JP2946933B2 - Single crystal pulling device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CZ (Czochralski)
The present invention relates to a single crystal pulling apparatus by a method.

[0002]

2. Description of the Related Art Conventionally, the CZ method suitable for producing a large-diameter cylindrical silicon single crystal rod is a method in which a silicon single crystal seed crystal is immersed in a silicon melt, and the seed crystal is gradually pulled up while rotating. This is for growing a large-diameter silicon single crystal rod having the same crystal orientation as the crystal. In this case, a so-called Dash's neck, in which the silicon single crystal rod is once narrowed down and then thickened when growing from the seed crystal so that the dislocation existing in the seed crystal does not propagate into the silicon single crystal rod. Is formed to eliminate dislocations in the silicon single crystal rod. The diameter of this dash neck is 3 to 4 mm, and its length is several tens.
mm, and its mechanical strength was 100 to 200 kgf. This strength is the tensile strength of a silicon single crystal rod. If a torsion or lateral force is applied to the silicon single crystal rod being pulled, the dash neck will be broken and the silicon single crystal rod will fall into the silicon melt, and the single crystal pulling device There is a danger of breakage, outflow of silicon melt, steam explosion, etc., which may lead to personal injury.

A single crystal pulling apparatus for preventing such a danger is disclosed in, for example, JP-A-63-2529.
No. 91 or JP-A-62-288191. As shown in FIG. 4, a single crystal pulling apparatus disclosed in Japanese Patent Application Laid-Open No. 62-288191 discloses a clamp arm capable of gripping the constriction 102 after forming a constriction 102 in a shoulder 101 of a silicon single crystal rod 100. 103. By pulling up the silicon single crystal rod 100 while holding the tip of the clamp arm 103 in the constriction 102, a heavy silicon single crystal rod having a large diameter and a large diameter can be manufactured safely.

[0004]

However, in such a conventional single crystal pulling apparatus of the CZ method, the tip of the clamp arm 103 is locked to the constriction 102 of the silicon single crystal rod 100, and the silicon Since the single crystal rod 100 is supported, a constriction 102 must be formed in the shoulder 101 of the silicon single crystal rod 100 in advance. Therefore, the control of the pulling speed of the silicon single crystal rod 100, the temperature of the silicon melt 104, etc.
There was a problem that this had to be changed and this change was very difficult.

Accordingly, an object of the present invention is to provide a single crystal pulling apparatus provided with a mechanism capable of supporting a silicon single crystal rod without forming a constriction on the silicon single crystal rod.

[0006]

According to a first aspect of the present invention, there is provided a single crystal pulling apparatus, wherein a crucible for holding a crystal melt and a single crystal rod having a substantially constant radius are pulled from the crystal melt. In a single crystal pulling apparatus including a mechanism, and a holding mechanism interlocked with the pulling mechanism and supporting the single crystal rod, the holding mechanism engages with a side wall of the single crystal rod to form the single crystal rod. It has a first lever unit that supports a crystal rod, and a second lever unit that operates the first lever unit in conjunction with the lifting mechanism.

Further, in the single crystal pulling apparatus according to the present invention, the holding mechanism has a booster unit, and the operation of the second lever unit is controlled by the first lever via the booster unit. This is transmitted to the lever unit.

According to a third aspect of the present invention, in the single crystal pulling apparatus, the pulling mechanism includes a first pulling unit connected to a dash neck of the single crystal rod and capable of moving up and down;
A second lifting unit capable of moving up and down independently of the lifting unit and operating the second lever unit.

According to a fourth aspect of the present invention, in the single crystal pulling apparatus, the pulling mechanism includes rotating means for rotating the single crystal rod around its axis, and the first pulling unit and the first pulling unit. The second lifting units each have a lifting motor, and these lifting motors are held by the rotating means.

In the single crystal pulling apparatus according to the present invention, the first pulling unit and the second pulling unit each have a wire, and the wire is prevented from being twisted. It has a body.

In the single crystal pulling apparatus according to the present invention, the holding mechanism has a supporting member rotatably provided in a horizontal plane, and the supporting member includes the first lever unit and the first lever unit. The second lever unit is supported.

[0012]

In the single crystal pulling apparatus according to the first aspect of the present invention, the single crystal rod is pulled up by a pulling mechanism.
At the time of the lifting, the second lever unit of the holding mechanism is linked with the operation of the lifting mechanism. The first lever unit operates in conjunction with the lever movement of the second lever unit.
The first lever unit makes a lever movement and engages with the side wall of the single crystal rod to hold the single crystal rod.

Further, in the invention according to claim 2,
The second lever unit of the holding mechanism is linked with the operation of the lifting mechanism. By the leverage of the second lever unit, the booster unit is interlocked, and the leverage force of the second lever unit is multiplied. The first lever unit is linked to the operation of the booster unit. As a result, the holding force of the single crystal rod can be further stabilized. Further, by changing the boosting factor of the boosting unit, it is possible to realize the holding corresponding to the weight of the single crystal rod to be pulled up.

Further, in the single crystal pulling apparatus according to the third aspect of the present invention, the second pulling unit moves up and down without being affected by the vertical movement of the first pulling unit. Then, the second lever unit is operated based on the operation of the second pulling unit, and the single crystal rod is held. As a result, the pulling of the single crystal rod and the holding of the single crystal rod can be controlled independently of each other. Therefore, the single crystal rod can be held without hindering the pulling of the single crystal rod.

Further, in the single crystal pulling apparatus according to the present invention, the first pulling unit and the second pulling unit can have the same rotational speed and direction. . Therefore, the single crystal rod can be held without adversely affecting the pulling of the single crystal rod.

In the single crystal pulling apparatus according to the present invention, since the twist preventing body is provided, the wire of the first pulling unit and the wire of the second pulling unit are entangled. There is no. The pulling of the single crystal rod by the first pulling unit is not affected by the holding of the single crystal rod via the second pulling unit. Further, the position where the first lever unit is locked to the single crystal rod does not shift due to the pulling of the single crystal rod. Therefore, the holding of the single crystal rod of the first lever unit does not become weak. As a result, the single crystal rod does not fall into the crystal melt.

Further, in the single crystal pulling apparatus according to the present invention, the first lever unit and the second lever unit of the holding mechanism are interlocked with the rotation of the single crystal rod around the axis by the pulling mechanism. The two lever units can be rotated. As a result, the rotation speed and the rotation direction of the single crystal rod and the first lever unit become the same. Therefore, when the single crystal rod is supported by the first lever unit, the wire of the first pulling unit is not twisted. The lateral deformation of the single crystal rod due to this twist can be prevented. Therefore, the single crystal rod can be supported without adversely affecting the pulling of the single crystal rod.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of a single crystal pulling apparatus according to one embodiment of the present invention.

As shown in this figure, a chamber (not shown)
Inside, the crucible shaft 1 is provided so as to be rotatable and vertically movable. A cylindrical graphite susceptor 2 with a bottom is fixed to the upper end of the crucible shaft 1. A quartz crucible 3 is detachably held in the graphite susceptor 2. The quartz crucible 3 also has a bottomed cylindrical shape. In the quartz crucible 3, a silicon melt 4 in a melt state is injected and held. Outside the graphite susceptor 2, a heater 5 for heating the silicon melt 4 is provided so as to surround the graphite susceptor 2. Further, above the quartz crucible 3, a pulling mechanism 6 for pulling a silicon single crystal rod having a substantially constant radius (for example, a diameter of 8 inches).
Is provided.

The lifting mechanism 6 is provided above the quartz crucible 3 and has a rotatable head 7. The head 7 is fixedly provided with a main motor 9 for winding one main wire 8 and a sub motor 11 for winding two sub wires 10 respectively. This main wire 8
The direction is changed by the main roller 12 and descends toward the lower silicon melt 4. A part (intermediate part) of the main wire 8 hung in this manner is a disc-shaped twist prevention ring 16.
The portion of the main wire 8 below the fixed portion is penetrated downward through the hole 19 of the elevating ring 18. At the lower end of the main wire 8, a seed crystal 14 of silicon single crystal is attached via a seed chuck 13.

As shown in FIG.
Numeral 6 is a disk-like shape, in which two holes 17 are formed corresponding to the sub-wires 10. The main wire 8 is fixed at the center of the torsion prevention ring 16 as described above.
The two holes 17 are formed so as to face each other with the central portion (the fixing portion of the wire 8) interposed therebetween. The twist preventing ring 16 prevents the auxiliary wire 10 from being twisted with respect to the main wire 8 between the head 7 and the elevating ring 18. The main wire 8 is located above the quartz crucible 3
It moves up and down while rotating in the opposite direction.

The sub-wires 10 are also lowered toward the quartz crucible 3 via the sub-roller 15 by the sub-motor 11. These auxiliary wires 10 pass through the two holes 17 of the twist preventing ring 16 respectively, and are fixed to the upper end of the elevating ring 18 rotatable together with the auxiliary wire 10 without contacting the main wire 8. ing. That is, the elevating ring 18 can freely move with respect to the main wire 8, and the torsion preventing ring 16 can freely move with respect to the sub-wire 10.

Above the quartz crucible 3 and below the head 7,
A holding mechanism 20 for supporting the weight of the silicon single crystal bar is provided. The holding mechanism 20 is configured to interlock with the elevating ring 18 of the lifting mechanism 6 as described later.
That is, the holding mechanism 20 has the crystal engaging device 21 formed of a cylindrical body having an axis extending in the vertical direction. The crystal engaging device 21 is supported by a horizontal support plate 23 fixed to the chamber via a bearing 22 so as to be rotatable around its axis.

As shown in FIG. 2, this crystal engaging device 21
The supporting members 28, 31, 34, and 37 are sequentially fixed to the inner peripheral wall at predetermined intervals from top to bottom.
The support members 28, 31, 34, and 37 have a rod-shaped upper hook 24, an upper rod 25, a lower rod 26, and a rod-shaped lower hook 27, respectively. Axle-mounted. Specifically, the upper hook 24 has one end thereof axially attached to the support member 28,
One end of the first wire 30 is fixed and connected to the other end. The other end of the first wire 30 is connected to one end of the upper operating rod 25. The other end of the upper lever 25 is attached to one end of a link 33 which is a rigid body. The other end of the link 33 is pivotally attached to one end of the lower operating rod 26. One end of a second wire 36 is connected to the other end of the lower operating rod 26, and the other end of the second wire 36 is connected to one end of the lower hook 27. The other end of the lower hook 27 is rotatably supported by the support member 37 via the axis 38 as described above.

Further, in the upper operating lever 25, the shaft center 32
The distance between the shaft 32 and the link 33 is set larger than the distance between the first wire 30 and the link with the first wire 30, and the leverage allows boosting. Similarly, the lower operating rod 26 also has a boosting action in accordance with the ratio of the distance between the shaft 35 and the connection with the link 33 and the distance between the shaft 35 and the connection with the second wire 36. Things. That is, in this holding mechanism 20, by appropriately setting the leverage ratio of the upper and lower operating rods 25 and 25, the silicon single crystal rod 40 is provided with a desired boost.
Can be supported.

These movements are as follows. First, when the upper hook 24 rotates clockwise about the axis 29 in FIG. 2, the upper operating rod 25 moves about the axis 32 through the first wire 30. It turns counterclockwise in FIG. As a result, the lower operating lever 26 rotates clockwise about the axis 35 via the link 33 in FIG. Accordingly, the lower hook 27 also rotates clockwise in FIG. 2 about the axis 38 via the second wire 36. At this time, the projection 39 at one end (tip) of the lower hook 27 is connected to the body surface 41 of the silicon single crystal rod 40.
To contact and engage from below to completely hold it. The force for holding the silicon single crystal rod 40 is caused by the leverage of the upper and lower operating rods 25 and 26, respectively.
4 is a multiple of the rotating force.

As described above, when the silicon single crystal rod 40 is held by the lower hook 27, the bearing 2
The crystal engaging device 21 is rotatably supported about a vertical axis through the second member 2. Therefore, the crystal engaging device 21 and the holding mechanism 20 rotate as a whole with respect to the elevating ring 18, and the rotation speed and the rotation direction are the same. Therefore, the main wire 8 is not twisted by the holding of the silicon single crystal rod 40 by the holding mechanism 20. Further, the silicon single crystal rod 40
Can be prevented from shaking. The holding mechanism 20 includes an upper hook 24 that supports the silicon single crystal rod 40, a lower hook 27 that operates the upper hook 24, and a lower hook 27.
Operation of the booster unit that transmits the operation of the upper hook 24 to the upper hook 24, and the upper hook 24 and the upper
5, a lower engaging rod 26 and a lower hook 27 are supported, and the crystal engaging device 21 is provided rotatably in a horizontal plane.

Next, a method of pulling a silicon single crystal rod will be described. Prior to pulling, high-purity polycrystalline silicon and small pieces of silicon crystal doped with boron at a high concentration are put in a quartz crucible 3 in the graphite susceptor 2.
These are all attached to the crucible shaft 1. After the inside of the chamber is evacuated with a vacuum device, argon gas is supplied to the chamber to make the inside of the chamber an argon atmosphere of 10 to 20 Torr.
The heater 5 is energized to heat the quartz crucible 3 to melt the raw material such as silicon. Then, a silicon single crystal seed crystal 14 is attached to the seed chuck 13, and the seed crystal 14 is brought into contact with the center of the liquid surface of the silicon melt 4. Simultaneously with this contact, the crucible shaft 1 is rotated in one direction by a motor at a predetermined crucible rotation speed, and the head 7 of the lifting mechanism 6
The seed crystal 14 is slowly raised while rotating in the other direction at a predetermined crystal rotation speed.

Then, a dash neck is formed continuously at the lower end of the seed crystal 14. The diameter of the large diameter portion of the dash neck is 10 mm, and the diameter of the small diameter portion is 3 mm. Thereafter, the pulling speed of the main wire 8 is reduced and the diameter of the silicon single crystal rod 40 is increased to form a shoulder. Thereafter, by changing the pulling speed and the like, the silicon single crystal rod 40
(For example, a diameter of 200 mm) is formed. At the time of this pulling, the torsion preventing ring 16 fixed to the sub-wire 10 is attached with the pulling growth of the silicon single crystal rod 40.
And the elevating ring 18 fixed to the main wire 8 are raised at a predetermined interval while rotating in the same rotation speed and the same direction. At this time, the upper hook 24 of the holding mechanism 20 is positioned so as to be horizontal. Next, lift ring 1
When the lower portion of the hook 8 contacts and engages with the other end of the upper hook 24 of the holding mechanism 20, the upper hook 24 starts to rotate clockwise in FIG. In conjunction with this rotation, the upper operating lever 25 rotates in the counterclockwise direction, the lower operating lever 26 rotates in the clockwise direction, and the lower hook 27 also rotates in the clockwise direction.

Then, the other end of the upper hook 24 continues to be engaged with the lower part of the elevating ring 18, so that the crystal engaging device 21 rises while rotating together with the elevating ring 18. The rising speed of the crystal engaging device 21 by the sub-wire 10 is set faster than the sea drift rate by the main wire 8. The speed at which the crystal engaging device 21 is raised is about 1 to 3 mm before the projection 39 of the lower hook 27 comes into contact with the body surface 41 of the silicon single crystal rod 40, and the sea drift rate is 1.0.
Decelerate to about 2 to 1.2 times. And the lower hook 27
Contact the body surface 41 of the silicon single crystal rod 40. The weight of the silicon single crystal rod 40 and the pulling force of the upper hook 24, the upper operating rod 25, the lower operating rod 26, the lower hook 27, and the like are applied to this contact surface, and the body surface 41 of the silicon single crystal rod 40 and The engagement of the lower hook 27 with the projection 39 is securely held and does not come off. After the engagement, the speed at which the crystal engagement device 21 is raised is set to the same as the sea drift rate. As a result, the crystal engagement device 21
It rotates and rises while supporting the silicon single crystal rod 40.

Therefore, the silicon single crystal rod 40 can be held while being pulled up without forming a projection or an engaging portion on the shoulder of the silicon single crystal rod 40 in advance. Upper Kong 25 or Lower Kong 2 constituting the booster unit
By changing the leverage ratio of the silicon single crystal rod 4
It can be held with a force corresponding to zero weight. Also,
The pulling of the silicon single crystal rod 40 and the holding of the silicon single crystal rod 40 can be controlled independently of each other. Therefore, the lower hook 27 can be rotated to hold the silicon single crystal rod 40 without hindering the pulling operation of the silicon single crystal rod 40. Further, the rotation speed and the rotation direction of each of the main wire 8 and the sub-wire 10 can be made the same. Therefore, without adversely affecting the pulling of the silicon single crystal rod 40,
The silicon single crystal rod 40 can be held. Also,
Since the torsion prevention ring 16 is used, the main wire 8 and the sub-wire 10 are not entangled. Therefore, the position where the lower hook 27 of the crystal engaging device 21 is locked to the body surface 41 of the silicon single crystal rod 40 does not shift. As a result, the holding of the silicon single crystal bar 40 by the lower hook 27 does not become weak. Therefore, the silicon single crystal rod 40 does not fall into the silicon melt 4. In addition, diameter 8
The silicon single crystal rod 40 having an inch, a length of 2000 mm and a weight of 150 kgf can be safely pulled up and grown. The pulled silicon single crystal rod has no dislocation and no distortion. It is also possible to pull up the silicon single crystal rod 40 by connecting the lifting ring 18 and the lower hook 27 with a wire without using the upper hook 24, the upper lever 25, and the lower lever 26.

[0032]

As described above, according to the single crystal pulling apparatus according to the present invention, the single crystal rod is held while being pulled up without forming a projection or an engaging portion on the single crystal rod in advance. Can be. Further, it can be held with a force corresponding to the weight of the single crystal rod to be pulled up. Furthermore, the pulling of the single crystal rod and the holding of the single crystal rod can be controlled independently of each other, and the single crystal is lifted and lowered while rotating the pulling mechanism and the holding mechanism in the same rotation speed and the same direction. The single crystal rod can be held without hindering the pulling of the crystal rod. In addition, the first lifting unit and the second lifting unit
Since each pulling wire of the pulling unit does not twist,
In pulling the single crystal rod by the first pulling unit,
The locking position of the first lever unit with respect to the single crystal rod does not shift via the second pulling unit. Further, the holding of the single crystal rod of the first lever unit does not become weak. Therefore, the single crystal rod does not fall into the crystal melt.

[Brief description of the drawings]

FIG. 1 is a sectional view of a single crystal pulling apparatus according to one embodiment of the present invention.

FIG. 2 is a sectional view of a single crystal pulling apparatus according to one embodiment of the present invention.

FIG. 3 is a perspective view of a main part of a single crystal pulling apparatus according to one embodiment of the present invention.

FIG. 4 is a sectional view of a single crystal pulling apparatus according to a conventional example.

[Explanation of symbols]

 Reference Signs List 3 quartz crucible 4 silicon melt (crystal melt) 6 pulling mechanism 7 head (rotating means) 8 main wire (wire of first pulling unit) 9 main motor (pulling motor of first pulling unit) 10 sub Wire (wire of second pulling unit) 11 Sub motor (pulling motor of second pulling unit) 16 Torsion prevention ring 20 Holding mechanism 21 Crystal engaging device (supporting member) 24 Upper hook (second lever unit) 25 Upper handle (power booster unit) 26 Lower handle (power booster unit) 27 Lower hook (first lever unit) 40 Silicon single crystal rod

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C30B 1/00-35/00

Claims (6)

(57) [Claims] 1. A crucible for holding a crystal melt, a pulling mechanism for pulling a single crystal rod having a substantially constant radius from the crystal melt, and a holding mechanism for supporting the single crystal rod in conjunction with the pulling mechanism. A single crystal pulling apparatus, comprising: a first lever unit that engages with a side wall of the single crystal rod to support the single crystal rod; and interlocks with the pulling mechanism. And a second lever unit for operating the first lever unit. 2. The single crystal puller according to claim 1, wherein the holding mechanism has a booster unit, and transmits the operation of the second lever unit to the first lever unit via the booster unit. Upper device. 3. The first lifting mechanism is connected to a dash neck of a single crystal rod and is capable of moving up and down.
A lifting unit, a second lifting unit capable of moving up and down independently of the first lifting unit and operating the second lever unit;
The single crystal pulling apparatus according to claim 1 or 2, comprising: 4. The pulling mechanism has rotating means for rotating the single crystal rod around an axis thereof, and the first pulling unit and the second pulling unit include:
The single crystal pulling apparatus according to claim 3, wherein each of the pulling motors has a pulling motor, and the pulling motors are held by the rotating means. 5. The device according to claim 3, wherein each of the first pulling unit and the second pulling unit has a wire, and a twist preventing body for preventing twisting of the wires is provided. Single crystal pulling device. 6. The holding mechanism has a support member rotatably provided in a horizontal plane, and the first lever unit and the second lever unit are supported by the support member. Item 6. The single crystal pulling apparatus according to any one of Items 5.