JPH033638B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a semiconductor pulling machine using the CZ method,
In particular, the present invention relates to a device for preventing lateral vibration of a pulling shaft in which a flexible member such as a wire or a bead chain is used as the pulling shaft.

The semiconductor pulling machine needs to rotate the pulling shaft at a predetermined speed in order to fully satisfy the oxygen concentration and resistivity distribution characteristics of the pulled single crystal ingot. When a flexible member like the one described above is used for this pulling shaft, the rotation of the pulling shaft is affected by the natural frequency of the length of the pulling shaft, and resonance occurs within a certain rotational speed range, causing sideways movement. Because of the vibrations that occur, a device has been proposed in which a guide is provided to rotatably surround the pulling shaft in the middle to prevent lateral vibrations. However, even with such a guide, it is not possible to reliably prevent lateral vibration, probably because the resonance rotation speed changes when conditions such as pressure, temperature, and gas flow rate inside the pulling chamber change. Further, problems arose, such as the necessity of accurately aligning the guide with respect to the pulling shaft.

It is an object of the present invention to be able to rotate a pulling shaft made of a flexible member at a speed from around the resonance rotation speed to above the resonance speed without causing lateral vibration under any pulling conditions, and to prevent thermal deformation. To provide a device that can reliably prevent lateral vibration of a pulling shaft without using particularly advanced technology to support a guide for the pulling shaft, which is prone to misalignment.

To achieve this object, the present invention provides a semiconductor pulling machine that uses a flexible member as a pulling shaft, and is provided with a guide that rotatably surrounds the pulling shaft directly or indirectly. The shaft lateral vibration prevention device is characterized in that the guide is supported movably over a predetermined range along a plane perpendicular to the pulling shaft.

The following Figures 1 to 4 show one embodiment of the present invention.
The diagram will be explained. In FIG. 1, reference numeral 10 denotes the main body of the pulling machine, which has a hermetically sealed structure.The lower part forms a heating chamber 10a containing a crucible 11 and a heating device (not shown), and the upper part forms a heating chamber 10a containing a crucible 11 and a heating device (not shown).
A pulling chamber 10b for pulling up a single crystal ingot 13 from a melt 12 in the chamber 10 is formed.
A hoisting device 14 is attached to the upper part of the main body 10. The frame 15 of the hoisting device 14 is rotatably attached to the main body 10, and is rotated by a belt 18 from a hoisting shaft rotating motor 17 through a pulley 16 fixed to the lower part of the frame 15. . The frame 15 is provided with a hoisting drum 20 for hoisting a flexible hoisting shaft 19 such as a wire or a beat chain, and is rotated by a hoisting motor 21. A seed 22 is attached to the lower end of the pulling shaft 19.
A seed chuck 23 with a seed chuck attached thereto is attached, and the upper end side of the pulling shaft 19 has a hanging position determined by a fixed guide 24 provided on the frame 15.

A shaft 25 is installed in the lifting chamber 10b in parallel with the lifting shaft 19. This shaft 25 has
A pair of arms 26a, 26 as shown in FIG.
b is installed. The arms 26a and 26b are attached to the shaft 25 so as to be able to rotate with respect to each other, and are supported by a spring 27.
At this point, the protrusions 28a and 28b are brought into contact with each other. Also, these arm 2
6a and 26b are opened by links 31a and 31b respectively connected to rods 30 that are moved up and down by a drive unit 29 such as a cylinder.

When the arms 26a and 26b are closed as described above, they support the ring-shaped guide 32 engaged with the pulling shaft 19 at their tips, and when opened, they do not interfere with the single crystal ingot 13 being pulled up. It is made to be sufficiently far away from the pulling shaft 19 as shown in FIG.

As shown enlarged in FIGS. 3 and 4, the guide 32 has a collar 32a that is connected to the arm 26.
The peripheral surface of the body 32b, which is supported by the upper surfaces of the arms 26a and 26b and extends downward, is fitted into the opposing recesses 33a and 33b of the arms 26a and 26b with a gap S therebetween.

Next, the operation of this device will be explained. Prior to the start of lifting, the links 31a and 31b are actuated by the drive unit 29 and the rod 30 to move the arms 26a and 31b.
26b is opened and the pulling shaft 19 with the seed 22 attached
The guides 32, which have been previously engaged, are fitted into the recesses 33a, 33b of the arms 26a, 26b to close the arms 26a, 26b.

Next, the seeds 22 are added to the melt 12 in the crucible 11.
The frame 15 is rotated by the pulling shaft rotating motor 17, and the pulling shaft 19 is rotated to grow the single crystal ingot 13. At this time, the pulling shaft 19 is prevented from wobbling laterally by the guide 32 that is engaged in the middle.

Note that the resonant frequency f of the pulling shaft 19 is However, l in this equation (1) is not the actual length of the pulling shaft 19 from the guide 32, which is the fulcrum against lateral vibration, to the seed chuck 23, but the length of the pulling shaft 19 from the fulcrum to the seed chuck 23, the seed chuck 23,
2 and the center of gravity position G including the single crystal ingot 13. However, g in equation (1) is the gravitational acceleration.

Therefore, if there is no guide 32 as described above and the pulling shaft 19 is simply held by the fixed guide 24 at the upper end, the length l is the longest at the start of pulling and gradually becomes shorter as the pulling progresses. Therefore, the allowable rotation speed of the pulling shaft 19 determined in relation to the resonance frequency f is kept low, but by providing the guide 32, it is possible to shorten l and increase the allowable rotation speed. can.

However, when the guide 32 is
a, 26b, the pulling shaft 1
9 needs to be rotated within the guide 32,
Perhaps because there is a slight gap between these,
Equation (1) does not apply completely, and the heating chamber 10a
If the ambient conditions such as the pressure and temperature inside the pulling chamber 10b and the flow rate of an inert gas (not shown) flowing into the chamber 10b change, lateral vibration occurs and the intended purpose cannot be fully achieved.

However, in this device, a gap S is provided between the guide 32 and the arms 26a, 26b as shown in FIG.
If it is mounted so that it can move along the upper surface of the drawing shaft 19 in a plane perpendicular to the pulling shaft 19, lateral vibration will not occur. According to experiments, the size of the gap S is such that even if the shaft 25 and the arms 26a, 26b change due to assembly errors or thermal deformation during operation, the guide 32 remains perpendicular to the fixed guide 24 above. Slightly larger than the value that can be used, usually guide 32
It suffices if it is possible to move about 1 mm within the recesses 33a and 33b. guide 32 and arm 26a,
26b, it is preferable to create a slight frictional force between the two and a slight damping effect by considering the materials of the two and the surface condition of the contact surfaces.

As the pulling progresses, the seed chuck 23 moves to the guide 32.
When the robot approaches the arm 26, the drive unit 29 is activated and the rod 30 and links 31a and 31b move the arm 26.
Single crystal ingot 13 pulled from a and 26b
Open until it does not interfere with the At this time, the guide 32 falls onto the seed chuck 23 and is supported. Thereafter, the fulcrum of the pulling shaft 19 is determined by the upper fixed guide 24, but since the length of the hanging shaft 19 at this time is about half of the initial length, The allowable rotation speed is relatively high.

Although this embodiment shows an example in which only one guide 32 is provided, a plurality of guides 32 are provided along the pulling shaft 19, and as the pulling progresses, the arms 26a, 26
The permissible rotational speed can be further increased by sequentially opening the guide 32 or by gradually raising the guide 32 along the shaft 25 as the pulling progresses. Further, the opening and closing of the arms 26a, 26b is not limited to the links 31a, 31b;
It goes without saying that various methods can be adopted, such as a method using a cam plate inserted between 26b.

As described above, according to the present invention, it is possible to more reliably suppress the lateral vibration caused by resonance of the pulling shaft made of a flexible material, and the guide can move along a plane perpendicular to the pulling shaft. Because of this structure, it is advantageous that there is no need to use special techniques for the structure or assembly of members such as arms that support it.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway schematic diagram showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, Fig. 3 is an enlarged view of section A in Fig. 2, and Fig. 4 is a cross-sectional view taken along the - line in Fig. 1. FIG. 3 is a sectional view taken along the - line in FIG. 3; 10... Main body of the pulling machine, 11... Crucible, 13...
...Single crystal ingot, 14...Hoisting device, 19...
...Lifting shaft, 25... Axis, 26a, 26b... Arm, 29... Drive section, 31a, 31b... Link, 32... Guide.

Claims (1)

[Scope of Claims] 1. A device for preventing lateral vibration of a pulling shaft of a semiconductor pulling machine using a flexible member as a pulling shaft, which is provided with a guide that rotatably surrounds the midway of the pulling shaft, directly or indirectly. 1. A pulling shaft lateral vibration prevention device for a semiconductor pulling machine, characterized in that the guide is movably supported over a predetermined range along a plane perpendicular to the pulling shaft. 2. A pulling shaft lateral vibration prevention device in a semiconductor pulling machine according to claim 1, wherein the guide is provided movably along the pulling shaft. 3. A pulling shaft lateral vibration prevention device in a semiconductor pulling machine according to claim 1, wherein a plurality of guides are detachably attached along the pulling shaft. 4. A pulling shaft lateral vibration prevention device in a semiconductor pulling machine according to claim 1, 2 or 3, wherein the member supporting the guide is formed to be openable and closable symmetrically with respect to the pulling shaft. 5. A patent claim in which the guide is supported so as to have a dipping effect due to frictional force against movement in the direction along the plane between the guide and a member that supports the guide so as to be movable along the plane perpendicular to the pulling axis. A pulling shaft lateral vibration prevention device in a semiconductor pulling machine according to item 1, 2, 3 or 4.