JP4662362B2 - Single crystal pulling device - Google Patents

Description

  The present invention relates to a single crystal pulling apparatus that pulls a single crystal by the Czochralski method (hereinafter referred to as “CZ method”).

  The CZ method is widely used for the growth of silicon single crystals. In this method, the seed crystal is brought into contact with the surface of the silicon melt contained in the crucible, the crucible is rotated, and the seed crystal is pulled upward while rotating in the opposite direction. A single crystal is formed.

  As shown in FIG. 9, in the pulling method using the conventional CZ method, first, raw silicon is loaded into a quartz glass crucible 200 and heated by a heater 201 to form a silicon melt M. Thereafter, the seed crystal P attached to the pulling wire 202 is brought into contact with the silicon melt M to pull up the silicon crystal C.

  In general, prior to the start of pulling, after the temperature of the silicon melt M is stabilized, as shown in FIG. 10, necking is performed in which the seed crystal P is brought into contact with the silicon melt M to dissolve the tip of the seed crystal P. Necking is an indispensable process for removing dislocations generated in a silicon single crystal due to a thermal shock generated by bringing the seed crystal P into contact with the silicon melt M. The neck portion P1 is formed by this necking. The neck portion P1 is generally required to have a diameter of 3 to 4 mm and a length of 30 to 40 mm or more.

In addition, after the start of the pulling, the necking process after the necking is completed, the crown part forming process for expanding the crystal to the diameter of the straight body part, the straight body part forming process for growing the single crystal as the product, and the single body part forming process A tail portion forming step is performed in which the crystal diameter is reduced to a minimum and the lower surface is formed.
A method for producing a silicon single crystal using the CZ method is described in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2005-97049).

By the way, single crystals manufactured by the CZ method have so far been 8 inches in diameter and about 100 kg in weight. However, recently, further increase in diameter has been demanded, and with 12 inch crystals, single crystals reaching 300 kg or more have been manufactured. For this reason, when a large shake occurs due to an earthquake or the like, an external force due to the shake is added to the weight of the single crystal, the neck breaks during the growth of the single crystal without supporting the weight of the single crystal, and the single crystal is The risk of falling into the crucible was high.
In addition, if the single crystal becomes large, the neck may break due to its own weight even if an external force such as an earthquake is not applied, and the single crystal may fall, and it can be safely lifted regardless of the weight of the single crystal. There was a need for a way to do it.

  With respect to such a problem, Patent Document 2 (Japanese Patent Application Laid-Open No. 11-228288) discloses that a constricted portion C2 is formed in a crown portion C1 of a single crystal C as shown in FIG. Discloses a single crystal holding device that prevents the single crystal C from falling. In FIG. 11, the left half shows the state before holding the single crystal with the claw portion 250 closed, and the right half shows the state where the claw portion 250 is in contact with the constricted portion C2 and holds the single crystal C. .

In this single crystal holding device, the claw portion 250 is swingably attached to a holding device main body 252 made of a ring-shaped plate, and is configured to open and close by pulling up or feeding out the wire 251.
When pulling up the single crystal C, the pulling operation is performed with the single crystal C held while the claw portion 250 is closed and brought into contact with the constricted portion C2. Thereby, even if the neck part P1 is cut, the single crystal C can be prevented from falling into the crucible.
Before holding the single crystal C, as shown in the left half of FIG. 11, the holding device main body 252 is supported on the support base 254 via the thrust bearing 253, and the claw portion 250 is brought into contact with the constricted portion. In order to reduce the impact, the wire 251 rotates in the same direction as the single crystal C.

JP-A-2005-97049 Japanese Patent Laid-Open No. 11-228288

However, in the single crystal holding device shown in Patent Document 2, the tip of the claw portion 250 is in contact with the upper tapered surface of the constricted portion C2, as shown in the right half of FIG. Since the stress at the time is concentrated at one point, there is a problem that it is easy to dislocation.
Further, until the single crystal C is held, the holding device main body 252 rotates in the furnace via the thrust bearing 253, and thus there is a possibility that dust is generated in the furnace.

  The present invention has been made under the circumstances as described above, and can prevent the single crystal from falling into the crucible even when the neck portion breaks in the step of pulling up the single crystal. An object of the present invention is to provide a single crystal pulling apparatus that can reduce the possibility of dislocation of crystals.

In order to solve the above-described problems, a single crystal pulling apparatus according to the present invention is a single crystal pulling apparatus that pulls a single crystal from a crucible by the Czochralski method. At least a constriction forming means for forming a constriction in the crown part of the single crystal and a single crystal fall prevention means for preventing the single crystal from dropping into the crucible, wherein the single crystal fall prevention means is provided with a through-hole. A ring main body, an upwardly inclined surface formed on a side surface of the through hole of the ring main body, a ring main body lifting / lowering means for moving the ring main body up and down, and an inclined surface in the through hole can be slid. A plurality of claw portions provided and engageable with the tapered surface on the upper side of the constricted portion; a claw portion lifting / lowering means for moving the plurality of claw portions up and down; the ring main body lifting / lowering means; means Comprising a control means for controlling the operation, and by raising the claw portion against the ring body, the pawl portion slides upward inclined surface, made between a state in which toe is opened, to the ring body On the other hand, by pulling down the claw part, the claw part slides down the inclined surface and the toe is closed, and when the single crystal is pulled, by the control of the control means, The plurality of claw portions are characterized in that a toe is closed so as to be positioned around the constricted portion, and a predetermined gap is formed between the plurality of claw portions without contacting the single crystal.

By being configured in this way, since the claw portion for preventing the single crystal from falling does not come into contact with the single crystal from the growth to the pulling of the single crystal, the dislocation caused by the impact due to the contact is prevented. Can be prevented. Moreover, since the movable part for preventing the single crystal from dropping is only the claw part, dust generation can be suppressed.
In addition, even if the single crystal falls during the pulling of the single crystal due to breaking of the neck portion, etc., the single crystal can be held by the claw portion because the tapered surface on the upper side of the constriction portion is locked to the claw portion. It is possible to prevent the single crystal from falling into the inside.
In addition, even if the single crystal is dislocated during the pulling of the single crystal, the single crystal can be returned to the crucible again without bringing the nail portion and the single crystal into contact with each other, so that it can be easily pulled back (melt back). be able to.

Further, it is desirable that the plurality of claw portions are provided so that a locking surface with respect to the tapered surface is parallel to the tapered surface on the upper side of the constricted portion in a state where the toe is closed.
By doing so, the impact when the single crystal falls can be mitigated, and the contact surface between the claw portion and the single crystal becomes wide, so that the single crystal can be stably held.

In order to solve the above-described problem, the single crystal pulling apparatus according to the present invention includes a pulling means for pulling up the single crystal in the single crystal pulling apparatus that pulls the single crystal from the crucible by the Czochralski method. A constriction forming means for forming a constriction in the crown portion of the single crystal, and a single crystal fall prevention means for preventing the single crystal from falling into the crucible, the single crystal fall prevention means comprising a through hole A ring main body provided with, an inclined surface facing upward formed on a side surface of the through hole of the ring main body, a ring main body lifting / lowering means for moving the ring main body up and down, and sliding on the inclined surface in the through hole A plurality of claw portions that can be locked to the tapered surface on the upper side of the constricted portion, a claw portion lifting means for moving the plurality of claw portions up and down, the ring body lifting means, the plurality of claw portions, and the claw Division Comprising a control means for controlling the operation of the unit, the said by raising the claw portion against the ring body, the pawl portion slides upward inclined surface, made between a state in which toe is opened, the ring By pulling down the claw portion with respect to the main body, the claw portion is configured to slide downward on the inclined surface and to close the toe, and when the single crystal is pulled up, the control means controls Thus, the plurality of claw portions are characterized in that the toe is closed so as to be positioned around the constricted portion, and the single crystal is held by being in surface contact with the single crystal.

  Thus, in the single crystal pulling step, the nail portion is brought into surface contact with the tapered surface on the upper side of the single crystal constriction, so that even a heavy single crystal can be pulled without dropping. it can. Further, when the claw portion and the tapered surface come into contact with each other, stress is dispersed by the surface contact, and the possibility of dislocation formation can be reduced.

In addition, the plurality of claw portions are preferably a pair of claw portions opposed to each other in order to minimize the movable portion.
As described above, since the movable portion can have a minimum configuration as long as the pair of claws are opposed to each other, the cost can be reduced and the possibility of dust generation is also reduced.
Further, before the pulling of the single crystal, the plurality of claw portions are controlled to be in a state in which the toes are opened under the control of the control means, and controlled to stand by in the upper part of the furnace by the claw portion lifting / lowering means. desirable.
By doing in this way, the influence of the deterioration by the heat | fever to a ring main body and a nail | claw part can be avoided.

  According to the present invention, in the step of pulling up the single crystal, even if the neck portion may break, the single crystal can be prevented from falling into the crucible, and the crystal can be dislocated. A single crystal pulling apparatus that can be reduced can be obtained.

Hereinafter, a first embodiment of a single crystal pulling apparatus according to the present invention will be described with reference to the drawings. FIG. 1 is a block diagram schematically showing the configuration of a single crystal pulling apparatus 100 according to the present invention.
The single crystal pulling apparatus 100 is loaded into a furnace body 1 formed by superposing a pull chamber 1b on a main chamber 1a, a quartz glass crucible 2 provided in the furnace body 1, and a quartz glass crucible 2. The heater 3 for melting the semiconductor raw material (raw material silicon) M and the single crystal pulling mechanism 4 (pulling means) for pulling up the single crystal C to be grown while rotating. The single crystal pulling mechanism 4 includes a winding mechanism 4a driven by a motor and a pulling wire 4b wound up by the winding mechanism 4a. A seed crystal P is attached to the tip of the wire 4b via a seed chuck K. ing.

  In addition, the single crystal pulling apparatus 100 is provided with a single crystal fall prevention apparatus 10 in order to prevent the single crystal C from dropping into the crucible 2. The single crystal fall prevention device 10 includes a ring main body 11 made of a ring-shaped plate, and a plurality of claw portions 12 provided so as to be vertically slidable along the inner surface of the ring main body 11. In addition, in this form, in order to minimize a movable part, a pair of (two) nail | claw part 12 which opposes shall be comprised.

  Furthermore, the single crystal fall prevention device 10 includes an elevating mechanism 13 for moving the ring body 11 and the claw portion 12 up and down. The elevating mechanism 13 includes motor-driven hoisting mechanisms 13a and 13b and wires 13c and 13d wound or fed around them, whereby the ring body 11 and the claw portion 12 are moved up and down, respectively.

  Specifically, when the wire 13c is wound up by the winding mechanism 13a, the ring body 11 connected to the tip of the wire 13c is pulled up, and when the wire 13c is drawn out, the ring body 11 is lowered. Further, when the wire 13d is wound up by the winding mechanism 13b (claw part raising / lowering means), the claw part 12 connected to the tip of the wire 13d is pulled up, and when the wire 13d is drawn out, the claw part 12 is lowered. ing.

As shown in FIG. 2, a substantially rectangular through hole 11 a is formed in the ring main body 11, and the pair of claw portions 12 move up and down in the through hole 11. That is, in this through-hole 11a, the opposite side surfaces on the short side are inclined surfaces facing upward, and the pair of claw portions 12 are provided so as to be slidable in the vertical direction.
As an attachment structure of the claw portion 12 to the ring body 11, for example, in the through hole 11a as shown in the drawing, holes 11b for fitting the shaft 14 are formed on opposite side surfaces on the long side, A rail hole 12a is formed in the claw portion 12 along its longitudinal direction. And the shaft 14 is penetrated by the rail hole 12a of the nail | claw part 12, and the both ends are fitted by the hole 11b. As a result, the claw portion 12 slides in the vertical direction within the through hole 11a.

  In this configuration, when the claw portion 12 is pulled up to the maximum extent by the winding mechanism 13b with respect to the ring body 11, the distance dimension H between the two claw portion 12 tips (toe tips) increases as shown in FIG. A pair of nail | claw part 12 will be in the open state. On the other hand, when the claw portion 12 is lowered to the maximum with respect to the ring main body 11, the distance dimension H between the two claw portion 12 tips (tips) becomes small as shown in FIG. Closed state.

A single crystal pulling apparatus 100 shown in FIG. 1 includes a heater control unit 3a that controls the amount of power supplied to the heater 3 that controls the temperature of the silicon melt M, a motor 5 that rotates the quartz glass crucible 2, and a motor. And a motor control unit 5a for controlling the number of rotations of 5.
Furthermore, a wire reel rotation control unit 6 that controls the pulling speed and the number of rotations of the growth crystal and single crystal fall prevention device 10 is provided.
Each of these control units 3a, 5a, 6 is connected to an arithmetic control device 7a (control means) of a computer 7 that performs overall control.

Next, the single crystal pulling process in the single crystal pulling apparatus 100 configured as described above will be described with reference to the process diagrams of FIGS.
First, the raw material silicon M is loaded into the quartz glass crucible 2, and the single crystal growth process is started based on the program stored in the storage device 7 b of the computer 7.

First, the heater control unit 3a is operated by a command from the arithmetic and control unit 7a to heat the heater 3, and the raw material silicon M of the quartz glass crucible 2 is melted.
Further, the motor control unit 5a and the wire reel rotation control unit 6 are operated by a command from the arithmetic control device 7a, the quartz glass crucible 2 is rotated, and the winding mechanism 4a is operated to lower the wire 4b. Then, the seed crystal P attached to the wire 4b is brought into contact with the silicon melt M, and necking for melting the tip portion of the seed crystal P is performed to form the neck portion P1.

Thereafter, the pulling conditions are adjusted by parameters of the power supplied to the heater 3 and the single crystal pulling speed (usually a speed of several millimeters per minute) according to the command of the arithmetic and control unit 7b, as shown in FIG. 4 (a). A crown part forming process and a straight body part forming process are sequentially performed. In the crown portion forming step, the number of rotations of the single crystal C to be grown is controlled by the arithmetic control device 7b (neck forming means) in the crown portion C1 of the single crystal C, thereby forming the neck portion C2.
Also, until the straight body forming step before pulling the single crystal, the ring main body 11 and the claw part 12 with the claw tip opened are located at the upper part in the pull chamber 1b to avoid the influence of heat deterioration, and wait there. State.

Next, when the tail portion forming step for forming the tail portion of the single crystal C is entered, the ring body 11 and the claw portion 12 are lowered to the vicinity of the upper portion of the single crystal C as shown in FIG. In addition, the nail | claw part 12 is made into the state by which the toe | tip was opened until it fell to the position.
When the ring body 11 and the claw portion 12 descend to the vicinity of the upper portion of the single crystal C, the wire 13d is fed out as shown in FIG. 4 (c), and the claw portion 12 is in a state where its claw tip is closed. Here, as shown in FIG. 6, the tips (tips) of the pair of claws 12 are located around the constricted portion C2 of the single crystal C, and the claws 12 are parallel to the tapered surface C3 above the constricted portion C2. Position to be. That is, the claw portion 12 is not in contact with the single crystal C, and a predetermined clearance (gap) is formed between the single crystal C.

Next, when the tail portion C4 is formed, the single crystal C is completely pulled up from the melt M, and is further pulled into the pull chamber 2b by the single crystal pulling mechanism 4 as shown in FIG. Even during the pulling process of the single crystal C, the claw portion 12 and the single crystal C are controlled so as to maintain a certain clearance and do not contact each other as shown in FIG. Then, the ring main body 11 and the claw portion 12 are moved upward in a non-contact manner with the single crystal C in synchronization with the pulling operation of the single crystal C.
Thus, in the single crystal pulling step, the claw portion 12 does not come into contact with the single crystal C even if the claw tip is opened and closed, that is, does not give an impact to the single crystal C, and the single crystal C Can be prevented from being dislocated.

  Further, in the pulling process of the single crystal C, when the neck portion P1 is broken and cut, the single crystal C tends to fall as shown in FIG. However, as shown in FIG. 7, the single crystal C is held without dropping by the tapered surface C3 on the upper side of the constricted portion C2 being engaged with the claw portion 12. Before the neck portion P1 is ruptured (cut), the locking surface of the claw portion 12 is arranged so as to be parallel along the tapered surface C3 above the constricted portion C2, so that the single crystal C falls. However, the impact which the claw part 12 gives to the single crystal C is suppressed to the minimum. Moreover, since the contact surface of the nail | claw part 12 and the single crystal C becomes wide, the single crystal C is hold | maintained stably.

Further, in the pulling process of the single crystal C shown in FIG. 5A, when dislocation occurs due to any cause, the single crystal pulling mechanism 4 stops pulling the single crystal C and performs the lowering operation. That is, the dislocation crystal is returned to the melt M, and the single crystal C is lowered to redraw the crystal (melt back). At this time, the ring main body 11 and the claw portion 12 are also lowered in synchronization, and the claw portion 12 and the single crystal C are controlled to maintain a certain clearance.
And after the operation | work which melt | dissolves to the predetermined | prescribed site | part of the single crystal C is complete | finished, the nail | claw part 12 is opened, the ring main body 11 and the nail | claw part 12 are moved away from the single crystal C, and are moved to a standby position.

As described above, according to the first embodiment of the present invention, the claw portion 12 for preventing the single crystal C from falling does not contact the single crystal C from the growth of the single crystal C to the pulling up. Therefore, it is possible to prevent the formation of dislocation due to the impact caused by the contact. Moreover, since the movable part for preventing the single crystal C from falling is only the claw part, dust generation can also be suppressed.
In addition, even if the single crystal C falls due to breaking of the neck portion during the pulling of the single crystal C, the tapered surface C3 on the upper side of the constricted portion C2 is locked to the claw portion 12, so that the single crystal C is held by the claw portion 12. The single crystal C can be prevented from falling into the crucible 2.
Even if the single crystal C undergoes dislocation during the pulling of the single crystal C, the single crystal C can be returned to the crucible 2 again without bringing the claw portion 12 and the single crystal C into contact with each other. It can be pulled up (melt back).

  Subsequently, a second embodiment according to the present invention will be described. In the second embodiment of the single crystal pulling apparatus according to the present invention, the control method is different from that of the first embodiment, and the mechanical configuration is the same. The same reference numerals are used, and detailed description of the configuration is omitted.

In the second embodiment, in the pulling process of the single crystal C, the same control as in the first embodiment is performed until the tail part forming process of the single crystal C shown in FIG.
In the tail portion forming step, when the ring main body 11 and the claw portion 12 are lowered to near the upper portion of the single crystal C, the wire 13d is fed out as shown in FIG. 4C, and the claw portion 12 is in a state in which the claw tip is closed. It becomes.

Here, the tips (tips) of the pair of claws 12 are positioned around the constricted portion C2 of the single crystal C as shown in FIG. 6, and the claws 12 (the locking surfaces thereof) are tapered above the constricted portion C2. It is located so as to be parallel along the plane C3. That is, the claw portion 12 is not in contact with the single crystal C, and a predetermined clearance (gap) is formed between the single crystal C.
Next, the ring main body 11 and the claw portion 12 are pulled up by the winding mechanisms 13a and 13b, so that the claw portion 12 comes into surface contact with the tapered surface C3 above the constricted portion C2 as shown in FIG. Thereby, the nail | claw part 12 is made into the state holding the single crystal C.

  When the tail portion C4 is formed, the single crystal C is completely pulled up from the melt M, and is further pulled into the pull chamber 2b by the single crystal pulling mechanism 4 as shown in FIG. Even during the pulling process of the single crystal C, as shown in FIG. 8, the claw portion 12 and the tapered surface C3 are in surface contact so that the claw portion 12 can maintain the state of holding the single crystal C. The main body 11 and the claw portion 12 are moved upward in synchronization with the pulling operation of the single crystal C.

  As described above, according to the second embodiment of the present invention, in the single crystal pulling step, the claw portion 12 is brought into surface contact with the tapered surface above the constricted portion of the single crystal C. Even a heavy single crystal can be pulled without dropping. Further, when the claw portion 12 and the tapered surface C3 come into contact with each other, stress is dispersed by the surface contact, and the possibility of dislocation is reduced.

  The present invention relates to a single crystal pulling apparatus that pulls a single crystal by the Czochralski method, and is suitably used in the semiconductor manufacturing industry and the like.

FIG. 1 is a block diagram schematically showing an embodiment of the overall configuration of a single crystal pulling apparatus according to the present invention. FIG. 2 is a view for explaining constituent members of the single crystal fall prevention device included in the single crystal pulling apparatus of FIG. 1. FIG. 3 is a view for explaining the opening and closing operation of the claw portion in the single crystal fall prevention device. FIG. 4 is a process diagram for explaining a single crystal pulling process. FIG. 5 is a process diagram for explaining a single crystal pulling process. FIG. 6 is a diagram for explaining the positional relationship between the claw portion and the single crystal when the single crystal is pulled according to the first embodiment of the present invention. FIG. 7 is a diagram for explaining a state in which a single crystal is held when the single crystal is dropped in the first embodiment according to the present invention. FIG. 8 is a diagram for explaining the positional relationship between the claw portion and the single crystal when the single crystal is pulled according to the second embodiment of the present invention. FIG. 9 is a diagram for explaining a pulling method using the conventional CZ method. FIG. 10 is a diagram for explaining formation of a neck portion in a pulling method using a conventional CZ method. FIG. 11 is a view for explaining a conventional method of forming a constricted portion to prevent a single crystal from falling.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Furnace 1a Main chamber 1b Pull chamber 2 Quartz glass crucible 3 Heater 4 Pulling mechanism (pulling means)
6 Wire reel rotation control unit 7 Computer 7a Arithmetic control device (control means, constriction forming means)
7b Storage device 10 Single crystal fall prevention device 11 Ring body 12 Claw portion 13 Lifting mechanism 13a Winding mechanism 13b Winding mechanism (lifting means)
100 Single crystal pulling device C Single crystal C1 Crown part C2 Constriction part C3 Tapered surface M Raw material silicon, silicon melt P Seed crystal P1 Neck part

Claims (5)

In a single crystal pulling apparatus that pulls a single crystal from a crucible by the Czochralski method,
A pulling means for pulling up the single crystal, a constriction forming means for forming a constriction in the crown portion of the single crystal, and a single crystal fall prevention means for preventing the single crystal from falling into the crucible,
The single crystal fall prevention means includes a ring main body provided with a through hole, an inclined surface facing upward formed on a side surface of the through hole of the ring main body, a ring main body lifting means for moving the ring main body up and down, A plurality of claw portions that are slidably provided on the inclined surface in the through hole and can be locked to the tapered surface on the upper side of the constricted portion; claw portion lifting means for moving the plurality of claw portions up and down; and the ring A main body elevating means, a plurality of claw parts and a control means for controlling the operation of the claw part elevating means ,
By pulling up the claw portion with respect to the ring body, the claw portion slides on the inclined surface upward and the toe is opened, and by pulling down the claw portion with respect to the ring body, the claw portion is It is configured to slide down the inclined surface and close the toe,
When the single crystal is pulled, the plurality of claws are closed so that the toes are located around the constricted portion under the control of the control means, and the single crystal is not in contact with the single crystal without being in contact with the single crystal. A single crystal pulling apparatus characterized by forming a predetermined gap.   2. The unit according to claim 1, wherein the plurality of claw portions are provided so that a locking surface with respect to the tapered surface is parallel to the tapered surface on the upper side of the constricted portion in a state where the toe is closed. Crystal pulling device. In a single crystal pulling apparatus that pulls a single crystal from a crucible by the Czochralski method,
A pulling means for pulling up the single crystal, a constriction forming means for forming a constriction in the crown portion of the single crystal, and a single crystal fall prevention means for preventing the single crystal from falling into the crucible,
The single crystal fall prevention means includes a ring main body provided with a through hole, an inclined surface facing upward formed on a side surface of the through hole of the ring main body, a ring main body lifting means for moving the ring main body up and down, A plurality of claw portions that are slidably provided on the inclined surface in the through hole and can be locked to the tapered surface on the upper side of the constricted portion; claw portion lifting means for moving the plurality of claw portions up and down; and the ring A main body elevating means, a plurality of claw parts and a control means for controlling the operation of the claw part elevating means ,
By pulling up the claw portion with respect to the ring body, the claw portion slides on the inclined surface upward and the toe is opened, and by pulling down the claw portion with respect to the ring body, the claw portion is It is configured to slide down the inclined surface and close the toe,
When pulling up the single crystal, the plurality of claws are closed so that the toes are located around the constricted portion under the control of the control means, and the single crystal is held by being in surface contact with the single crystal. A single crystal pulling apparatus.   The single crystal pulling apparatus according to any one of claims 1 to 3, wherein the plurality of claw portions are a pair of claw portions opposed to each other.   Before the pulling of the single crystal, the plurality of claws are controlled to be in a state in which the toes are opened under the control of the control means, and are controlled to stand by in the furnace upper part by the claw part lifting / lowering means. The single crystal pulling apparatus according to any one of claims 1 to 4.

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