JPH0232689Y2 - - Google Patents

Description

[Detailed description of the invention] (Technical field to which the invention pertains) The invention is directed to an apparatus for manufacturing single crystals such as _Si by the CZ method, specifically a device for preventing rotational vibration of a pulling shaft of a single crystal pulling apparatus. It is about improvement.

(Conventional Device) In a conventional single crystal pulling device, a flexible material such as a wire or chain is used for the seed pulling shaft, which allows the seed crystal to move vertically while rotating. In some cases, a method is used to suppress the height of the device, but in such a device, it may be difficult to produce a perfect single crystal due to seed rotational vibration due to seed rotation or external vibration.

To solve this problem, there is a rotational shake prevention device that uses friction, proposed by the present inventor. FIG. 3 is a structural example diagram of a single crystal pulling device showing an example of using this device. In the figure, 21 is a furnace body, 22 is a seed, 23 is a single crystal, 24 is a crucible, 25 is a pulling shaft, 26 is a support stand, 27 is a guide, and 28 is a friction plate. However, in order to effectively utilize the effect of the rotational shake prevention device 26 to 28, it is important to select the mounting position in the vertical direction with respect to the pulling shaft 25. Generally, it is advantageous to select a mounting position as close to the lower end of the pulling shaft as possible. be. According to experiments, it was effective when installed approximately 400 mm or more below the upper end of the pulling shaft. The disadvantages of such a rotational shake prevention device are: 1. The total height of the lifting device must be higher than when no prevention device is used due to the dimension from the upper end of the pulling shaft to the installation position of the rotational shake prevention device. cause This goes against the purpose of using a flexible material for the pulling shaft and has no effect.

2 In order to make the overall height of the pulling device the same as that of conventional devices, it is necessary to provide a mechanism to move the rotational shake prevention device up and down independently in accordance with the vertical movement of the pulling shaft. There are disadvantages in that the structure of the upper apparatus becomes complicated and the possibility of contaminating the atmosphere inside the pulling furnace increases.

(Specific purpose of the invention) This invention aims to immediately attenuate rotational vibration when a flexible material is used for the pulling shaft of an apparatus for producing single crystals by the CZ method. The preventer can be installed without disadvantages such as an increase in the overall height of the single crystal pulling device and a reduction in the stroke of the pulling axis movement, or without adding a mechanism to move the preventer up and down. It is intended to make it possible.

(Structure and operation of the invention) Figures 1 and 2 are diagrams showing an example of the configuration of a single crystal pulling apparatus in which the invention is implemented. The status at the end of each is shown. In these figures, 1 is the upper chamber of the pulling device, 2 is the seed chuck, 3 is the crystal being pulled, 4 is the crucible, 5 is the pulling shaft, 6 is the pulling shaft support, 7 is the movable friction plate, 8 is a fixed friction plate,
Reference numeral 9 is a mechanism for vertically moving and rotating the pulling shaft 5, and includes a driving source.

The main part of the present invention is a rotational shake prevention device in a mechanism for rotating a single crystal growing in a furnace of a single crystal pulling apparatus at a low speed and pulling it up while preventing rotational shake. It is composed of an upper shaft support 6, a movable friction plate 7, and a fixed friction plate 8. Among these, the pulling shaft support 6 is configured so that the pulling shaft passes through the center of the pulling shaft 5 and can freely move up and down along the pulling shaft. It has a structure that can be pushed by the seed chuck as it rises and rise together in the upper chamber 1, and when rotational vibration occurs in the pulling shaft 5, the horizontal movement is transmitted to the movable friction plate 7. The movable friction plate 7 has a hole for supporting the pulling shaft support 6 so that it does not fall. The diameter of this hole is
be large enough to pass through. The movable friction plate 7 slides on the upper surface of the fixed friction plate 8 in synchronization with the horizontal movement of the pulling shaft 5. The fixed friction plate 8 is a flat plate that supports the movable friction plate 7, and has a hole in the center through which the seed chuck 2 can pass. The optimum position for fixing the fixed friction plate 8 is determined depending on the length of the pulling shaft, but generally it is located at the upper chamber 1.
It is often provided near the upper end of the The pulling shaft support 6 and the movable friction plate 7 may be fixed together, and this integral structure is fixed to the pulling shaft 5 so that it can move freely in the vertical direction, and the seed chuck 2 can rise in the upper chamber 1 together with the seed chuck. Since the movable friction plate 7 is always located above the fixed friction plate 8, the selection of the fixed position of the plate 8 is important, but if rotational runout occurs in the pulling shaft 5, it should be synchronized (followed) with its horizontal movement. and slide on the surface of the fixed friction plate 8.

Next, the rotational shake prevention operation will be explained.

(1) The state during crystal pulling is as shown in Fig. 1, and the upper end of the seed chuck 2 is below the rotational vibration prevention device. When rotational runout occurs in the pulling shaft 5, the moving friction plate 7 closely follows the movement on the horizontal plane.
slides on the fixed friction plate 8, and the rotational runout is immediately attenuated by the friction between the two.

(2) The state at the end of crystal pulling is as shown in FIG. 2, for example, where the seed chuck 2 rises to the top of the vertical movement stroke and the pulled crystal 3 is stored in the upper chamber 1. At this time, the pulling shaft support 6 (or the pulling shaft support 6 and the movable friction plate 7) rises by being pushed up by the upper end of the seed chuck.
(or seed chuck 2 and crystal 3) passes through the central hole of moving friction plate 7 (or fixed friction plate 8).

(Effects of the invention) By implementing the invention, it becomes easy to rapidly damp the rotational vibration that occurs in a single crystal pulling apparatus using a flexible material such as a wire or chain for the crystal pulling shaft, and the pulling This has a significant effect on improving the quality of single crystals.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams showing an example of the configuration of a single crystal pulling apparatus embodying the present invention, with FIG. 1 showing a state in which the single crystal is being pulled, and FIG. 2 showing the state in which the single crystal has been pulled. FIG. 3 is a diagram showing an example of the configuration of a conventional single crystal pulling apparatus provided with a rotational steady rest. 1... Upper chamber, 2... Seed chuck,
3, 23... Crystal being pulled, 4, 24... Crucible, 5, 25... Pulling shaft, 6... Pulling shaft support,
7...Moving friction plate, 8...Fixed friction plate, 9,29
... Pulling mechanism, 21 ... Furnace body, 22 ... Seed,
26...Support stand, 27...Guide, 28...Friction plate.

Claims (1)

[Scope of utility model registration request] A device for preventing rotational vibration of the pulling shaft installed in the furnace of a single crystal pulling apparatus using a flexible material such as a wire or chain for the pulling shaft is passed through the pulling shaft to prevent the seed chuck at the tip of the single crystal. a lifting shaft support that can be freely moved up and down along the lifting shaft using the lift;
The supporting tool is fitted into a hole provided at the center and is large enough to allow the seed chuck to pass through, and is held, and is movable in the horizontal direction following the rotational vibration of the pulling shaft that occurs when pulling a single crystal. A movable friction plate is fixed at an optimal position above the furnace and has a hole in the center through which the seed chuck and the pulled single crystal can pass, and the movable friction plate is seated on the upper surface. 1. A single-crystal pulling device comprising a fixed friction plate that provides frictional resistance when the device moves horizontally with the rotational deflection of a pulling shaft.