JPH05270975A - Single crystal pulling device - Google Patents

Abstract

(57) [Abstract] [Purpose] The mechanism for holding a silicon single crystal ingot is divided into a fixed part and a movable part, and the inertial force of the holding mechanism is reduced to, for example, 8 inches in diameter, 2 m in length, and 150 kg in mass. To provide a single crystal pulling apparatus capable of pulling up a silicon single crystal ingot while completely holding it. [Structure] A quartz crucible 3 holding a silicon melt 4 is provided so as to be rotatable and vertically movable. From the silicon melt 4 to the protrusion 4
A pulling mechanism 6 for pulling up the silicon single crystal ingot 40 having 1 is provided. A holding mechanism 20 that cooperates with the pulling mechanism 6 and supports the single crystal ingot 40 is provided. The holding mechanism 20 includes a crystal engaging device 21 extending in the length direction of the single crystal ingot, a lower hook 27 that locks the projection 41 of the single crystal ingot 40 and supports the single crystal ingot 40, and a crystal. An upper hook 24 that is rotatably provided in a part of the engaging device 21 and that operates the lower hook 27 in conjunction with the lifting ring 18 of the lifting mechanism 6 is provided.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, the CZ method, which is suitable for producing a large-diameter cylindrical silicon single crystal ingot, is a method of immersing a silicon single crystal seed crystal in a silicon melt and gradually pulling the seed crystal while rotating the seed crystal. A large-diameter silicon single crystal ingot having the same crystal orientation as the crystal is grown. In this case, in order to prevent the dislocations existing in the seed crystal from propagating into the silicon single crystal rod, when growing from the seed crystal, the silicon single crystal rod is once narrowed and then thickened, so-called Dash's neck. To form dislocation-free silicon single crystal rods. 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 the silicon single crystal rod. If a twisting or lateral force is applied to the silicon single crystal rod being pulled, the dash's neck will be damaged and the silicon single crystal rod will fall into the silicon melt. There is a risk of damage to equipment, outflow of silicon melt, steam explosion, etc., which could lead to personal injury.

Therefore, as a single crystal pulling apparatus for preventing such a danger, for example, Japanese Patent Laid-Open No. 63-252 has been proposed.
No. 991, or those disclosed in JP-A-62-288191. JP-A-62-288191
As shown in FIG. 8, the single crystal pulling apparatus of Japanese Patent Publication is provided with a clamp arm 103 capable of holding the neck 102 after forming the neck 102 in the shoulder 101 of the silicon single crystal rod 100. Is. By pulling up the silicon single crystal ingot 100 while locking the tip of the clamp arm 103 to the constriction 102, a large weight and large diameter silicon single crystal ingot can be safely manufactured.

[0004]

However, in such a conventional CZ method single crystal pulling apparatus, it is difficult to make the shape of the constriction 102 of the silicon single crystal rod 100 constant, and When the constriction 102 is locked, the entire clamp arm 103 is rotating with its base end as the starting point, as indicated by the arrow in the figure. Because of these
If the position where the clamp arm 103 locks the constriction 102 is not accurately controlled, the silicon single crystal ingot 100 cannot be sufficiently held and eventually the silicon single crystal ingot 100 is dropped. That is, since the inertia force of the clamp arm 103 is large in the gripping operation, there is a problem that the position where the clamp arm 103 completely locks the constriction 102 cannot be precisely controlled.

Therefore, the present invention provides a single crystal pulling apparatus capable of reducing the inertial force of the holding mechanism by dividing the mechanism for holding the silicon single crystal ingot into a fixed portion and a movable portion. To that end.

[0006]

In a single crystal pulling apparatus according to a first aspect of the present invention, there is provided a crucible for holding a crystal melt, and a single crystal rod having a projection partly from the crystal melt. In a single crystal pulling apparatus provided with a pulling up mechanism for pulling up and a holding mechanism for supporting a single crystal ingot in association with this pulling up mechanism, the holding mechanism locks a protrusion of the single crystal ingot. It has a 1st lever unit which supports a single crystal ingot, and a 2nd lever unit which interlocks with the above-mentioned pulling mechanism and interlocks the 1st lever unit.

Further, in the single crystal pulling apparatus according to the second aspect, the pulling mechanism is a first pulling unit which is connected to a dash neck of a single crystal rod and is capable of moving up and down, and the first pulling unit.
A second lifting unit that can be raised and lowered independently of the lifting unit and operates the second lever unit.

Further, in the single crystal pulling apparatus according to the third aspect, the pulling mechanism has a rotating means for rotating the single crystal rod about its axis, and the first pulling unit and the above pulling unit. Each of the second pulling units has a pulling prime mover, and these pulling prime movers are held by the rotating means.

Further, in the single crystal pulling apparatus according to the fourth aspect, the first pulling unit and the second pulling unit each have a wire, and twist prevention for preventing twisting of these wires is provided. It has a body.

Further, in the apparatus for pulling a single crystal according to claim 5, the holding mechanism has a support member rotatably provided in a horizontal plane, and the support member includes the first lever unit and the lever member. The second lever unit is supported.

[0011]

In the single crystal pulling apparatus according to the first aspect of the present invention, the single crystal rod is pulled up by the pulling mechanism.
During this pulling up, the second lever unit of the holding mechanism interlocks with the operation of the pulling up mechanism. The lever movement of the second lever unit causes the first lever unit to interlock.
The first lever unit performs a lever movement to lock the projection of the single crystal rod and hold the single crystal rod. The inertial force generated in the first lever unit when holding the single crystal ingot can be reduced more than when the whole holding mechanism holds the single crystal rod. As a result, the position where the first lever unit of the holding mechanism locks the single crystal rod can be precisely controlled.

In the single crystal pulling apparatus according to the second aspect of the invention, the second pulling unit moves up and down without being affected by the lifting movement of the first pulling unit. Then, the second lever unit operates based on the operation of the second pull-up unit, and the single crystal ingot is held. As a result, the pulling of the single crystal ingot and the holding of the single crystal ingot can be controlled independently of each other. Therefore, the single crystal ingot can be held without hindering the pulling up of the single crystal ingot.

In the single crystal pulling apparatus according to the third aspect of the invention, the first pulling unit and the second pulling unit can have the same rotation speed and rotation direction. .. Therefore, the single crystal rod can be held without adversely affecting the pulling of the single crystal rod.

Further, in the single crystal pulling apparatus according to the invention described in claim 4, since the twist preventing body is provided, the wire of the first pulling unit and the wire of the second pulling unit are entangled with each other. There is no. The pulling of the single crystal ingot by the first pulling unit is not influenced by the holding of the single crystal ingot through the second pulling unit. Further, the position where the first lever unit is locked to the projection of 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 fifth aspect of the invention, the first lever unit and the first lever unit of the holding mechanism are interlocked with the rotation of the single crystal rod around the axis by the pulling mechanism. 2 The lever unit can be rotated. As a result, the single crystal rod and the first lever unit have the same rotation speed and rotation direction. Therefore, when the single crystal rod is supported by the first lever unit, the wire of the first pulling unit does not twist. Lateral wobbling of the single crystal rod due to this twist can be prevented. Therefore, the single crystal ingot can be supported without adversely affecting the pulling of the single crystal ingot.

[0016]

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 an embodiment of the present invention.

As shown in this figure, a chamber (not shown)
Inside, a crucible shaft 1 is provided in an upright state so as to be rotatable and to move up and down. A cylindrical graphite susceptor 2 having 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. This quartz crucible 3 also has a bottomed cylindrical shape. A silicon melt 4 in a melted state is injected and held in the quartz crucible 3. A heater 5 for heating the silicon melt 4 is disposed outside the graphite susceptor 2 so as to surround the graphite susceptor 2. Further, above the quartz crucible 3, a pulling mechanism 6 for pulling up a silicon single crystal ingot having a substantially constant radius (for example, a diameter of 8 inches).
Is provided.

The pulling mechanism 6 is provided above the quartz crucible 3 and has a rotatable head 7. A main motor 9 for winding one main wire 8 and a sub motor 11 for winding two sub wires 10 are fixedly mounted on the head 7. This main wire 8
The main roller 12 changes its direction and descends toward the lower silicon melt 4. A part (intermediate part) of the main wire 8 suspended in this way is a disc-shaped twist prevention ring 16
The main wire 8 is fixed to the central portion thereof, and the portion below the fixed portion of the main wire 8 is freely penetrating the hole 19 of the lifting ring 18 and is hung downward. A seed crystal 14 of silicon single crystal is attached to the lower end of the main wire 8 via a seed chuck 13.

As shown in FIG. 7, the anti-twist ring 1
Reference numeral 6 is a disc shape, and two holes 17 are formed corresponding to the sub wire 10. The main wire 8 is fixed at the center of the twist prevention ring 16 as described above.
The two holes 17 are formed so as to face each other with the central portion (fixed portion of the wire 8) interposed therebetween. The twist prevention ring 16 prevents the sub wire 10 from being twisted with respect to the main wire 8 between the head 7 and the lifting ring 18. The main wire 8 is located above the quartz crucible 3 and above the quartz crucible 3
It moves up and down while rotating in the opposite direction.

The auxiliary wires 10 are also lowered toward the quartz crucible 3 by the auxiliary motors 11 via the auxiliary rollers 15. These sub wires 10 are fixed to the upper end of a lifting ring 18 which is rotatable together with the sub wire 10 without coming into contact with the main wire 8 by freely penetrating through the two holes 17 of the twist prevention ring 16. ing. That is, the lifting ring 18 can freely move with respect to the main wire 8 and the twist prevention 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 ingot is provided. The holding mechanism 20 is configured to interlock with the lifting ring 18 of the pulling mechanism 6, as described later.
That is, the holding mechanism 20 has a crystal engaging device 21 formed of a cylindrical body having an axis extending in the vertical direction. The crystal engagement device 21 is supported by a horizontal support plate 23 fixed to the chamber via a bearing 22 so as to be rotatable about its axis.

As shown in FIG. 6, this crystal engaging device 21
An L-shaped upper hook 24 is pivotally attached to the top plate 29 with the bent portion as the center. One end of the upper hook 24 is in contact with the upper end of the stopper 25. This stopper 25
The contact surface of is curvedly formed into a predetermined cam shape. The stopper 25 has a substantially cylindrical shape. The upper end of the movable shaft 26 is fixed to the lower end of the stopper 25. The lower end of the movable shaft 26 is engaged with the long hole 28 of the lower hook 27. The lower hook 27 is also substantially L-shaped. The long hole 28 is formed at one end of the lower hook 27. The bent portion of the lower hook 27 is pivotally attached to a part of the bottom plate 30 of the crystal engaging device 21. A hole 32 is also formed in the middle plate 31 of the crystal engaging device 21. Both ends of the spring 33 are engaged with the upper surface of the intermediate plate 31 and the lower surface of the stopper 25, respectively. This spring 3
The movable shaft 26 moves up and down in the vertical direction by the bias of the spring 33 through the inside 3, the hole 32, and the hole 35 of the pedestal 34. When the movable shaft 26 moves downward, the lower hook 2
When the movable shaft 26 moves upward, the other end 37 of the silicon single crystal 7 faces upward and the other end 37 of the silicon single crystal ingot 40 projects.
It abuts from below and holds it.

Further, as described above, when the silicon single crystal ingot 40 is held by the lower hook 27, the bearing 2
The crystal engaging device 21 is rotatably supported via the axis 2 in the vertical direction. Therefore, the crystal engagement device 21 and the holding mechanism 20 rotate as a whole with respect to the lifting ring 18, and the rotation speed and the rotation direction are the same. Therefore, the main wire 8 is not twisted by holding the silicon single crystal ingot 40 by the holding mechanism 20. Further, the silicon single crystal rod 40 due to this twist
It is possible to prevent sideways shaking. The holding mechanism 20 has an upper hook 24 that supports the silicon single crystal ingot 40, a lower hook 27 that operates the upper hook 24, and the upper hook 24 and the lower hook 27 that are supported and rotate in a horizontal plane. And a crystal engagement device 21 that is provided so as to be possible.

Next, a method of pulling a silicon single crystal ingot will be described with reference to FIGS. Prior to raising
Into a quartz crucible 3 in the graphite susceptor 2, high-purity polycrystalline silicon and small pieces of silicon crystals highly doped with boron are put. The whole of these is attached to the crucible shaft 1. After the inside of the chamber is evacuated by a vacuum device, argon gas is supplied to the inside of 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 silicon or the like. 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 motor rotates the crucible shaft 1 in one direction at a predetermined crucible rotation speed, and the head 7 of the pulling mechanism 6 rotates the seed crystal 14 in the other direction at a predetermined crystal rotation speed. Raise slowly.

At this time, 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's neck is 10 mm, and the diameter of the small diameter portion is 3 mm. After that, the pulling speed of the main wire 8 is decreased and the diameter of the silicon single crystal ingot 40 is increased to form a shoulder.
The maximum diameter of this shoulder is made longer by about 8 mm than the desired body of the silicon single crystal ingot 40 (for example, diameter 200 mm), and the protrusion 41 is formed on the shoulder of the silicon single crystal ingot 40. After that, the pulling speed and the like are changed to form the body of the silicon single crystal ingot 40. At the time of this pulling up, as shown in FIGS. 2 and 3, as the silicon single crystal ingot 40 is pulled up, the twist prevention ring 16 fixed to the sub wire 10 and the lifting ring fixed to the main wire 8 18
And rise while rotating at the same rotation speed and in the same direction at a predetermined interval. Next, as shown in FIGS. 4, 5, and 6, when the lower portion of the lifting ring 18 abuts and engages with the other end of the upper hook 24 of the holding mechanism 20, the upper hook 24 is centered around the bent portion. 6 starts to rotate clockwise in FIG. When the upper hook 24 rotates by a predetermined angle, the stopper 2
The tip of one end of the upper hook 24 is disengaged from the abutting surface 26 of 5. At the same time, the movable shaft 26 whose tip is fixed to the lower end of the stopper 25 by the biasing force of the spring 33.
Moves upwards. According to the movement of the movable shaft 26,
The lower hook 27 fixed to the lower part of the movable shaft 26 rotates by a predetermined angle. The other end of the lower hook 27 (crystal holder) 3
The holding surface 36 of 7 faces the direction of the silicon single crystal ingot 40.
At this time, the holding surface 36 is the protrusion 4 of the silicon single crystal ingot 40.
It is located below the lower surface of 1.

Since the other end of the upper hook 24 continues to be locked to the lower portion of the elevating ring 18, the crystal engaging device 21 ascends while rotating with the elevating ring 18. The ascending speed of the crystal engaging device 21 by the sub wire 10 is set to be higher than the sea drift rate by the main wire 8. The speed of raising the crystal engaging device 21 is about 1 to 3 mm before contact with the lower surface of the shoulder of the silicon single crystal ingot 40, and is reduced to about 1.02 to 1.2 times the sea drift rate. Then, the crystal holder 37 of the lower hook 27 abuts the lower surface 42 of the protrusion 41 of the shoulder whose diameter is larger than that of the body of the silicon single crystal rod 40. After the contact, the speed at which the crystal engaging device 21 is raised is made equal to the sea drift rate. As a result, the crystal engaging device 21 rotates and rises while supporting the silicon single crystal rod 40. The lower hook 27 may be moved from the top to the bottom or in the horizontal direction. The protrusion of the silicon single crystal ingot may be formed in the middle of the shoulder of the conventional silicon single crystal ingot.

When holding the silicon single crystal ingot 40, the lower hook 27 of the crystal engaging device 21 performs a lever movement, but the inertial force of the lower hook 27 is small. The inertial force at this time can be reduced as compared with the case where the whole holding mechanism is used in the related art. Therefore, the position where the holding surface 36 of the lower hook 27 locks the lower surface 42 of the protrusion 41 of the silicon single crystal ingot 40 can be precisely controlled. Further, the pulling of the silicon single crystal ingot 40 and the holding of the silicon single crystal ingot 40 can be controlled independently of each other. Therefore,
The lower hook 27 is rotated without hindering the pulling operation of the silicon single crystal ingot 40 to move the silicon single crystal ingot 40.
Can be held. In addition, the main wire 8 and the sub wire 10 can have the same rotation speed and the same rotation direction. Therefore, the silicon single crystal ingot 40
The silicon single crystal ingot 40 can be held without adversely affecting the pulling up of the silicon single crystal. Further, since the twist prevention ring 16 is used, the main wire 8 and the sub wire 10 are not entangled with each other. Therefore, the position where the lower hook 27 of the crystal engaging device 21 engages with the protrusion 41 of the silicon single crystal ingot 40 does not shift. As a result, the lower hook 27 does not weaken the holding of the silicon single crystal ingot 40. Therefore, the silicon single crystal ingot 40 does not drop into the silicon melt 4. Also, the diameter is 8 inches and the length is 2000.
It is possible to safely pull up and grow a silicon single crystal ingot 40 having a size of 150 mmf and a weight of 150 kgf. The pulled silicon single crystal ingot has no dislocation and no distortion. The upper hook 2
It is also possible to pull up the silicon single crystal ingot 40 by connecting the elevating ring 18 and the lower hook 27 with a wire without using 4.

[0028]

As described above, according to the single crystal pulling apparatus of the present invention, when the projection of the single crystal rod is locked,
Since only the first lever unit of the holding mechanism operates, only a small inertial force acts on this first lever unit.
As a result, the position where the first lever unit locks the single crystal rod can be precisely controlled. Furthermore, pulling up of the single crystal rod and holding of the single crystal rod can be controlled independently of each other, and by raising and lowering the pulling mechanism and the holding mechanism while rotating in the same rotational speed and the same direction,
The single crystal rod can be held without hindering the pulling of the single crystal rod. Further, since the pulling wires of the first pulling unit and the second pulling unit are not twisted,
In pulling the single crystal ingot by the pulling unit, the second
The locking position of the first lever unit with respect to the projection of the single crystal rod does not shift via the 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 drawings]

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

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

FIG. 3 is a sectional view of a single crystal pulling apparatus according to an embodiment of the present invention.

FIG. 4 is a sectional view of a single crystal pulling apparatus according to an embodiment of the present invention.

FIG. 5 is a sectional view of a single crystal pulling apparatus according to an embodiment of the present invention.

FIG. 6 is a sectional view of a single crystal pulling apparatus according to an embodiment of the present invention.

FIG. 7 is a perspective view of a main portion of a single crystal pulling apparatus according to an embodiment of the present invention.

FIG. 8 is a sectional view of a conventional single crystal pulling apparatus.

[Explanation of symbols]

 3 Quartz Crucible 4 Silicon Melt (Crystal Melt) 6 Lifting 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 the second pulling unit) 11 Secondary motor (Pulling prime mover of the second pulling unit) 16 Twist prevention ring 20 Holding mechanism 21 Crystal engaging device (supporting member) 24 Upper hook (second lever unit) 27 Lower hook (1st lever unit) 40 Silicon single crystal rod 41 Projection

Claims (5)

[Claims] 1. A crucible for holding a crystal melt, a pulling mechanism for pulling up a single crystal rod having a projection on a part thereof from the crystal melt, and a single crystal rod supported in cooperation with the pulling mechanism. Holding mechanism to
In the single crystal pulling apparatus including: the holding mechanism, the first lever unit that locks the projection of the single crystal rod and supports the single crystal rod, and the pulling mechanism, A single crystal pulling apparatus, comprising: a second lever unit that interlocks the lever unit. 2. The first pulling mechanism is connected to a dash neck of a single crystal rod and is capable of moving up and down.
A pull-up unit, a second pull-up unit that can be moved up and down independently of the first pull-up unit, and that operates the second lever unit,
The single crystal pulling apparatus according to claim 1, which comprises: 3. The pulling mechanism has rotating means for rotating the single crystal ingot about its axis, and the first pulling unit and the second pulling unit include:
The single crystal pulling apparatus according to claim 2, wherein each pulling prime mover is provided, and these pulling prime movers are held by the rotating means. 4. The first pulling-up unit and the second pulling-up unit each have wires, and a twist prevention body for preventing twisting of these wires is provided. Single crystal pulling device. 5. The holding mechanism includes a support member rotatably provided in a horizontal plane, and the support member supports the first lever unit and the second lever unit. Item 5. The single crystal pulling apparatus according to any one of items 4.