JPH0316267Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention applies a magnetic field with a uniform magnetic flux density in a direction perpendicular to the crystal pulling direction to a crystal pulling furnace that pulls silicon single crystals, etc. This invention relates to an electromagnetic device that can add

[Conventional technology]

In recent years, in order to obtain single crystals such as silicon that are needed when manufacturing semiconductor products such as transistors and ICs, a horizontal magnetic field is applied to the single crystals at the stage of pulling them from a crystal pulling furnace. Techniques have been developed to apply this.

By applying such a horizontal magnetic field, Lorentz force acts on the conductive material (for example, silicon melt), suppressing the movement of the conductive material, reducing thermal convection, and obtaining high-quality crystals. It is based on the principle of
reference).

Here, an outline of a conventional example of an electromagnet device for applying a horizontal magnetic field to a crystal pulling furnace as described above will be explained with reference to FIGS. 6 and 7.

The electromagnetic device 50 shown in FIG _. 6 and _FIG . It includes a pair of magnetic pole parts 51A and 51B that apply magnetic flux in the X direction (as shown in FIG. 7), and a yoke part 52 that is connected to both magnetic pole parts 51A and 51B and forms a rectangular closed magnetic path.

Both magnetic pole parts 51A, 51B are composed of magnetic cores 53A, 53B that are arranged in parallel with each other at a predetermined interval, with the crystal pulling furnace R having a substantially circular horizontal cross section in between, and these two magnetic cores 53A, 53B.
Coil portions 54A, 54 arranged to be wound around
By passing a current in a fixed direction through each coil portion, the above-mentioned parallel magnetic flux in the X direction is generated and a horizontal magnetic field is applied to the crystal pulling furnace R. In addition, in Figures 6 and 7,
Reference numerals 55A and 55B are recesses for transmitting and receiving magnetic flux provided in the end faces of the coil portions parallel to each other.

The yoke portion 52 has both magnetic pole portions 51A and 51B.
A pair of parallel yokes 56A, 56B arranged parallel to each other on the back side of the
Connecting yokes 57A and 5 that connect 56B respectively
7B, both of which are made of magnetic material and arranged so as to form a rectangular cylindrical closed magnetic path as a whole.

However, this electromagnet device 50 includes the following problems.

First, the magnetic flux in the X direction with respect to the crystal pulling furnace R is not converged because the magnetic flux sending and receiving surfaces of both magnetic pole parts 51A and 51B are arranged in parallel with this crystal pulling furnace R in between.
The magnetic flux near the ends of A and 53B becomes leakage magnetic flux,
The magnetic flux density applied to the crystal pulling furnace R decreases,
Moreover, it becomes non-uniform.

Next, since the yoke portion 52 is arranged so as to form a rectangular cylindrical closed magnetic path as a whole, a useless empty space 5858 is formed outside the magnetic pole portions 51A and 51B as shown in FIG. As a result, this electromagnet device 50 becomes larger and its overall weight also increases. In this case, miniaturization,
If the shape of the yoke part 52 is made smaller or its thickness is made smaller in order to reduce the weight, the magnetic flux density applied to the crystal pulling furnace R becomes lower than that required to obtain a high-quality crystal. The value will be lower than the actual value.

[Problem that the invention attempts to solve]

The purpose of this invention is to provide a small and lightweight electromagnetic device that can ignite a uniform magnetic field on an object to which a magnetic field can be applied.

Still another purpose of this invention is that, for example, the magnetic flux density of the horizontal magnetic field applied to a silicone crystal pulling furnace can be increased compared to conventional ones, and
It is an object of the present invention to provide an electromagnet device suitable for a crystal pulling furnace that can be configured to be compact and lightweight as a whole.

[Means for solving problems]

The outline of this invention to achieve the above purpose is as follows:
Protrudingly opposing magnetic pole parts are formed on the inner circumferential surface of the cylindrical yoke part, and a coil part is arranged on the circumferential side of each of the magnetic pole parts, and the opposing faces of the magnetic pole part and the opposing faces of the coil part are arranged in a protruding manner. , an electromagnet device characterized in that it is formed into a curved surface along the outer peripheral surface of an object to which a magnetic field is applied.

The shape of the yoke portion is not particularly limited as long as it is cylindrical. What kind of cylinder shape to use?
The magnetic field generated by this electromagnetic device may be appropriately determined depending on the shape of the object to be applied to. For example, a circular cylinder shape, an elliptical cylinder shape, or a cylinder shape similar to these may be adopted as appropriate. I can do it. For example, a silicone crystal pulling furnace usually has a circular horizontal cross section, and the silicone crystal pulling furnace is placed between a pair of coil parts of an electromagnetic device.
Preferably, the yoke portion also has a cylindrical shape with a circular horizontal cross section.

The coil section is not particularly limited as long as it can be energized. However, if this electromagnet device is to be used in a silicone crystal pulling furnace, it is necessary to pass a large current through the coil section, and when a large current is passed, the amount of heat generated within the coil section increases. It is preferable that this is constructed from a wound pipe, and the cooling water is allowed to flow through the pipe. It is preferable that the pipe has a rectangular cross section perpendicular to its longitudinal direction, since this allows the pipe to be wound tightly.

Further, in order to improve the magnetic flux density, the coil portion is configured to be wound around a magnetic pole portion that protrudes opposite to the inner circumferential surface of the yoke portion.

The opposed surfaces of the coil portion and the magnetic pole portion are formed into curved surfaces corresponding to the circumferential surface of an object to which a magnetic field is applied, such as a silicone crystal pulling furnace.

In addition, if the opposing surfaces of the pair of opposing magnetic pole parts are formed to be concave in the vertical direction, the magnetic flux can be focused in the vertical direction.
It's even more convenient.

[Effect]

The operation of the apparatus having the above configuration will be explained below.

A current is passed through the pair of coil parts by a current supply means.
Then, the magnetic field generated based on the current flowing through the coil section, for example, the object placed between the pair of coils, is ignited.

In this case, since the facing surfaces of the coil parts are curved surfaces that follow the outer peripheral surface of the object, convergent magnetic flux having a high magnetic flux density in the horizontal direction is transmitted from one coil part to the other coil part. Sent. This converging magnetic flux returns to one of the magnetic poles through a yoke portion having a predetermined shape arranged around each magnetic pole portion.

〔Example〕

An embodiment of this invention will be described below with reference to FIGS. 1 to 5.

The electromagnet device shown in FIGS. 1 and 2 is an electromagnet device 1 for a crystal pulling furnace. This electromagnet device 1 includes magnetic pole parts 3A and 3B, a yoke part 4, and a coil part 8.

The yoke portion 4 is composed of a pair of semi-cylindrical yokes 4A and 4B that are semi-cylindrical and are in close contact with each other to form a cylindrical magnetic path as a whole.

Each of the semi-cylindrical yokes 4A, 4B has magnetic properties so as to form a furnace housing space 2 with a circular horizontal cross section sufficient to accommodate a cylindrical crystal pulling furnace with a circular horizontal cross section in the center. A pair of magnetic pole parts 3A and 3B made of a body are respectively arranged to face each other and protrude from the inner peripheral surfaces of the semi-cylindrical yokes 4A and 4B.

In this case, the opposing surfaces of the magnetic pole parts 4A and 4B form a curved surface along the outer peripheral surface of the crystal pulling furnace, and this curved surface becomes a magnetic flux transmission/reception surface.

Further, the yoke part 4 includes a cooling medium supply part 6 as a part of means for supplying a cooling medium (for example, cooling water), as will be described in detail later, and the magnetic pole part 3A,
3B.

As shown in FIGS. 1 and 4, the coil section 8 is constructed by using an arbitrary number of conductor pipes 7 having a rectangular cross section so that the overall shape thereof becomes a curved circular donut shape. The conductor pipe 7 is wound and overlapped around the magnetic pole part 9 so that the opposing surfaces of the part 3B are curved surfaces having a curvature along a crystal pulling furnace whose horizontal cross section has a circular outer periphery,
The conductor pipe 7 is molded around it with insulating resin.

The coil portion 8 is constructed by winding a single conductor pipe 7 having a rectangular cross section around the outer periphery of the magnetic pole portions 3A and 3B to form a coil, and allows cooling water to flow from one end of the conductor pipe 7 to the other end. However, when this electromagnet device is used as an electromagnet device for a silicone crystal pulling furnace, the amount of heat generated in the coil portion when energized is large, so in the above structure,
Cooling efficiency may be poor.

Therefore, in the case of the electromagnet device for a silicone crystal pulling furnace, the coil section 8 is constructed by first winding a first conductor pipe having a rectangular cross section and sealed at both ends around the outer periphery of the magnetic pole section. The surface is molded with resin and insulated. Next, a second conductor pipe similar to the first conductor pipe is wound around the first conductor pipe, and an insulation treatment is applied to the outer surface of the second conductor pipe.
Thereafter, a desired number of conductor pipe layers are superimposed in the same manner. By electrically connecting each portion from the first conductor pipe to the n-th conductor pipe, the first conductor pipe to the n-th conductor pipe are made into a single conductor pipe with electrical continuity, and each conductor pipe is electrically connected. Connect each cooling water supply pipe to the pipe,
Preferably, the coil portion is configured such that cooling water is supplied independently to each conductor pipe.

The other magnetic pole part 3B also has the same configuration as the magnetic pole part 3A.

One semi-cylindrical yoke 4A of the yoke portions 5
As shown in Figures 1, 2 and 4,
connected and arranged along the back side of the magnetic pole part 3A,
Further, a cutout 4C is provided below the center to expose an upper end group 7C and a lower end group 7D formed by the ends 7A and 7B of the plurality of conductor pipes 7. . Further, a total of four supporting pieces 10 are formed protrudingly on the inner peripheral surface side of the semi-cylindrical yoke 4A and near the joint end surface 4C to the other semi-cylindrical yoke 4B, and each of these supporting pieces 1
0, the coil portion 8 is connected to this semi-cylindrical yoke 4A.
It has come to be supported in an integrated manner.

The other semi-cylindrical yoke 4B is also constructed in the same manner as the semi-cylindrical yoke 4B.

These semi-cylindrical yokes 4A and 4B are
As shown in FIGS. 2 and 4, the positioning pin 11 provided on each joint end surface 4C and this pin 1
While being positioned by the hole corresponding to 1, the joining end surfaces 4C are brought into close contact with each other, and, for example, a threaded portion provided on the joining end surface 4C of the semi-cylindrical yoke 4A,
A cylindrical magnetic path is formed as a whole by screwing together a tightening bolt 13 inserted into a hole extending from the outer periphery of the other half-cylindrical yoke 4B toward its joint end surface 4C.

In FIGS. 1 and 2, 13A is a lifting ring attached to the upper ends of both semi-cylindrical yokes 4A and 4B.

Next, the cooling medium supply section 6 will be explained. The cooling medium supply section 6 includes a supply pipe 14 and a discharge pipe 15 that are vertically attached to the outer circumference of the semi-cylindrical yoke 4A, and that are attached from the supply pipe 14 to each of the notches 4D shown in FIG. In order to supply a cooling medium to each manifold section 16, a group of cooling medium supply pipes 17A and 17B are formed of an insulating material and are made up of a plurality of pipes, and from each manifold section 16 to the discharge pipe 15. In order to return the cooling medium, a group of cooling medium return pipes 18 are made of an insulating material and are made up of a plurality of pipes.
A, 18B, and in each manifold section 16, the pipe groups 17A, 17B are connected to the lower end group 7.
In D, the pipe groups 18A and 18B are connected to the upper end group 7C by screwing, respectively.

In addition, in FIG. 2, 19 is a pressure gauge attached to the supply pipe 14, 20 is a flow meter attached to the supply pipe 14,
21 is a thermostat.

The energizing means has a pair of electrode plates 22 and 23 provided in each manifold part 16, and for example, the direction of the magnetic flux by the magnetic pole parts 3A and 3B is set to X as shown in FIG.
When setting in the direction, one electrode 22 connected to the upper end group 7C is set as a + (plus) electrode, and the other electrode 23 connected to the lower end group 7D is set as a - (minus) electrode. It is designed to be connected to a DC power supply (not shown). By establishing such a connection state, it is possible to generate a converging magnetic flux force in the X direction from the coil section 8 on the magnetic pole section 3A side to the coil section 8 on the magnetic pole section 3B side, as briefly shown in Fig. 5. can.

Next, the operation of the device having the above configuration will be explained.

First, this apparatus is assembled in the state shown in FIGS. 1 and 2, and the silicone crystal pulling furnace is inserted into the furnace storage space 2.

Then, supply pipe 14 → pipe group 17A, 17B
A cooling medium is passed through this device through a flow path connecting each conductor pipe 7→pipe groups 18A, 18B→discharge pipe 15, and a predetermined current is passed through each coil portion 8 in the above-described energization manner. As a result, a converging magnetic flux in the X direction (horizontal direction) is applied to the crystal pulling furnace in the insertion space 2, as shown schematically in FIG. This convergent magnetic flux is convergent toward the center compared to the parallel magnetic flux of conventional equipment, so the magnetic flux density for the crystal pulling furnace is improved, which increases the Lorentz force based on the principle described above, and produces high-quality products. It becomes possible to generate crystals.

In addition, this device is constructed in a cylindrical shape that corresponds to the outer circumferential shape of the crystal pulling furnace, so there are no wasted parts, and since it forms a cylindrical magnetic path, the occupied area can be reduced and the overall It is possible to reduce the weight.

Furthermore, the yoke part 5 is a pair of semi-cylindrical yokes 4
Since it is constructed by joining A and 4B, the assembly process of this device is simplified.

Although one embodiment of this invention has been described in detail above, this invention is not limited to the above embodiment, and various modifications can be made within the scope of the gist.

For example, in addition to forming the magnetic pole part and the yoke part in a cylindrical shape, they can also be formed into a shape corresponding to various external shapes of the crystal pulling furnace, such as an elliptical cylinder shape or a cylindrical shape approximating these.

[Effect of idea]

According to this invention detailed above, the opposed surfaces of a pair of coil parts are shaped to correspond to the outer peripheral surface of the object, and the shape of the yoke part is formed into a cylindrical shape corresponding to the outer peripheral shape of the object. As a result, the overall size and weight can be reduced, and a horizontal magnetic field with a high magnetic flux density can be applied to the object to which the magnetic field is applied. Therefore, when this electromagnetic device is applied to a silicone crystal pulling furnace, it is possible to apply a uniform and high-density magnetic field to molten silicone, thereby making it possible to pull crystalline silicone with high purity.

[Brief explanation of drawings]

Figure 1 is a plan view of an embodiment of this invention;
The figure is a side view of the same device, FIG. 3 is a front view of the manifold section of the same device, FIG. 4 is a perspective view of the magnetic pole section and yoke section, and FIG. 5 is a simplified view of the winding state of the coil section of the same device. FIG. 6 is a plan view of the conventional device, and FIG. 7 is a front view of the conventional device. 1... Electromagnetic device, 3A, 3B... Magnetic pole part, 5
... Yoke section, 6 ... Cooling medium supply section, 7 ... Conductor pipe, 8 ... Coil section, 9 ... Magnetic core.

Claims (1)

[Claims for Utility Model Registration] (1) Protrudingly opposing magnetic pole portions are formed on the inner circumferential surface of a cylindrical yoke portion, and a coil portion is disposed on the circumferential side of each of the magnetic pole portions, An electromagnet device characterized in that a facing surface and a facing surface of the coil portion are formed into curved surfaces along an outer circumferential surface of an object to which a magnetic field is applied. (2) The coil part is a pipe wound around a magnetic pole part formed protruding from a cylindrical yoke part, and cooling water is allowed to flow through the pipe. Electromagnetic devices as described in scope paragraph (1). (3) The yoke portion has a shape selected from a cylindrical shape, an elliptical cylindrical shape, or a shape similar to these.
Electromagnetic device described in paragraph (2). (4) The electromagnet device according to claim (3), wherein the yoke portion is cylindrical. (5) The yoke portion according to any one of claims (1) to (4) of the utility model registration claim, wherein each of the yoke portions is formed so as to be able to be divided into two while holding each of the coil portions. Electromagnetic device.