JPH03290392A - Single crystal production device - Google Patents

Abstract

PURPOSE:To continuously and stably charge a raw material of non-uniform lumps from the storage cylinder of the raw material into a crucible by disposing a measuring chute on the downstream side of the storage cylinder in a finely shaking state. CONSTITUTION:The single crystal production device is composed of a crucible 2, a heating means 8 for heating the crucible 2, devices 10, 13 for lifting the single crystal 12 from the melted liquid 5, a dividing member 6 having a hole 7 for the passage of the melted liquid 5 and a raw material-feeding device 20. The crucible 2 holds the melted liquid of the crystal raw material 30 and is rotate about a vertical shaft 4. The dividing member 6 divides an outside raw material melting section from an inside crystal-growing section each disposed in the crucible 2. The raw material-feeding device 20 is formed of a storage cylinder 22 for storing the raw material, a measuring chute 24 and a weight-measuring meter 26 attached to the measuring chute 22. The measuring chute 24 is disposed in a finely shakable state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a silicon single crystal manufacturing apparatus for growing a single crystal while supplying bulk raw material.

[Prior art] A method for manufacturing a silicon single crystal (hereinafter referred to as cc-cz) in which a single crystal is continuously grown while continuously supplying raw materials into a crucible.
Continuous ChargeCz
ocbralski) is currently under active development.

- An example is Japanese Patent Publication No. 61-17537.

However, in both cases, the shape of the raw material silicon is limited to granular ones because it is necessary to control the supply amount of the silicon raw material with high precision and because it is easy to cut out the raw material from the storage container. The shape of this granular raw material is spherical, and the diameter is 0.2 to 5 mm.

[Problems to be Solved by the Invention] However, the above-mentioned granular silicon raw materials are not widely used, and in order for the cc-cz method to become widely used, - it is necessary to use raw materials that are numerically used. The commonly used raw material required for crystal growth technology is an amorphous mass such as crushed ice or glass. In addition, it is extremely difficult to cut out such a lumpy raw material from a storage container and control the amount supplied into a crucible because the size of the raw material is large, ranging from 10 to 50 mm, and varies widely. Therefore, the CC-C2 method using bulk raw materials has not yet been put into practical use.

The requirements that the above bulk raw material supply device must meet are as follows.

- Raw materials can be stably cut out from a storage section that stores a large amount of raw materials (50 to 200 kgf).

■Minor amount supply < 30-100 g/win) is possible,
In addition, the supply amount can be controlled with high precision (target value ±10%).

- No contamination of raw materials.To this end, it is desirable that the structure be simple enough that the device can be manufactured from silicon, quartz, or Teflon.

Although a wide variety of methods for conveying bulk objects have been put into practice in fields other than the field of the present application, none of these methods satisfies the above requirements.

The present invention has been made in view of the above circumstances, and an object of the present invention is to manufacture a single crystal, which is equipped with a raw material supply device capable of supplying bulk raw materials continuously and controlling the supply amount with high precision. The purpose is to provide equipment.

[Means for Solving the Problems] A single crystal production apparatus according to the present invention includes a crucible that accommodates a melt of a crystal raw material and rotates around a vertical axis, and a crucible that is provided around the crucible and heats the crucible. It has an electric resistance type heating means, a pulling device for pulling up a single crystal from the melt, and a through hole for the melt, and is provided in the crucible and divided into an outer raw material melting section and an inner crystal growth section. A silicon single crystal production device that has a partition and a raw material supply device that supplies crystal raw materials to the raw material melting section, and grows a single crystal while supplying the raw raw materials, wherein the raw raw materials are held in the raw materials, and the central axis is A storage cylinder that is substantially horizontal and rotatable around the central axis, and is inclined so that the end that serves as the outlet for the lumpy raw material is lower in height than the end that serves as the inlet, and is capable of minute vibrations. The present invention is characterized in that it is provided with a raw material supply device having a weighing gutter provided on the downstream side of the storage cylinder and a load meter attached to the weighing gutter for measuring the weight of the bulk raw material passing through the measuring gutter.

[Operation] The bulk raw material held in the storage cylinder whose central axis is almost horizontal is
Rotational movement about the central axis of the storage cylinder causes the storage cylinder to be discharged from one open end. This cutting method allows the raw material to be cut out without difficulty even though the raw material is extremely irregularly shaped, large, and has large variations in size. Furthermore, the structure is simple. To adjust the cutting amount,
This is done by adjusting the rotation speed of the storage cylinder. Alternatively, a method may be used in which the inclination angle of the central axis of the storage cylinder is adjusted.
Alternatively, a combination of these methods may be used.The raw material cut out from the storage cylinder is fed into the measuring gutter.

The measuring gutter is provided so as to be inclined such that the end serving as the inlet for the raw material discharged from the storage cylinder is higher than the other end serving as the outlet.

Therefore, the lumpy raw material discharged from the storage cylinder moves from the inlet side end toward the outlet side end while sliding inside the metering gutter due to the minute vibrations of the measuring gutter. As they move, the raw materials are arranged in a line.

Finally, they are discharged one by one from the outlet side end. The amount of discharge can be adjusted by the vibration intensity (amplitude, S frequency) of the measuring gutter.
This is done by adjusting the Alternatively, a method of adjusting the inclination angle of the axis parallel to the longitudinal direction of the metering gutter, or
A combination of these methods may also be used. The shape of the metering gutter is preferably a boat-bottom shape, because the lumpy raw materials tend to line up in rows as they move.

A load meter is attached to the weighing gutter, and the weight of the lumpy raw material discharged from the gutter is measured. As for the weighing method, the following two methods can be considered depending on how the weighing gutter load is applied to the load cell.

■A method in which the measuring gutter is pivoted near the raw material inlet and the load of the measuring gutter is applied to a load cell near the outlet.

(2) A possible method is to apply the entire load of the weighing gutter to a load meter. The function of the load cell corresponding to the methods (1) and (2) above is as follows.

0 At the moment when one raw material lump is discharged, the indication on the load cell placed near the discharge end sharply drops.6 Every time an individual raw material lump is discharged, the reading on the load cell suddenly drops. . The cumulative total of the amount of decrease in this instruction within a predetermined period of time corresponds to discharge l.

■Intermittently charging raw material lumps into the measuring gutter 1 Each time an individual raw material lump is discharged, the reading on the load cell that supports the entire measuring gutter decreases. The cumulative total of the amount of decrease in the load cell indication during a predetermined period of time while charging of the raw material block is stopped corresponds to the discharge amount.

The amount of silicon block raw material supplied into the crucible is adjusted by controlling the vibration intensity of the measuring gutter or the inclination angle of the axis parallel to the longitudinal direction based on the weight measured by the loading needle.

This measuring method allows raw materials to be transferred without difficulty even though the raw materials are extremely irregularly shaped and have large variations in size, and therefore the supply amount can be measured and controlled with high precision. Furthermore, the structure is simple.

Since the raw material supply device as described above has a simple structure, the members that come into contact with the silicon raw material can be made of Teflon, quartz, or silicon in order to reduce the contamination of impurities.

[Examples] Examples of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a longitudinal sectional view of the single crystal manufacturing apparatus of this embodiment.

1 is a chamber in which a crucible 2 is provided in the center, and 1a is a lid thereof. In the chamber 1, a support shaft 4 that supports the graphite crucible 3 in a rotatable and vertically movable manner, a heater 8 serving as a heating means, and a heat insulating material 9 provided around the heater are arranged. The crucible 2 is made of quartz and is set within a graphite crucible 3. Reference numeral 6 denotes a partition that divides the silicon melt 5 in the crucible 2 into an outer raw material melting section and an inner crystal growth section. A through hole 7 is provided in the partition 6. Reference numeral 12 denotes a columnar silicon single crystal grown by the seed crystal 11 and pulled from the silicon melt 5.

40 is a pulling device, which includes a pulling chamber 1b and a wire 1 to which a seed crystal 11 is attached via a seed chuck.
0, it is composed of a wire winding device 13 around which the wire is wound, and a gate valve 14.

20 is a raw material supply device. A box body 21 that communicates with the inside of the chamber 1 is provided at the top of the chamber 1 . At the top of this box body 21, there is provided an opening/closing ring 1231 for replenishing the bulk silicon raw material 30, and a ○ ring 3 for sealing.
It is bolted to the box body 21 via 2. 22 is provided inside the box body 21, and is capable of rotational movement around the central axis by a drive (not shown), as well as a tilting shaft 23.
This is a storage cylinder whose inclination angle of the central axis can be adjusted around . 24, the inlet side end of the silicon bulk raw material 30 is
This is a metering gutter that is tilted so that the height is higher than the outlet side end, and allows minute vibration movement by a drive mechanism (not shown).

A chute 25 is provided between the outlet of the storage cylinder 22 and the inlet end of the metering gutter 24 for guiding the silicon block raw material 30 discharged from the storage cylinder 22 to the metering channel @24. A load cell 26 for measuring the weight of the silicon lump raw material 30 is attached to the weighing gutter 24 . The moment the silicon block raw material 30 is discharged from the measuring gutter 24, the measured value decreases by the weight of the discharged silicon block raw material 30, so the bag shape needle 26 measures the cumulative amount of this decrease within a predetermined period of time. By calculation, the amount of silicon bulk raw material 30 to be supplied to the crucible 2 can be measured. 27 is a first guide pipe provided below the weighing machine outlet. 28 is the gate valve 29
A second supplying the raw material to the silicon melt in the raw material melting section through the
It is a guide tube.

Next, the operation of this embodiment configured as described above will be explained. During the growth of the silicon single crystal 12, the raw material supply device 20
A silicon lump raw material 30 is introduced into the silicon melt 5 in the outer raw material melting section divided by the partition 6 through the second guide pipe 28. The l is equivalent to the amount of single crystal growth.

The silicon lump raw material 30 charged into the storage tube 22 is discharged from the opening of the storage tube 22 by the rotational movement of the storage tube 22 . It is then supplied to a weighing machine 24 via a chute 25. Since the inlet side end of the weighing machine 24 is provided so as to be higher than the outlet side end, the silicon lump raw material 30 supplied to the inlet side end of the weighing machine 24 is The oscillatory movement causes it to move axially within the metering trough towards the lower outlet end.

The bulk silicon raw material 30 discharged from the exit end of the weighing machine 24 passes through the first guide pipe 27 and the second guide pipe 28 and is introduced into the silicon melt 5 in the raw material melting section of the crucible 2 . The amount of the silicon lump raw material 30 charged to the silicon melt surface is determined by the speed at which the silicon lump raw material 30 in the weighing machine 24 moves in the axial direction within the weighing machine. Further, the moving speed of the raw material in the weighing gutter can be adjusted by the vibration intensity (amplitude, frequency) of the weighing machine. Therefore, weighing machine 24
The input amount is adjusted by adjusting the vibration intensity of the weighing ai 24 while monitoring the measured value of the load meter 26 attached to the meter.

When replenishing the silicon block WF130 into the storage cylinder 22, the gate valve 29 is closed and the storage cylinder is rotated about the tilting cylinder shaft 23 so that the central axis of the storage cylinder 22 becomes vertical. Next, for opening and closing the upper part of the box body 21! 31 is opened and silicon lump raw material 30 is replenished.

Further, in the raw material supply device 20 according to the present invention, the storage cylinder 22 with which the silicon lump raw material 30 comes into contact, the weighing machine 24,
If the chute 25, the first guide tube 27, the second guide tube 28, etc. are made of Teflon, quartz, or silicon, it is possible to prevent contamination by impurities.

[Effects of the Invention] According to the single crystal manufacturing apparatus of the present invention, a raw material storage cylinder, a weighing machine that receives the raw material from the storage cylinder and supplies it to the crucible, and a weighing gutter measure the amount of the raw material supplied to the crucible. Since a load meter is provided, it becomes possible to grow a silicon single crystal while continuously supplying a bulk silicon raw material, which is generally widely used for growing single crystals, into the crucible.

Lifting chamber, 2... Crucible, 3... Graphite crucible, 4...
...Support shaft, 5...Silicon melt, 6...Partition, 7
...Through hole, 8...Heater, 9...Insulating material, 10.
- Bow raising wire, 11... Seed crystal, 12 - Silicon single crystal, 13... Wire winding device, 14.29... Gate valve, 20... Raw material supply device, 21 - Box body, 22
・・Storage cylinder, 23 ・・Tilting cylinder shaft, 24 ・Weighing machine, 25
Chute, 26 Load cell, 27 First guide tube, 28 Second guide tube, 3o Silicon block raw material, 31 Opening/closing lid, 32 ○ ring , 40・Lifting device.

Claims (3)

[Claims] (1) A crucible that holds a melt of crystal raw material and rotates around a vertical axis, an electric resistance heating means provided around the crucible to heat the crucible, and a single crystal from the melt. a pulling device, a partition having a through hole for the melt and provided in the crucible to divide it into an outer raw material melting section and an inner crystal growth section, and a raw material supply supplying the crystal raw material to the raw material melting section. In a silicon single crystal production device that grows a single crystal while supplying a lumpy raw material, the silicon single crystal manufacturing device has a device that holds the lumpy raw material, has a substantially horizontal central axis, and is rotatable around the central axis. a measuring gutter provided on the downstream side of the storage cylinder, which is inclined so that the end that serves as the outlet for the bulk raw material is lower than the end that serves as the inlet, and is capable of microvibration; 1. A single crystal manufacturing apparatus comprising a raw material supply device having a load meter attached to a weighing gutter for measuring the weight of a lumpy raw material passing through the gutter. (2) The single crystal manufacturing apparatus according to claim 1, wherein the storage cylinder has a cylindrical shape, and the measuring gutter has a boat bottom shape. (3) The single crystal manufacturing apparatus as set forth in claims 1 and 2, wherein the material of the storage cylinder and the measuring gutter is Teflon, quartz, or silicon.