a power supply device, and since there is no temperature rise, no cooling means is required and a strong magnetic field is easily manufactured. It is possible to give a strong and stable magnetic field.

The conventional single crystal manufacturing apparatus has the
This is a configuration in which electromagnetic coils are arranged on both sides of the base container. To increase the manufacturing capacity, it is necessary to increase the number of the above-mentioned configurations. In the single crystal pulling apparatus configured by one container, the electromagnetic coils 11 are arranged on both sides of one container, and therefore, including the incidental equipment, a considerably wide installation place is required.

[0008]

In order to increase the production amount of single crystal semiconductors, the number of single crystal pulling apparatuses must be increased, but the installation area must be wide and the equipment cost is high. was there.

The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide a single crystal manufacturing apparatus in which the number of electromagnetic coils that apply a magnetic field to a plurality of crucibles is reduced and the installation area is reduced. To aim.

[0010]

According to a first aspect of the present invention, a plurality of single crystal growth tanks are arranged in a row at a predetermined interval, and the end of the row and each single crystal growth tank are arranged. An electromagnetic coil for applying a magnetic field to the molten semiconductor at the center of the single crystal growth tank is arranged between the two.

According to a second aspect of the present invention, a magnetic field return path is formed between the end electromagnetic coils at the left and right ends of the first aspect.

According to a third aspect of the present invention, a plurality of single crystal growth tanks are arranged in a row at a predetermined interval and are arranged in two rows in the front and rear, and end electromagnetic fields at both left and right ends of the front and rear rows are arranged. A magnetic field return path is formed between the front and rear rows of coils.

In the invention according to claim 4 of the present invention, a plurality of single crystal growth tanks are arranged in a circle, and the molten semiconductor in the central portion of each single crystal growth tank is provided between each single crystal growth tank. An electromagnetic coil that gives a magnetic field is arranged.

According to a fifth aspect of the present invention, an iron core is attached to the inner diameter portion of the electromagnetic coil arranged between the single-crystal growth tanks arranged in a circle of the single-crystal manufacturing apparatus of the fourth aspect. The end faces of the iron core are arranged so as to face each other in parallel with the single crystal growth tank as the center.

According to a sixth aspect of the present invention, the electromagnetic coil of the single crystal manufacturing apparatus according to any one of the first to fifth aspects is a superconducting electromagnet coil.

According to a seventh aspect of the present invention, a cryogenic cooling medium can flow between the plurality of superconducting electro-magnetic coil containers of the single crystal manufacturing apparatus according to the sixth aspect. .

[0017]

According to the first aspect of the present invention, a plurality of single crystal growth tanks are arranged in a row at a predetermined interval, and the single crystal growth tank is provided between the end of the row and each single crystal growth tank. Since the electromagnetic coil for applying a magnetic field to the molten semiconductor is arranged, the installation area corresponding to one single crystal growth tank can be reduced.

According to claim 2 of the present invention, claim 1
Since the magnetic field return path is provided between the end electromagnetic coils at the left and right ends of the magnetic field, the external leakage magnetic field is reduced.

In a third aspect of the present invention, a plurality of single crystal growth tanks are arranged in a row at a predetermined interval, and an electromagnetic coil is arranged between the end of the row and each single crystal growth tank. By arranging the structure in two rows, the single crystal growth tank 1
The installation area corresponding to the base can be reduced. Further, since the magnetic field return path is provided between the front and rear rows of the end electromagnetic coils at the left and right ends, the external leakage magnetic field is reduced by the short magnetic field return path.

According to the fourth aspect of the present invention, the plurality of single crystal growth tanks are arranged in a circle at a predetermined interval, and the electromagnetic coil is arranged between the single crystal growth tanks. The number of single crystal growth tanks is the same as the number of single crystal growth tanks, and the installation space per device can be significantly reduced, and external leakage magnetic fields can be almost eliminated without providing a magnetic field return path.

According to claim 5 of the present invention, claim 4
The iron core is attached to the inner diameter part of the electromagnetic coil arranged between the single crystal growth tanks arranged in a circle in the single crystal manufacturing apparatus of, and the end faces of the iron core are arranged so as to face each other in parallel with the single crystal growth tank as the center. Therefore, the magnetic field inside the single crystal growth tank can be made uniform, and the external magnetic field can be almost eliminated.

According to claim 6 of the present invention, claim 1
Since the electromagnetic coil of the single crystal manufacturing apparatus according to any one of claims 5 to 6 is a superconducting electro-magnetic coil, a constant and stable magnetic field can be obtained after once excited, and an excitation power source is unnecessary.

According to claim 7 of the present invention, claim 6
Since the cryogenic cooling medium can be circulated between the plurality of superconducting electro-magnetic coil containers of the single crystal manufacturing apparatus described in (1), the number of service ports for filling the cooling medium and inserting the power supply lead for initial excitation can be set. Can be reduced.

[0024]

Embodiments of the present invention will be described below. Example 1. FIG. 1 is a configuration diagram of an embodiment in which two single crystal growth tanks of a single crystal manufacturing apparatus according to the present invention are integrally configured. In the figure, 10 is a single crystal growth tank, and FIG.
As in the conventional example of No. 0, the crucible 1 in which the molten semiconductor 2 is put is placed in the container, the heater 3 for overheating the crucible 1, the rotating mechanism 8 for rotating the crucible 1, and the pulling mechanism 6 for pulling up the single crystal.
It is provided with. Reference numeral 11 denotes an electromagnetic coil arranged between a plurality of single crystal growth tanks 10, 11a denotes an end electromagnetic coil arranged at an end of the single crystal growth tanks 10 arranged in a row, And is arranged according to the height of the molten semiconductor at the center. Reference numeral 12 is a magnetic body that forms a magnetic field return path by bypassing the outside of the single crystal growth tank 10 between the end electromagnetic coils 11a arranged at the left and right ends.

With this structure, the single crystal growth tank 10
However, the number of electromagnetic coils 11 and 11a may be three with respect to two,
Compared with the case where the single crystal growth tank 10 is composed of two units, the number of the electromagnetic coils 11 is reduced by one to three, and the magnetic body 12 constituting the magnetic field return path has a longer magnetic path length. The number of magnetic materials is smaller than that in the case of two units having a single structure, and there is an advantage that the installation area per unit is small.

FIG. 2 is a block diagram of a single crystal manufacturing apparatus in the case where three single crystal growth tanks 10 are integrally formed. In this case, three single crystal growth tanks 10 are integrally formed. With this configuration, the number of the electromagnetic coils 11 between the single crystal growth tanks 10 is two and the number of the electromagnetic coils 11a at the end is two, which is two less than that of the single configuration. The magnetic body 12a forming the magnetic field return path is only lengthened by one unit of the single crystal growth tank 10. When a plurality of single crystal growth tanks 10 are integrally configured, the number of electromagnetic coils 11 and 11a can be (the number of single crystal growth tanks x 2-1), and when a large number of single crystal manufacturing apparatuses are required. In addition, the installation area can be made small and the equipment cost can be kept low.

Example 2. In FIG. 3, two single crystal growth tanks 10 are arranged in a row, and an electromagnetic coil 11 is provided between the single crystal growth tanks 10.
And the end electromagnetic coils 11a are arranged at the ends, and this configuration is arranged in two rows in the front and rear. In this configuration, the number of electromagnetic coils 11 is one for one row, and the number of devices is two less than that of the apparatus in which four single crystal growth tanks 10 are solely configured. Since the magnetic field return path can be arranged between the front and rear end electromagnetic coils 11a at the left and right ends, the weight of the magnetic body 13 can be reduced, and the installation area corresponding to one unit can be compared with the case of the first embodiment. Is smaller and the equipment cost can be kept lower.

In FIG. 4, 103 single crystal growth tanks are arranged in a row, and an electromagnetic coil 11 and an end electromagnetic coil 11a at the end of the row are arranged between each single crystal growth tank 10. It was placed in. In this case, the installation area corresponding to one unit is further smaller than that of the structure of two units and two rows in FIG. 3, and the equipment cost can be further reduced.

Example 3. In FIG. 5, six single crystal growth tanks 10 are arranged in a circle, and an electromagnetic coil 11 is arranged between the single crystal growth tanks 10. With this configuration,
The number of single crystal growth tanks 10 and the number of electromagnetic coils 11 may be the same, and the number of electromagnetic coils 11 can be further reduced as compared with the case of the first and second embodiments.

When a plurality of single crystal growth tanks are arranged in a circle, the magnetic field inside each single crystal growth tank 10 becomes an arcuate curved magnetic field, but the convection prevention function of the molten silicon inside the single crystal growth tank 10 is sufficient. Can be obtained.

By thus arranging the single crystal growth tanks in a circular shape, the support columns 9 for supporting the pulling mechanism 6 of the single crystal growth tanks can be provided commonly to six groups. Further, if the outer peripheral portion, which is a work place, is a rotary type, the single crystal can be easily taken out easily.

Example 4. FIG. 6 shows the case where the single crystal growth tanks 10 of Example 3 are arranged in a circle, and each single crystal growth tank 1
This is an improvement in that the internal magnetic field of 0 becomes a curved magnetic field having an arc shape. The end shape of the electromagnetic coil 11 between the single crystal growth tanks 10 is changed to that of the single crystal growth tank 10. An iron core 15 having a shape in which the internal magnetic fields are parallel to each other is inserted. By inserting the iron core 15, the single crystal growth tank 1 is arranged in a circular shape even though the single crystal growth tank 10 is arranged in a circular shape.
The internal magnetic field of 0 can be converted into a parallel magnetic field.

Example 5. Although the above Examples 1 to 4 have been described without specifying the structure of the electromagnetic coil, in Example 5, the electromagnetic coil of Examples 1 to 4 is wound with a superconductor, and the sealed container is filled with a cryogenic cooling medium. It is a superconducting electro-magnetic coil that is housed as a housing. When the superconducting electromagnet coil is used in this manner, a constant magnetic field can be permanently given only by exciting at the beginning of operation, so that a stable single crystal semiconductor can be efficiently manufactured.

Embodiment 6 FIG. The sixth embodiment is configured such that the cryogenic cooling medium can flow between the containers of the plurality of superconducting magnetic coils. The structure is shown in FIG. In FIG.
Reference numeral 20 is a superconducting magnetic coil around which a superconducting wire is wound, 21 is a cryogenic container containing the superconducting magnetic coil 20 and filled with a cryogenic cooling medium 22, and 23 is a lead for supplying an exciting current to the superconducting magnetic coil 20. And a service port for replenishing the cryogenic cooling medium, 24 is a vacuum container accommodating the cryogenic container and kept in vacuum, and 25 is the cryogenic container 2
1 and the vacuum container 24, which is a heat shield for thermally shielding the cryogenic container 21 and the vacuum container 24. The two superconducting electro-magnetic coil containers are connected from the inside by upper and lower routes by a connecting connecting pipe 26 in which a cryogenic connecting pipe 20a, a heat shield connecting pipe 25a, and a vacuum connecting pipe 24a are multilayered. FIG. 8 shows the case of the two-unit two-row arrangement of the second embodiment, and FIG.
2 shows a configuration in which the superconducting electromagnet coils in the front and rear rows are connected by the communication connecting pipe 26 in the case of three groups and two rows.

If two superconducting electro-magnetic coils arranged close to each other are constructed in this way, the service port 23 is provided on only one side, so that the structure becomes simple and handling becomes easy. Depending on the installation conditions of the device, a larger number of superconducting electro-magnetic coils may be connected to each other, and the device becomes easier to handle.

[0036]

In the invention according to claim 1 of the present invention, a plurality of single crystal growth tanks are arranged in a row, and the electromagnetic coil is arranged between the end of the row and each single crystal growth tank. This has the effect of reducing the installation area equivalent to one single crystal growth tank.

The invention according to claim 2 of the present invention has the effect of reducing the external leakage magnetic field because the magnetic field return path is formed between the end electromagnetic coils at the left and right ends of claim 1.

In the invention according to claim 3 of the present invention, a plurality of single crystal growth tanks are arranged in a row at a predetermined interval and are arranged in two rows in the front and rear, and end electromagnetic fields at both left and right ends of the front and rear rows are arranged. Since the magnetic field return path is formed between the front and rear rows of the coils, the installation area corresponding to one single crystal growth tank can be reduced, and the short magnetic field return path has the effect of reducing the external leakage magnetic field.

In the invention according to claim 4 of the present invention, a plurality of single crystal growth tanks are arranged in a circle, and the molten semiconductor in the central portion of each single crystal growth tank is provided between each single crystal growth tank. The number of electromagnetic coils is the same as that of the single crystal growth tank because the electromagnetic coils that provide a magnetic field are arranged in the device, and the installation space per unit can be significantly reduced, and the external leakage magnetic field can be almost eliminated without providing a magnetic field return path. There is an effect that can be.

In the invention according to claim 5 of the present invention, an iron core is attached to the inner diameter portion of the electromagnetic coil between the single crystal growth tanks arranged in a circle, and the end faces of the iron core are parallel to the single crystal growth tank. The magnetic field inside the single crystal growth tank can be made uniform and the external magnetic field can be almost eliminated.

In the invention according to claim 6 of the present invention, since the electromagnetic coil of the single crystal manufacturing apparatus is a superconducting electro-magnetic coil, a constant and stable magnetic field can be obtained after once excited, and an exciting power source as an apparatus is provided. The effect that it becomes unnecessary and a compact device is obtained.

In the invention according to claim 7 of the present invention, since the cryogenic cooling medium can flow between the containers of the plurality of superconducting magnetic coils of the single crystal manufacturing apparatus, the cooling medium is filled and the initial excitation is performed. It is possible to reduce the number of service ports through which the power supply leads for use are reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment in which two single crystal growth tanks of a single crystal manufacturing apparatus according to the present invention are integrated.

FIG. 2 is a configuration diagram of an embodiment in which three single crystal growth tanks of the single crystal manufacturing apparatus according to the present invention are integrated.

FIG. 3 is a configuration diagram of an embodiment in which two single crystal growth tanks of the single crystal manufacturing apparatus according to the present invention are integrated into two rows.

FIG. 4 is a configuration diagram of an embodiment in which three single crystal growth tanks of the single crystal manufacturing apparatus according to the present invention are integrated into two rows.

FIG. 5 is a configuration diagram of an embodiment in which six single crystal growth tanks of the single crystal manufacturing apparatus according to the present invention are circularly arranged and integrated.

FIG. 6 is a configuration diagram of an embodiment in which six single crystal growth tanks of a single crystal manufacturing apparatus according to the present invention are arranged in a circle and an iron core is inserted into a coil to improve the uniformity of a magnetic field.

FIG. 7 is a configuration diagram showing a configuration in which two superconducting electromagnet coils are connected in the single crystal manufacturing apparatus according to the present invention.

FIG. 8 is a configuration diagram in the case where the electromagnetic coils having the configuration of FIG. 3 are superconducting electromagnet coils and are connected in pairs.

FIG. 9 is a configuration diagram in the case where the electromagnetic coils having the configuration of FIG. 4 are superconducting electromagnet coils and are connected every two coils.

FIG. 10 is a cross-sectional view showing a configuration of a conventional single crystal manufacturing apparatus.

FIG. 11 is a perspective view showing a configuration of a conventional single crystal manufacturing apparatus.

[Explanation of symbols]

10 Single Crystal Growth Tank 11 Electromagnetic Coil 12 Magnetic Material 13 Magnetic Material 20 Superconducting Coil 21 Cryogenic Cylinder 22 Cryogenic Cooling Medium 23 Service Port 24 Vacuum Vessel 25 Heat Shield 26 Communication Connection Pipe

Claims (7)

[Claims] 1. A plurality of single crystal growth tanks for immersing a seed crystal in a molten semiconductor in a crucible in a state filled with an inert gas and pulling it up as the crystal grows to grow a single crystal semiconductor at predetermined intervals. Arranged in a single row, and between each end of the row and each single crystal growth tank, a single crystal characterized by placing an electromagnetic coil for applying a magnetic field to the molten semiconductor in each single crystal growth tank Manufacturing equipment. 2. The single crystal according to claim 1, wherein a magnetic body that forms a magnetic field return path that bypasses the outside of the single crystal growth tank is provided between the electromagnetic coils arranged at both ends. Manufacturing equipment. 3. A plurality of single crystal growth tanks for immersing a seed crystal in a molten semiconductor in a crucible and pulling it up as the crystal grows to grow a single crystal semiconductor at a predetermined interval while being filled with an inert gas. And the electromagnetic coils for applying a magnetic field to the molten semiconductor in each single crystal growth tank are arranged in front and rear two rows between both ends of the row and each single crystal growth tank. The single crystal manufacturing apparatus is characterized in that a magnetic body that forms a magnetic field return path is provided between the front and rear rows of the electromagnetic coils arranged at the ends on each of the left and right sides. 4. A plurality of single crystal growth tanks in which a seed crystal is immersed in a molten semiconductor in a crucible in a state of being filled with an inert gas and pulled up as the crystal grows to grow a single crystal semiconductor are arranged in a circle. A single crystal manufacturing apparatus is characterized in that an electromagnetic coil for applying a magnetic field to the molten semiconductor in each single crystal growth tank is arranged between each single crystal growth tank. 5. An iron core is attached to an inner diameter portion of each electromagnetic coil arranged between the single crystal growth tanks, and end faces of the iron cores facing each other are parallel to each other with the single crystal growth tank as a center. The single crystal manufacturing apparatus according to claim 4, wherein 6. The single crystal production apparatus according to claim 1, wherein the electromagnetic coil is a superconducting electromagnet coil. 7. The single crystal production apparatus according to claim 6, wherein a cryogenic cooling medium is circulated between the containers of the plurality of superconducting magnetic coils.