JP3514696B2 - Single crystal pulling device - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a single crystal pulling apparatus for pulling a single crystal such as silicon.

[0002]

2. Description of the Related Art Generally, a method of forming a thin dash neck (hereinafter referred to as a neck portion) under a seed crystal and then directly forming a large-diameter and heavy single crystal (body portion) under the neck portion is known. However, the neck part may not be able to withstand a heavy load and may be broken. Therefore, as a method to prevent this, a diameter expansion part is formed under the neck part, and a small diameter part (constriction part) thicker than the neck part is formed under the diameter expansion part, and the diameter expansion part above this neck part is expanded. By supporting the lower part of the portion by the diameter-enlarged portion support member, while gradually pulling the single crystal at a predetermined speed, the load gradually shifts from the neck portion support to the diameter-enlarged portion support and after the complete transition to the diameter-enlarged portion support. A method of pulling up only by supporting the enlarged diameter portion has been proposed.

As a conventional diameter enlarging portion pulling mechanism for realizing this method, for example, one disclosed in Japanese Patent Laid-Open No. 11-92279 is known. FIG. 3 schematically shows the structure thereof. This conventional diameter enlarging portion pulling mechanism includes a diameter enlarging portion support shaft 100a extending in the up-and-down direction in parallel with the crystal rotation axis O1 and in a horizontal direction at its lower end. It has an L-shaped structure in which the enlarged-diameter portion support 100b extending in the direction is integrally connected. The diameter-enlarging portion support shaft 100a is not coaxial with the crystal rotation axis O1, is rotatably supported about its longitudinal direction as an axis O2, and is vertically movable.
The diameter-enlarged portion support 100b is on standby from the crystal rotation axis O1 before the diameter-enlarged portion is locked, and the crystal rotation axis O1 is retained when the diameter-enlarged portion is locked.
Rotate to the position and lock the diameter expansion part and pull it up. O in O1 and O2 indicating the axis is overlined as shown in FIGS. 1 and 2, but is not shown in the specification because of restrictions.

[0004]

However, in the above-mentioned conventional example, the diameter enlarging portion support shaft 100a rotates about the axis O2 which is not coaxial with the crystal rotation axis O1 and extends in the horizontal direction, thereby extending in the horizontal direction. Has a structure in which it is supported by the diameter enlarging portion support shaft 100a by a so-called cantilever, so that the diameter enlarging portion support shaft 100a bends due to the weight of the crystal, and the diameter enlarging portion support body 100b inclines. Rotational axis O1 after supporting the enlarged portion 5b
Is the axis O1 '(crystal rotation axis) before supporting the enlarged diameter portion 5b.
Is different from the above, there is a problem that it hinders single crystallization.
In the worst case, the load cannot be supported, the neck portion is damaged, and the crystal falls.

In view of the above problems of the prior art, the present invention is capable of preventing a crystal from tilting in a structure in which a shaft for pulling up a diameter-enlarged portion is rotated around an axis that is not coaxial with a crystal rotation axis. The purpose is to provide a device.

[0006]

In order to achieve the above-mentioned object, the present invention is arranged so as to extend in the up-down direction so as to face the diameter-enlarging portion support shaft about the crystal rotation axis, and to arrange the diameter-enlarging portion support. And can be vertically moved up and down together with the diameter enlarging portion support shaft, and is provided in the vicinity of the other end of the diameter enlarging portion support.
A supplementary shaft for enlarging the diameter can be added so that the slit can be engaged.

That is, according to the present invention, in the single crystal pulling apparatus for pulling while supporting the enlarged diameter portion formed under the neck portion of the single crystal, the single crystal pulling apparatus can rotate about parallel axes that are not coaxial with the crystal rotation axis. And a diameter-enlarging portion support shaft that can be vertically moved up and down, one end of which is integrally rotatably connected to the lower end of the diameter-enlargement portion supporting shaft and can be vertically moved up and down. a case can be through-hole
A first slit having the same as the first slit
A larger diameter portion supports a second slit which is an opening formed in the direction, disposed extending in the vertical direction so as to face the larger diameter portion supporting the shaft about said crystal rotation shaft, the radial A diameter enlarging portion support auxiliary shaft that can move up and down together with the enlarging portion supporting member and the diameter enlarging portion supporting shaft and that can engage with the second slit provided at the other end of the diameter enlarging portion supporting member. And a diameter expanding portion
When the support shaft rotates in a predetermined direction, the first swing
The rit moves below the enlarged diameter portion, and at the same time, the second portion
Slit engages with the enlarged diameter portion supporting auxiliary shaft
A single crystal pulling device configured to move to a position is provided. Also according to the invention, under the neck of the single crystal
Single crystal pulling to support and pull up the enlarged diameter part formed on the
In the lifting device, parallel to the rotation axis of the crystal
Expandable diameter that can be rotated around the axis and can be moved up and down
Large support shaft and one end of the enlarged diameter support shaft
It is connected to the lower end of the
A through hole that can be engaged with the enlarged diameter portion is formed in the center.
The center of the crystal expansion axis and the expanded diameter support
Expand vertically to face the support shaft
The enlarged diameter portion support and the enlarged diameter portion are arranged to be long.
It can move up and down together with the support shaft and
A support member for supporting the enlarged diameter portion that can be engaged with the other end of the enlarged portion support member.
And a shaft, and at the other end of the diameter expansion part support,
Provided with a slit that the auxiliary shaft supporting the enlarged diameter part can engage
And in the vicinity of the lower end of the enlarged diameter support auxiliary shaft
Is provided with a stopper that receives the load of the support for the enlarged diameter portion.
An apparatus for pulling a single crystal is provided.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 is a block diagram showing a preferred embodiment of a single crystal pulling apparatus according to the present invention, and FIG.
FIG. 3 is a horizontal cross-sectional view showing in detail the diameter enlarged portion support body of FIG.

In FIG. 1, a seed crystal holder 2 is attached to the lower end of a pulling shaft 1 arranged in a chamber 18, and a seed crystal 3 is attached to the lower end of the seed crystal holder 2. The upper end of the lifting shaft 1 is the chamber 1
8 is arranged so as to project above, and the first structure 2
4, a motor 28 is attached so as to be rotatable around the crystal rotation axis O1. The first structure 24 is supported on the chamber 18 via the motor 20, the rod 22, and the screw portion 26. The rod 22 is formed with a screw to be screwed with the screw portion 26, and is rotated by the motor 20.
Therefore, when the motor 20 rotates, the first structure 24 moves up and down, and the lifting shaft 1 also moves up and down.

The diameter-enlarging portion support shaft 72 is arranged in parallel to a position that is not coaxial with the pull-up shaft 1, and the upper end of the diameter-enlarging portion support shaft 72 is set to the second structure 34B by the motor 40 with the longitudinal direction of the diameter-enlargement portion supporting shaft 72 as the axis O2. It is rotatably attached. Below the first structure 24, a rotating substrate 34A fixed to the pulling shaft 1 and rotating together.
Is provided. The second structure 34B has the same structure as the first structure 24 and is supported on the rotating substrate 34A via the motor 30, the rod 32, and the screw portion 36. Therefore, when the motor 30 rotates, the second structure 34B is formed. Since the body 34B moves up and down, the diameter expansion portion support shaft 72 also moves up and down.

Further, a diameter-enlarged portion supporting auxiliary shaft 80 is arranged vertically extending so as to face the diameter-enlarged portion supporting shaft 72 with the pull-up shaft 1 as a center, and its upper end is fixed to the second structure 34B. ing. Therefore, when the motor 30 rotates, the second structure 34 </ b> B moves up and down, so that the diameter expansion part support auxiliary shaft 80 moves up and down together with the diameter expansion part support shaft 72. In addition, the diameter expansion part support shaft 72 and the diameter expansion part support auxiliary shaft 80 are
It is movable in the vertical direction with respect to the rotary substrate 34A.

As shown in FIG.
The enlarged-diameter portion support body 70 shown in detail in FIG. FIG. 2 shows a horizontal cross section taken along the line BB ′ of FIG. 1, and a through hole 73 and a slit 74 for fitting and supporting the enlarged diameter portion are formed in the center thereof. One end of the enlarged diameter portion support body 70 is connected to the lower end of the enlarged diameter portion support shaft 72, so that the enlarged diameter portion support body 70 can rotate around the rotation axis O2 of the enlarged diameter portion support shaft 72. At the other end of the enlarged diameter portion support 70, the enlarged diameter portion supporting auxiliary shaft 8 is provided.
A slit 75 for supporting the enlarged diameter portion assisting shaft that engages with the lower end of 0 is formed. Further, a stopper 81 larger than the slit 75 for the diameter enlarging portion supporting auxiliary shaft is attached to the lower end of the diameter enlarging portion supporting auxiliary shaft 80, and when the lower end of the diameter enlarging portion supporting auxiliary shaft 80 and the slit 75 are engaged, The load of the enlarged diameter support 70 is applied to the stopper 81.
The diameter enlarging portion support body 70 is not tilted and the other end is not bent downward.

Further, as shown in FIG. 1, in the vertical middle of the enlarged diameter portion supporting shaft 72 and the enlarged diameter portion supporting auxiliary shaft 80, these shafts 72, 80 are the crystal rotation axis O1.
Are connected by a spread preventive 90 so that they do not spread outward in the radial direction. The spread prevention tool 90
In the vicinity of the left end in FIG. 1, while being fixed to the enlarged diameter portion supporting auxiliary shaft, for the enlarged diameter portion supporting shaft 72,
Even if the diameter enlarging portion support shaft 72 rotates around the rotation axis O2, it is rotatable so as not to rotate integrally. Further, the spread preventive tool 90 is slidable in the vertical direction and is not engaged with the pull-up shaft 1.

Next, the pulling operation will be described. By rotating the motor 20 in the descending direction to descend the first structure 24, that is, the pulling shaft 1, the polycrystalline melt 1 in which the seed crystal 3 is melted in the quartz crucible 10
Immerse in 1. Then, the motor 20 is rotated in the pulling direction and the motor 28 is rotated to rotate the pulling shaft 1 around the axis O1 to start the pulling. At this time, the enlarged diameter portion support 70 moves up and down integrally with the pull-up shaft 1, but is retracted to the outside of the axis O1. In the pulling step, the neck portion 4 is formed under the seed crystal 3, and then the diameter expansion portion 5a is formed under the neck portion 4,
A small diameter portion (constricted portion) 5b thicker than the neck portion 4 is formed below the enlarged diameter portion 5a, and a cylindrical body portion 7 is formed below the constricted portion 5b.

When a part of the body portion 7 is formed, the motor 30 is rotated so that the vertical position of the enlarged diameter portion support body 70 coincides with the constricted portion 5b, and then the enlarged diameter portion support body 7 is formed.
The motor 40 is rotated such that 0 engages with the constricted portion 5b to rotate the enlarged diameter portion support shaft 72 around the axis O2, and the motor 40 is stopped when the engagement is completed. At this time, the slit 75 for the enlarged diameter portion supporting auxiliary shaft of the enlarged diameter portion supporting body 70 engages with the lower end of the enlarged diameter portion supporting auxiliary shaft 80, and the tip of the enlarged diameter portion supporting body 70 is stopped by the stopper 8.
1 supported in the upward direction. After that, when the motor 30 is rotated in the pulling-up direction to complete the support of the enlarged diameter portion, the motor 20 is rotated in the pulling-up direction and the remaining body portion 7 is rotated.
To form.

It should be noted that the center of the through hole 73 of the enlarged diameter portion support 70 and the original center of the crystal rotation axis (the center of rotation of the mechanism for rotating the seed crystal) do not match due to the deformation and thermal expansion of the constituent members due to heat. For example, there is a deviation of about 0.1 mm. In order to prevent this, the enlarged diameter portion support 70 can have a double tray structure. That is, when the center of the through hole 73 is displaced from the center of the crystal rotation axis in the horizontal direction, the center of the through hole is placed on the expanded diameter portion support 70 (lower tray) by the horizontal load of the expanded diameter portion 5a. Is provided with a movable member (upper tray) which can be moved in the horizontal direction so as to coincide with the original crystal rotation axis.

[0017]

As described above, according to the present invention, in the structure in which the shaft for pulling up the diameter-enlarged portion rotates about an axis that is not coaxial with the crystal rotation axis, the diameter-enlarged portion support shaft is centered around the crystal rotation axis. Is arranged so as to extend in the up-down direction so as to be opposed to, and the diameter enlarging portion support and the diameter enlarging portion supporting shaft can be moved up and down in the up-down direction, and the other end of the diameter enlarging portion support can be engaged. Since the support auxiliary shaft is added, it is possible to prevent the crystal from tilting.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a single crystal pulling apparatus according to the present invention.

FIG. 2 is a horizontal cross-sectional view showing in detail the enlarged diameter portion support body of FIG.

FIG. 3 is a schematic configuration diagram showing a conventional single crystal pulling apparatus.

[Explanation of symbols]

72 diameter expansion part support shaft 73 Through hole 74 slits 80 Diameter Enlarged Area Support Auxiliary Shaft 81 stopper 90 Spread prevention tool

─────────────────────────────────────────────────── ─── Continued Front Page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C30B 15/30 H01L 21/208 C30B 29/06 502

Claims (3)

(57) [Claims] 1. A single crystal pulling apparatus for supporting and pulling a diameter-enlarged portion formed below a neck portion of a single crystal, wherein the single crystal pulling apparatus is rotatable about a parallel axis which is not coaxial with a crystal rotation axis and is vertically movable. A diameter-enlarging portion support shaft that can move up and down, and a through hole that is connected to the lower end of the diameter-enlarging portion supporting shaft so that it can rotate integrally and can move up and down in the vertical direction, and that can engage with the diameter-enlarging portion in the central portion. First slit having
And a second opening that opens in the same direction as the first slit.
A larger diameter portion supporting body, in which slits are formed, the arranged crystal rotation axis extends in the vertical direction so as to face the larger diameter portion support shaft as the center, said diameter enlarged portion support and the larger diameter Can be moved up and down together with the section support shaft and is installed at the other end of the enlarged diameter section support.
And a diameter-enlarged portion supporting auxiliary shaft engageable with the second slit, which is eclipsed, and the diameter-enlarged portion supporting shaft is rotated in a predetermined direction.
When, the first slit moves below the enlarged diameter portion
At the same time, the second slit assists the support of the enlarged diameter portion.
A single crystal pulling device configured to move to a position for engagement with a shaft . 2. A diameter expansion formed under a neck portion of a single crystal.
In a single crystal pulling device that supports and pulls the part, it is possible to rotate around parallel axes that are not coaxial with the crystal rotation axis.
And a diameter-enlarging portion support shaft that can be vertically moved up and down, and one end can rotate integrally with the lower end of the diameter-enlarging portion support shaft.
Connected vertically and vertically so that the
Expanded-diameter support with through holes that can engage with expanded-diameter parts
Body and the shaft for enlarging the diameter-enlarged portion around the crystal rotation axis
It is arranged so as to extend in the vertical direction so as to face
Up and down together with the expansion support and the diameter expansion support shaft
Can be moved up and down in the direction, and the other end of the enlarged diameter portion support is engaged.
A diameter-enlarging portion support auxiliary shaft that can be fitted, and a slit in which the diameter-enlarging portion supporting auxiliary shaft is engageable is provided at the other end of the diameter-enlarging portion supporting body, and the diameter-enlarging portion supporting auxiliary a stopper which receives the load of the larger diameter portion support that provided near the lower end of the shaft
Single crystal pulling device. 3. A spread prevention member for preventing the horizontal expansion of the diameter expansion part support shaft and the diameter expansion part support auxiliary shaft is provided, and the diameter expansion part support shaft and the diameter expansion part support assistance are provided by the expansion prevention member. The single crystal pulling apparatus according to claim 1 or 2 , wherein the single crystal pulling apparatus is connected.