JPH10251089A - Apparatus for pulling up cusp magnetic field - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to retreat the drum body of a furnace from the apparatus by directly supporting this body and to facilitate the control of a magnetic field. SOLUTION: The drum body 1a of the furnace 1 for heating a crucible housing a raw material melt and annular cusp magnetic field impressing magnets 3 which are arranged to face each other apart spacings from each other above and below on the circumference of the cylindrical body 1 and are enclosed by magnetic shields 22 on their own upper and lower surfaces and outer flanks are integrally fixed. The apparatus is provided with a drum body retreating means 21 which is fixed to at least either of the drum body or the magnetic shields and retreats the drum body together with the magnets from the crucible, by which the drum body of the furnace is directly supported via this drum body retreating means and the supported drum body is separated from an upper chamber and the upper cap and is retreated from the crucible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cusp magnetic field pulling apparatus for pulling up and growing a single crystal while applying a cusp magnetic field to a raw material melt, and more particularly to a cusp magnetic field effective for improving workability such as maintenance. The present invention relates to a magnetic field pulling device.

[0002]

2. Description of the Related Art Conventionally, the Czochralski method has been widely used as a method for producing a semiconductor single crystal from a raw material melt. Further, in this method, when pulling a single crystal from the conductive raw material melt, a heat convection in the raw material melt is suppressed by applying a magnetic field to the raw material melt from the outside, whereby growth stripes and It is possible to control defects.

Conventional methods for applying a magnetic field include a method for applying a magnetic field in the horizontal or vertical direction and a method for applying an axisymmetric cusp magnetic field. The latter cusp magnetic field application method applies an axisymmetric magnetic field. The application is excellent in that the temperature distribution of the raw material melt can be maintained axially symmetric, whereby a uniform crystal without growth stripes can be obtained.

FIG. 7 shows a cusp magnetic field pulling apparatus for producing a single crystal while applying a cusp magnetic field to a raw material melt. In the figure, reference numeral 1 denotes a furnace, 2 denotes a crucible, 3 denotes a magnet,
4 is an upper chamber, 5 is a revolving arm, 6 is a rod which is raised and lowered by a hydraulic cylinder (not shown), and 7 is a raw material melt. The furnace 1 has a cylindrical body 1a, and an upper lid 1b and a bottom lid 1c for closing the upper and lower parts of the body 1a, respectively.
And the bottom cover 1 are detachably assembled.
It is supported from below by the furnace support 8 via c.

[0005] A crucible 2 for accommodating the raw material melt 7 and a heater (not shown) for heating the stored raw material melt 7 are arranged inside the body 1 a. The crucible 2 penetrates through the bottom cover 1c to keep the horizontal plane where the applied cusp magnetic field becomes zero gauss and the level of the raw material melt 7 which decreases as the single crystal is pulled up. The crucible is supported by a crucible support rod (not shown) which is introduced thereinto so as to be able to move up and down.

The rod 6 is connected to the body 1 via a support arm 9.
It is fixed to a support post 10 disposed on the rear surface of a, and moves up and down by the operation of the hydraulic cylinder. The upper chamber 4 is connected to the body 1a through the upper lid 1b in order to pull up and grow a single crystal from the crucible 2, and is connected to the revolving arm 5
And is fixed to the rod 6 via the. This allows
The upper chamber 4 is supported so as to be rotatable around the axis of the rod 6 and to be able to move up and down in the axial direction, so that it can be retracted from above the body 1a.

The upper lid 1b is also supported like the upper chamber 4 so as to be pivotable about the axis of the rod 6 and to be able to move up and down in the axial direction.
Can be evacuated from above. Magnet 3,3
Are ring-shaped magnets having the same polarity, and are arranged around the body 1a with a vertical interval or opposed to each other with the non-magnetic body 11 interposed therebetween.
The upper and lower end surfaces and the outer side surface are covered by a magnetic shield 12 and supported by a screw jack 14 operated by a drive mechanism 13 from below to be able to move up and down.

The magnetic shield 12 is a hollow annular shield provided so that the magnetic field applied to the raw material melt 7 by the magnets 3 and 3 is not disturbed by the influence of peripheral devices. Is used.
Further, as described above, the magnet 3,
3 have the same polarity and repel each other, so that the magnetic shield 12
3 receive a force in a direction to widen the mutual distance. Therefore, the magnetic shield 12 is configured to have strength enough to withstand not only a shield but also a repulsive force between the magnets 3.

In the cusp magnetic field pulling apparatus having the above-described structure, the body 1a may be withdrawn from the crucible 2 for maintenance or the like. Hereinafter, a procedure for removing the body 1a will be described with reference to FIG. Since the periphery of the body 1a is surrounded by the magnets 3, 3, it is necessary to retract the magnets 3, 3 to expose the body 1a. Therefore, the magnets 3, 3 are retracted to the lower position indicated by the chain line by operating the screw jack 14, thereby exposing the body 1a.

Here, the body 1a is only supported from below through the bottom cover 1c, and the cusp magnetic field lifting device is not provided with any retreating means. It cannot be evacuated from the crucible 2 in the state. Therefore, the body 1a needs to be retracted in a state of being integrated with the upper lid 1b by operating the rod 6 by the hydraulic cylinder while being attached to the upper lid 1b.

Therefore, while the body 1a is still attached to the upper cover 1b, the body 1a and the bottom cover 1c are separated, the rod 6 is operated to raise the upper chamber 4 and the body 1a, and then the swing arm 5 Is turned to retreat to the upper left position indicated by the chain line, and the body 1a is removed.

[0012]

As described above, the conventional cusp magnetic field pulling apparatus does not have a retracting means for directly supporting the body 1a and retracting it from the crucible 2, so that maintenance and the like are performed. In this case, the body 1a is
If they are not integrated and assembled, they cannot be evacuated, and even if they need to be evacuated and taken out separately, the work cannot be performed, resulting in poor workability. In addition, since the control of the magnetic field is performed by adjusting the mutual interval between the magnets 3, there is a problem that it is difficult to perform detailed control.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a structure in which a furnace body and a magnet are integrally fixed, and these can be directly supported and evacuated from a crucible, and magnetic field control is easy. It is an object of the present invention to provide a simple cusp magnetic field pulling device.

[0014]

According to the present invention, there is provided a cusp magnetic field pulling apparatus, comprising: a body of a furnace for heating a crucible containing a raw material melt; A ring-shaped cusp magnetic field applying magnet whose upper and lower surfaces and an outer surface are surrounded by a magnetic shield is integrally fixed. Further, there is provided a body retreat means fixed to at least one of the body and the magnetic shield for retreating the body together with the magnet from the crucible.

In the present invention, the fuselage and the magnet can be supported by the fuselage retracting means in a state where the fuselage and the magnet are integrally fixed, and these can be retracted from the crucible. Therefore, it is possible to eliminate the operation of retracting the magnet from the periphery of the body, which has been performed prior to the operation of retracting the body, and to separately retract and take out the body, the upper chamber, and the upper lid.

Further, since the repulsive force of the magnets received by the magnetic shield can be borne on the side wall of the body, the function as a strength member required for the magnetic shield can be reduced. Further, the magnetic field can be controlled by electrically controlling these magnets while maintaining a constant interval between the magnets, so that the magnetic field can be easily controlled.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
An example of an embodiment of the present invention will be described. In the figure, reference numeral 21 denotes a body retreating means, 22 denotes a magnetic shield, and 23 denotes a revolving arm. The same components as those in FIG. The side wall of the body 1a is composed of an inner cylindrical portion 24 and an outer cylindrical portion 25 made of stainless steel, and between the inner cylindrical portion 24 and the outer cylindrical portion 25,
A gap (hereinafter referred to as a water cooling jacket 26) is formed, and the water cooling jacket 26 is filled with cooling water.

This cooling water is circulated in the water cooling jacket 26, thereby reducing the influence of furnace heat on other components arranged around the body 1a. The outer cylindrical portion 25 has a thread groove 27 for fixing the magnetic shield 22 to the body 1a.
The magnetic shield 22 is a hollow annular shield provided so that the magnetic field applied to the raw material melt 7 by the magnets 3 and 3 is not disturbed by the influence of peripheral devices. Used.

As shown in FIG. 6, flanges 2 for fixing to the body 1a are provided on upper and lower end surfaces of the magnetic shield 22.
8, and a screw insertion hole 29 is formed in the flange 28. Then, the magnets 3 are fixed to and separated from the body 1a so that the magnets 3 and 3 can be separated from each other.
2 and the body 1 through the flange 28
a is screwed to the outer cylindrical portion 25 by a bolt 30;
It is fixed to the body 1a.

Here, the magnets 3, 3 have the same polarity and repel each other, and the magnetic shield 22 receives a repulsive force F between the magnets 3, 3 as shown in FIG. However, by fixing the magnetic shield 22 to the side wall of the body 1a, that is, the outer cylindrical portion 25, the repulsive force F can be borne by the body 1a. Can be used to form the magnetic shield 22.

As shown in FIGS. 2 to 5, the body retreating means 21 is fixed to the hydraulic cylinder 31 and the rod 31a constituting the elevating means, and is rotatably fixed to the rod 31a, and is engageable with the body 1a. A pair of upper and lower turning arms 23
It is composed of The rod 31a is connected to the rod 6
Similarly to the above, it is fixed to a column 10 disposed on the rear surface of the body 1 a via a support arm 32, and is moved up and down by the operation of a hydraulic cylinder 31.

A pair of revolving arms 23 are provided on the arm fixing portion 33 of the rod 31a so as to be vertically separated from each other.
As shown in FIG. 1, the distal ends of both swing arms 23 are screwed to the magnetic shield 22 by bolts 34.

Next, a description will be given of a procedure for retracting the body 1a from the crucible 2 and taking out the same in order to perform maintenance or the like of the cusp magnetic field pulling apparatus having the above-described configuration. First, FIG.
As shown in (2), the body 1a is separated from the upper lid 1b, and the rod 31a is operated to retract the upper chamber 4 and the upper lid 1b to the upper left position indicated by the chain line. Next, the body 1a is separated from the lower lid 1c, and the rod 31a is operated to move the body 1a.
a, and further pivot the arm 23 to the rod 31
It is rotated about the axis of a and retracted to the upper right position indicated by the chain line.

Thus, the body 1a and the magnets 3, 3
Are integrally fixed, and these are simultaneously
The magnets 3, 3 are retracted to a lower position prior to the retreat work of the body 1a,
The operation of exposing the body 1a can be eliminated. The body 1a is directly supported by the rod 31a via the furnace evacuation means 21 and retracted, so that the body 1a
And the upper chamber 4 and the upper lid 1b can be separately retracted.

Further, by fixing the magnets 3, 3 in close contact with the side wall (outer cylindrical portion 25) of the body 1a, the distance between the magnets 3, 3 and the body 1a can be shortened, thereby separating the magnets 3, 3 from the periphery of the body 1a. The magnetic field applied to the raw material melt 7 can be strengthened as compared with the case where the raw material melt 7 is disposed.

As a result, the size of the magnets 3 and 3 can be reduced,
Power consumption can be reduced, and operability and cost can be reduced during maintenance work and the like. Further, since the magnetic field can be controlled by electrically controlling these magnets while maintaining a constant interval between the magnets 3, the magnetic field can be easily controlled, and the workability can be improved. Can be further improved.

In the cusp magnetic field pulling apparatus according to the present invention, the turning arm 23 is shown as being engaged with the magnets 3, 3, but the body 1a or these bodies 1a are not shown.
The embodiment may be such that it engages with both the magnets 3 and 3.

[0028]

According to the cusp magnetic field pulling device of the present invention,
The fuselage and the magnet can be supported in a state of being fixed integrally by the fuselage retracting means, and these can be retracted from the crucible. Therefore, the magnet is retracted from around the fuselage, which was conventionally performed prior to the retraction of the fuselage. Work can be eliminated, and the body, the upper chamber, and the upper lid can be separately retracted and taken out, thereby improving the workability of maintenance and the like.

Further, since the repulsive force of the magnets received by the magnetic shield can be borne on the side wall of the body, the function as a strength member required for the magnetic shield can be reduced. This has the effect of reducing restrictions on dimensions and the like, and reducing costs. Furthermore, since the magnetic field can be controlled by electrically controlling these magnets while maintaining a constant interval between the magnets, the magnetic field can be easily controlled, and the workability is further improved. Can be achieved.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing an example of an embodiment of a cusp magnetic field lifting device according to the present invention.

FIG. 2 is a front view including a cross section of a part of the cusp magnetic field lifting device.

FIG. 3 is a plan view of FIG. 2;

FIG. 4 is a right side view of FIG. 2;

FIG. 5 is a left side view of FIG. 2;

FIG. 6 is a perspective view of a magnetic shield of the cusp magnetic field pulling device.

FIG. 7 is a front view partially including a cross section showing a state in which the furnace body of the conventional cusp magnetic field pulling device is retracted from the crucible.

[Explanation of symbols]

 Reference Signs List 1 furnace 1a body 2 crucible 3 magnet 7 raw material melt 21 body retreat means 22 magnetic shield

Claims (2)

[Claims] 1. A furnace body for heating a crucible containing a raw material melt, and a furnace body is disposed so as to be opposed to each other around the body at an interval above and below, and its upper and lower surfaces and an outer surface are surrounded by a magnetic shield. And a ring-shaped cusp magnetic field applying magnet fixed integrally. 2. A cusp magnetic field attraction device according to claim 1, further comprising: a body retreat means fixed to at least one of said body and said magnetic shield to retreat said body together with said magnet from said crucible. Upper device.