JPH03252386A - Device for producing single crystal - Google Patents

Abstract

PURPOSE:To grow single crystal while continuously feeding a bulky raw material in high accuracy of feed amount by installing a storage column of raw material, a weighing column of receiving the raw material from the storage column and supplying to a crucible and a load cell of measuring the amount of the raw material to be supplied to the crucible in the metering column. CONSTITUTION:A crucible 6 is divided by a partition 2 into a raw material melting part at the outside and a crystal growing part at the inside. A bulky raw material 30 of silicon is supplied to a storage column 22 rotatable around an approximately horizontal central shaft and successively discharged from an opening part of the storage column 22 by rotary motion of the storage column 22. Then the raw material 30 is sent through a chute 25 to a metering column 24 and moved by rotary motion of the inclined metering column 24 to the end at the outlet side of the metering column 24 while controlling the flow rate of the raw material by a load cell 26 laid in the metering column 24. Then the bulky raw material 30 is fed through guide pipes 27 and 28 to the raw material melting part of the crucible 2, melted, introduced through a through hole 7 of the partition 6 of the crucible 2 to a crystal growing part to grow silicon single crystal 12.

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.
(abbreviated as law) is being actively developed. -For example,
There is a special public service No. 61-17537. However, in both cases, it is necessary to control the supply amount of silicon raw materials with high precision;
The shape of the raw material silicon is limited to granular ones 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.
It is in millimeters.

[Problems to be Solved by the Invention] However, the above-mentioned granular silicon raw materials are not widely used, and for the CC-cz method to become widespread, it is necessary to - be able to use raw materials used for boat fishing; The commonly used raw material required for crystal growth technology is an amorphous mass such as crushed ice or glass. Furthermore, it is extremely difficult to cut out such bulk raw material from the storage container and control the amount supplied into the crucible, as the size thereof is large and varies from 10 to 50 mm. Therefore, the cc-cz method using bulk raw materials has not yet been put to 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>).

■Able to supply small amounts (30-100g/win), and
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 problem] Single crystal manufacturing equipment according to the present invention! A crucible containing a melt of a crystal raw material and rotating around a vertical axis, an electric resistance heating means provided around the crucible for heating the crucible, and pulling 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 supplying device for supplying the crystal raw material to the raw material melting section. In a silicon single crystal production apparatus that grows a single crystal while supplying a lumpy raw material, the silicon single crystal manufacturing apparatus has a silicon single crystal manufacturing apparatus that holds the lumpy raw material, has a substantially horizontal central axis, and is rotatable around the central axis. The storage cylinder has an inner diameter that allows the bulk raw material to pass from one end to the other, and is inclined so that the end serving as the outlet is lower than the end serving as the inlet, and the central axis is A raw material supply device is provided, which is rotatable around the measuring cylinder and has a measuring cylinder provided on the downstream side of the storage cylinder, and a load meter attached to the measuring cylinder for measuring the weight of the lumped raw material passing through the measuring cylinder. It is characterized by

[The bulk raw material is held in a storage cylinder whose central axis is approximately horizontal.
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 cylinder.

The metering tube has an inner diameter that allows bulk material to pass from one end to the other. Further, the storage cylinder is provided so as to be inclined so that the end that serves as an inlet for the raw material discharged from the storage cylinder is higher than the other end that serves as an outlet. Therefore, the bulk raw material discharged from the storage cylinder moves from the inlet end to the outlet end while sliding inside the measuring cylinder due to rotational movement around the central axis of the measuring cylinder. As they move, the raw materials are arranged in a line. Finally, they are discharged one by one from the outlet side end. The discharge amount is adjusted by adjusting the rotation speed of the measuring tube. Alternatively, a method of adjusting the inclination angle of the central axis of the measuring cylinder, or a method of combining these methods may be used.

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

■ A method of pivoting the measuring cylinder near the raw material inlet and applying the storage M and L loads to the load cell near the outlet; ■ A method of applying the entire load of the storage cylinder to the load cell. It will be done. The function of the load cell corresponding to the methods (1) and (2) above is as follows.

■The moment a single lump of raw material is discharged, the reading on the load cell placed near the discharge end drops rapidly.0 Each time a lump of raw material is discharged, the reading on the load cell drops rapidly. It happens. The cumulative total of the amount of decrease in this instruction within a predetermined period of time corresponds to the amount of discharge.

■Intermittently charging raw material lumps into the measuring cylinder 0 Each time an individual raw material lump is discharged, the reading on the load cell that supports the entire measuring cylinder 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 lump raw material supplied into the crucible is adjusted by controlling the rotational speed of the measuring tube or the inclination angle of the central axis based on the weight measured by the load cell.

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.

Embodiments] Embodiments 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 as a heating means, and a heat insulating material 9 provided around it are arranged! has been done. 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. 12 is a columnar silicon single crystal grown by the seed crystal 11 and pulled up from the silicon melt 5.

Reference numeral 40 denotes a pulling device, which includes a pulling chamber 1b and a wire 10 to which a seed crystal 11 is attached via a seed chuck.
, 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 is provided at the top of the chamber 1 and communicates with the inside of the chamber 1. A lid 31 for opening and closing when replenishing the bulk silicon raw material 30 is provided at the top of the box body 21, and an O-ring 32 for sealing is provided.
It is bolted to the box body 21 via. Reference numeral 22 denotes a storage cylinder that is provided inside the box body 21 and is rotatable around a central axis by a drive mechanism (not shown), and the inclination angle of the central axis can be adjusted around a tilting cylinder shaft 23. 24 is inclined so that the inlet side end of the silicon bulk raw material 30 is higher than the outlet side end;
This is a measuring cylinder that can be rotated around a central axis 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 measuring cylinder 24 for guiding the silicon lump raw material 30 discharged from the storage cylinder 22 to the measuring cylinder 24. A load meter 26 for measuring the weight of the silicon lump raw material 30 is attached to the measuring cylinder 24 . The moment the silicon block raw material 30 is discharged from the measuring tube 24, the measured value decreases by the weight of the discharged silicon block raw material 30, so the front 1 self-load meter 26 calculates the cumulative value of this decrease within a predetermined time. can be calculated to measure the amount of silicon lump raw material 30 to be supplied to the crucible 2. 27 is a first guide pipe provided below the measuring tube outlet. 28 is gate valve 2
This is a second guide pipe that supplies the raw material to the silicon melt in the raw material melting section through the second guide pipe.

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 amount is equivalent to the amount of single crystal growth.

The silicon lump raw material 30 charged into the storage cylinder 22 is discharged from the opening of the storage cylinder 22 by the rotational movement of the storage cylinder 22 . It is then supplied to the measuring tube 24 via the chute 25. Since the inlet side end of the measuring cylinder 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 measuring cylinder 24 is The movement causes it to move axially within the metering barrel toward the outlet end with a lower height.

The bulk silicon raw material 30 discharged from the outlet end of the measuring tube 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 measuring cylinder 24 moves in the axial direction within the measuring cylinder. Furthermore, the moving speed of the raw material within the measuring cylinder can be adjusted by the rotational speed of the measuring cylinder. Therefore, the input amount is adjusted by adjusting the rotation speed of the measuring cylinder 24 while monitoring the measured value of the load cell 26 attached to the measuring cylinder 24.

When replenishing the silicon lump raw material 30 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, the opening/closing lid 31 on the top of the box 21 is opened and the silicon block raw material 30 is replenished.

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

[Effects of the Invention] According to the single crystal manufacturing apparatus of the present invention, there is provided a raw material storage cylinder, a measuring cylinder that receives the raw material from the storage cylinder and supplies it to the crucible, and a measuring cylinder that measures the amount of the raw material in the measuring cylinder to be 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.

1...Chamber, 1a...Chamber diamond, 1b...Archive chamber, 2...Crucible, 3...Graphite crucible, 4...
...Support shaft, 5...Silicon melt, 6...Partition, 7
...Through hole, 8...Heater, 9...Insulating material, 1o...
- Bow raising wire, 11... Seed crystal, 12... Silicon single crystal, 13. Wire winding device, 14. 29... Gate valve, 2o... Raw material supply device, 21... Box body, 2
2...Storage tube, 23...Tilt axis, 24 River measuring tube, 25
...Chute, 26...Load cell, 27...First guide tube, 28...Second guide tube, 3o...Silicon block raw material, 31...Opening/closing lid, 32...0 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. The storage cylinder has an inner diameter that allows the bulk raw material to pass from one end to the other, and is inclined so that the end serving as the outlet is lower in height than the end serving as the inlet, and has a central axis. a measuring cylinder rotatably provided on the downstream side of the storage cylinder; a load cell attached to the measuring cylinder for measuring the weight of the lumped raw material passing through the measuring cylinder;
1. A single-crystal production device characterized by being provided with a raw material supply device having the following. (2) The single crystal manufacturing apparatus as set forth in claim 1, wherein the storage cylinder and the measuring cylinder are cylindrical in shape. (3) The single crystal manufacturing apparatus as set forth in claims 1 and 2, wherein the storage cylinder and the measuring cylinder are made of Teflon, quartz, or silicon.