JP2001261486A - Device for pulling up single crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To coincide the rotation axis of a crystal when a diameter-enlarged part is pulled up with the rotation axis of the crystal when a neck part is pulled up a simple structure. SOLUTION: A member 10 for suspending a supporting member for supporting a diameter-enlarged part 2 has a crystal-holding tray 11 and a member 12 contacting with a crystal, and a recessed part for mounting the member 12 contacting with the crystal is formed on the upper surface of the crystal-holding tray 11 and the width of the recessed part is formed so that the member 12 contacting with the crystal can freely move in the horizontal direction of the sliding surface 13. When the center of supporting members for supporting the diameter-enlarged part 2 do not coincide with the rotation axis 01 of the crystal and rotate around the rotation axis 01, the member 12 contacting with the crystal is pushed by the load in the horizontal direction of the diameter-enlarged part 2 and moved in the horizontal direction so that the rotation axis 01 coincides, and thereby even when the center of the crystal holding tray 11 rotates round the rotation axis 02 of the crystal, the rotation axis 01 of the crystal does not deviate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 In general, 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 large-weight single crystal (a body portion) directly under the neck portion is known. In addition, there is a possibility that the neck portion may not be able to withstand a heavy load and break. Therefore, as a method of preventing this, an enlarged diameter portion is formed below the neck portion, and a smaller diameter portion (constriction portion) larger than the neck portion is formed below the enlarged diameter portion. By being supported by the support member,
A method has been proposed in which a load is gradually shifted from supporting the neck portion to supporting the enlarged-diameter portion while the single crystal is being pulled at a predetermined speed, and is completely shifted to supporting the enlarged-diameter portion.

As a mechanism for realizing this method, for example, Japanese Patent Application Laid-Open Nos. Hei 10-279386 and Hei 11-922
As disclosed in Japanese Patent Application Publication No. 79 (all publications related to the prior application of the present applicant) and the like, in addition to the neck (seed crystal) pulling-up mechanism, the upper end is rotated coaxially with the neck so as to extend vertically. A diameter-enlarging portion supporting shaft is provided, and a diameter-enlarging portion is formed by using a tray-shaped locking member or supporting member having a through hole at the lower end of the diameter-enlarging portion supporting shaft at which the diameter-enlarging portion can be locked. There has been known a method of stably supporting from below.

[0004]

However, in the above-described conventional enlarged diameter portion support mechanism, even if the upper end of the enlarged diameter portion support shaft rotates coaxially with the neck portion, the lower end of the enlarged diameter portion support shaft remains coaxial. And if it is shifted horizontally,
The locking member does not rotate around the center of the through-hole, and the center of the through-hole rotates around the axis of the enlarged-diameter support shaft. In addition, there is a problem that the crystal is vibrated in the horizontal direction or the like to impair single crystallization. In order to prevent this, adjustment is performed in advance so that the lower end of the enlarged diameter portion support shaft is coaxial with the upper end in a state where the inside of the chamber is not yet heated. In the state where the inside is heated and actually pulled up, the center of the through hole of the locking member is aligned with the original crystal rotation axis center (the rotation center of the mechanism for rotating the seed crystal) due to the deformation and thermal expansion of the constituent members due to heat. They do not coincide with each other and, for example, deviate by about 0.1 mm.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a single crystal pulling apparatus which has a simple structure and can match the crystal rotation axes at the time of pulling up a neck portion and at the time of pulling up an enlarged diameter portion. I do.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a tray at the lower end of an enlarged diameter support shaft whose upper end rotates coaxially with a neck portion, and further, the center of the tray has an enlarged diameter portion. If the rotation axis of the support shaft (original crystal rotation axis) is displaced in the horizontal direction, the center of the through hole is horizontally aligned with the original crystal rotation axis by the horizontal load of the enlarged diameter portion on the tray. A movable member movable in the direction is provided.

That is, according to the present invention, a neck support member that pulls up while rotating a neck portion of a single crystal, and a diameter-enlarged portion support shaft that is arranged so as to extend in the vertical direction and whose upper end rotates coaxially with the neck portion. A tray attached to the lower end of the enlarged-diameter support shaft and having at its center a first through-hole having an inner diameter larger than the outer diameter of the enlarged-diameter portion formed below the neck portion; A second through-hole in which the enlarged-diameter portion can be locked is formed, and when the center of the tray is horizontally displaced from the rotation axis of the enlarged-diameter support shaft, the enlarged-diameter portion is provided on the tray. And a movable member movable in the horizontal direction so that the center of the second through hole coincides with the rotation axis of the enlarged diameter portion by the horizontal load.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram schematically showing a preferred embodiment of a single crystal pulling apparatus according to the present invention, FIG. 2 is a plan view and a cross-sectional view showing the enlarged diameter portion support member of FIG. 1 in detail, and FIGS. FIG. 3 is an explanatory diagram illustrating an operation of a diameter-enlarged-section support member in FIG.

In FIG. 1, although not shown, the upper end of the neck portion 1 is formed in connection with a seed crystal. Also,
The seed crystal is supported by a seed crystal holder, the seed crystal holder is supported by a wire or a shaft, and the wire and the shaft can be moved up and down in a vertical direction (a crystal rotation axis O1).
Can be rotated around. In FIG. 1, an enlarged diameter portion 2 is formed below a neck portion 1, a small diameter portion (constriction portion) 3 is formed below the enlarged diameter portion 2, and a cylindrical body portion 4 is formed below the constricted portion 3. This shows a state where the parts are formed and the rotation axes of the parts 1 to 4 of the crystal are shifted as described in the conventional example. In addition,
FIG. 1 is a side view of FIG. 2A viewed from the right.

At the time when a part of the body portion 4 is formed, the diameter-enlarged portion support member 11, which has retreated from the crystal rotation axis O1,
Reference numeral 12 denotes a slit 11- of the enlarged diameter portion support members 11, 12.
1 is horizontally moved in the direction of the crystal rotation axis O <b> 1 so as not to touch the constricted portion, so that it is inserted below the enlarged diameter portion 2. Thereafter, the enlarged diameter portion support members 11 and 12 are pulled up, and the enlarged diameter portion 2 is supported. Diameter enlarged part support member 1
Numerals 1 and 12 are connected to the lower end of a diameter-enlarged portion support member suspending member 10 which is arranged to extend in the vertical direction. The upper end thereof is rotatable around a crystal rotation axis O1. Therefore, since the enlarged diameter portion supporting members 11 and 12 are only supported by the lower end of the enlarged diameter portion supporting member hanging member 10, if the center O2 is displaced from the crystal rotation axis O1, the actual state is maintained as it is. The crystal rotation axis deviates from the original rotation axis O1 to the center O2 of the enlarged diameter portion support member 11.

In order to prevent this, the enlarged diameter portion support members 11 and 12 are configured as shown in FIGS. 2A is a plan view, and FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A. The enlarged diameter portion supporting members 11 and 12 have a crystal holding tray 11 and a crystal contact member 12, and a concave portion for mounting the crystal contact member 12 is formed on the upper surface of the crystal holding tray 11, and the size of the concave portion is The crystal contact member 12 is configured to be movable on the sliding surface 13 in the horizontal direction.

The constriction 3 is formed in the crystal holding tray 11 and the crystal contact member 12 when the enlarged-diameter support members 11, 12 retracted from the crystal rotation axis O1 move horizontally in the direction of the crystal rotation axis O1. Slits 11-1 and 12-1 are respectively formed so as to enter the centers thereof, and circular through holes 11-2 and 12-2 for supporting the enlarged diameter portion are formed at the centers.
Are formed. Through-hole 12-2 of crystal contact member 12
Is designed to be larger than the constricted portion 3 and smaller than the enlarged-diameter portion 2, so that it is formed so as to engage with a lower portion of the enlarged-diameter portion 2. The through hole 11-2 of the crystal holding tray 11 is formed larger than the through hole 12-2 of the crystal contact member 12, that is, larger than the diameter of the constriction 3.

Next, with reference to FIG.
The operations 1 and 12 will be described in detail. First, after the seed crystal (not shown) is lowered until it is immersed in the melt 5 of the polycrystal, the seed crystal is pulled up while being rotated. Here, by controlling the pulling speed as shown in FIG. 1, the neck portion 1 is formed below the seed crystal, and the neck portion 1 is formed.
The enlarged diameter part 2 is formed under the diameter, the constricted part 3 is formed below the enlarged diameter part 2, and the cylindrical body part 4 is formed below the constricted part 3.
Is formed. When a part of the body part 4 is formed, FIG.
As shown in (a), the enlarged-diameter portion supporting members 11 and 12 are positioned below the enlarged-diameter portion 2 so as not to contact the constricted portion 3.
It is moved in the horizontal direction so as to be the center of the through holes 11-2 and 12-2 via 1-1 and 12-1.

Next, when the enlarged diameter support members 11 and 12 rise while rotating together with the seed crystal, and ascend until the crystal contact member 12 comes into contact with the enlarged diameter portion 2, the center O2 of the enlarged diameter support members 11 and 12 is raised. Is not coincident with the crystal rotation axis O1 and is rotating around the center O2, the center of the through hole of the crystal contact member 12 is caused by the horizontal load of the enlarged diameter portion 2 as shown in FIG. Are pushed in the horizontal direction so as to coincide with the rotation axis O1 and move.

FIG. 4 shows the operation in more detail. FIG. 4A shows an ideal positional relationship, in which the center O2 of the enlarged diameter portion support members 11, 12 coincides with the crystal rotation axis O1. FIG. 4B shows a state before the center of the enlarged diameter portion is locked when the center O2 of the enlarged diameter portion support members 11 and 12 does not coincide with the crystal rotation axis O1 and rotates around the center O2. FIG.
As shown in (b), the enlarged diameter portion support members 11 and 12 are rotating around their center O2 (offset from the crystal rotation axis O1). FIG. 4C shows a state after the enlarged diameter portion is locked, and the center of the through hole of the crystal contact member 12 is pushed in the horizontal direction by the horizontal load of the enlarged diameter portion 2 so as to coincide with the rotation axis O1. When moved, the crystal rotation axis O1 does not shift even if the center of the crystal holding tray 11 rotates around the crystal rotation axis O1.

Therefore, since the crystal contact member 12 performs self-alignment, the crystal rotation axes at the time of pulling up the neck portion and at the time of pulling up the enlarged diameter portion can be matched with a simple structure. Then, the state gradually shifts from the neck portion support to the enlarged diameter portion support in a state where the crystal rotation axes are coincident, and when the load movement is completed, the support is pulled up only by the neck portion support.

Furthermore, in order to prevent the rotation axis O1 of the single crystal from moving when the crystal contact member 12 is pushed in the horizontal direction by the enlarged diameter portion 2, the crystal contact member 12 should be made as light as possible. Desirably, for example, the contact surface between the crystal holding tray 11 and the crystal contact member 12, ie, the sliding surface 1
3 is made smooth like a mirror finish, the weight of the seed crystal supported by the shaft is about 1/100 or less of the load when the enlarged diameter portion is locked, and about 1/100 in the case of the wire type.
/ 200 or less is desirable.

The through-hole 12-2 of the crystal contact member 12
That the upper surface side is formed in a tapered shape is a preferable aspect from the viewpoint of stably supporting the enlarged diameter portion 2.
Further, the fact that the surface where the crystal holding tray 11 and the crystal contact member 12 are in contact with each other, that is, the sliding surface 13 is mirror-finished is a preferable embodiment from the viewpoint that the latter can freely move horizontally on the former. .

Further, the crystal contact member 12 which is a movable member
In order to prevent the crystal from coming off the crystal holding tray 11 when it is engaged with the enlarged diameter portion 2, it comes into contact with the upper surface of the crystal contact member 12 as shown in FIGS. It is a preferred embodiment that the locking member 14 arranged in a proper state is attached to the crystal holding tray 11. Further, if the planar shape of the crystal contact member 12 is circular, there is a possibility that the single crystal will rotate. Therefore, this can be prevented by making it polygonal (square in the embodiment of FIG. 2). . Further, the planar shape of the slit 12-1 of the crystal contact member 12 is such that the constriction 3 normally penetrates along the slit 12-1 even if the crystal contact member 12 and the radially enlarged portion 2 are displaced in the circumferential direction. For example, as shown in FIG. 5, it is preferable that the outer side in the radial direction is formed wider than the inner side toward the hole 12-2.

[0020]

As described above, according to the present invention, a tray is provided at the lower end of the enlarged diameter portion support shaft whose upper end rotates coaxially with the neck portion, and the center of the tray is rotated by the enlarged diameter portion support shaft. If the axis is offset horizontally,
A movable member is provided on the tray that can move in the horizontal direction so that the center of the through-hole coincides with the rotation axis of the enlarged diameter portion due to the horizontal load of the enlarged diameter portion. The crystal rotation axis when pulling up the enlarged diameter portion can be matched.

[Brief description of the drawings]

FIG. 1 is a side view showing a preferred embodiment of a single crystal pulling apparatus according to the present invention.

FIGS. 2A and 2B are a plan view and a cross-sectional view illustrating the enlarged diameter portion support member of FIG. 1 in detail.

FIG. 3 is an explanatory view showing an operation of a diameter-enlarged portion support member of FIG. 2;

FIG. 4 is an explanatory view showing an operation of a diameter-enlarged portion support member of FIG. 2;

FIG. 5 is a configuration diagram illustrating a modified example of a diameter-enlarged portion support member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Diameter enlarged part support member suspension member 11 Crystal holding tray (constituting diameter enlarged part support member with crystal contact member) 11-1, 12-1 Slit 11-2, 12-2 Through hole 12 Crystal contact member (movable 13) Sliding surface 14 Locking member

Claims (5)

[Claims] 1. A neck support member that pulls up while rotating a neck portion of a single crystal, a diameter-enlargement portion support shaft that is arranged so as to extend in a vertical direction, and whose upper end rotates coaxially with the neck portion; A tray provided with a first through hole having an inner diameter larger than the outer diameter of the enlarged diameter portion formed below the neck portion at the center of the tray; A second through hole that can be locked is formed, and when the center of the tray is horizontally displaced from the rotation axis of the enlarged diameter portion support shaft, a horizontal load of the enlarged diameter portion on the tray is provided. The second
And a movable member that is movable in the horizontal direction so that the center of the through-hole coincides with the rotation axis of the enlarged diameter portion. 2. The single crystal pulling apparatus according to claim 1, wherein the weight of the movable member is about 1/100 or less of the load when the enlarged diameter portion is locked. 3. The single crystal pulling apparatus according to claim 1, wherein an upper surface of the second through hole of the movable member is formed in a tapered shape. 4. The single crystal pulling apparatus according to claim 1, wherein a surface of the tray and the movable member that come into contact with each other has a mirror finish. 5. In order to prevent the movable member from coming off the tray, it is preferable that a locking member arranged in contact with or in a contactable state with the upper surface of the movable member is attached to the tray. The single crystal pulling apparatus according to any one of claims 1 to 4, characterized in that: