JP7013984B2 - FZ furnace polycrystalline raw material gripper - Google Patents

Description

The present invention relates to a polycrystalline raw material gripper for an FZ (Floating Zone) furnace.

Conventionally, when a silicon single crystal is produced by the FZ (Floating Zone) method, the silicon polycrystalline raw material is held by a silicon polycrystalline raw material gripper, and a seed crystal holder and a high frequency induction heating coil arranged at the lower part in the chamber are used. It is used to melt a polycrystalline raw material of silicon to produce a silicon single crystal ingot. Here, when the silicon polycrystalline raw material is melted by the high-frequency induction heating coil, the silicon polycrystal raw material is melted while being held by the polycrystalline raw material gripper.

For example, Patent Document 1 includes a cylindrical internal adapter that opens downward and an external adapter provided on the outer surface side thereof, and presses and narrows the outer peripheral wall of the external adapter to the outer peripheral portion of the silicon polycrystalline raw material. A polycrystalline raw material holder provided with an arm is disclosed.
Further, Patent Document 2 is provided with a cylindrical adapter that opens downward, and an eccentric piece that gradually increases the radius of gyration when rotated downward is provided at the lower end of the adapter, and the eccentric piece is gradually tightened by screwing from above. A polycrystalline raw material holder for holding a silicon polycrystalline raw material by increasing the radius of gyration of the silicon is disclosed.

Japanese Unexamined Patent Publication No. 5-148701 Japanese Patent Application Laid-Open No. 5-246792

The techniques described in Patent Document 1 and Patent Document 2 have a structure in which a stainless steel holding arm or an eccentric piece abuts on the outer peripheral side surface of a silicon polycrystal and is sandwiched. Since the coefficient of thermal expansion of the silicon polycrystalline raw material is higher than that of the stainless steel material, the raw material of the silicon polycrystalline material becomes shorter, and when the influence of the radiant heat applied to the holder becomes large, the gripping force due to the displacement of the eccentric top and the arm part becomes large. There are problems such as loosening, galling due to seizure of the pressing bolt of the arm part and the holding screw of the eccentric piece.
In addition, since there is a cylindrical opening in the center, there is also a problem that heat affects the upper rotation shaft to be coupled.
Due to the above problems, there has been a problem that the deviation (center runout) of the center of the rotation axis increases as the crystal growth progresses.

An object of the present invention is to provide a polycrystalline raw material gripping tool for an FZ furnace in which a silicon single crystal is not easily affected by heat even when the silicon polycrystalline raw material is heated and the increase in runout due to crystal growth is small in the production of a silicon single crystal by the FZ method. To provide.

The polycrystalline raw material gripping tool of the FZ furnace of the present invention is a polycrystalline raw material gripping tool of the FZ furnace that grips the polycrystalline raw material of the FZ (Floating Zone) furnace, and supports the load of the silicon polycrystalline raw material. A chuck portion through which a shaft and a plurality of locking portions for locking the silicon polycrystalline raw material are inserted, a horizontal position adjusting portion for adjusting the position of the plurality of locking portions in the horizontal direction, and the plurality of locking portions. Further, it is characterized in that it is arranged with a gap provided between the horizontal position adjusting portions and is provided with a shielding portion that shields radiant heat from the silicon polycrystalline raw material.

According to the present invention, since the polycrystalline raw material gripper is provided with a shielding portion, the silicon polycrystalline raw material is heated by the high frequency induction heating coil, and the chuck portion is displaced due to thermal strain due to the influence of the generated radiant heat. However, it is possible to prevent the gripping bolt from being displaced following it. Further, it is possible to suppress the influence of heat due to the heating of the silicon polycrystalline raw material from being transferred to the horizontal position adjusting section, and to suppress the change in the adjusted state of the horizontal position adjusting section.

In the present invention, the horizontal position adjusting portion is provided so as to surround the support shaft, and is screwed into each of the position adjusting portion main body in which a plurality of female screw holes are formed around the support shaft and the female screw holes. It is preferable that the bolts are provided with a plurality of bolts whose tips are in contact with the support shaft, and the female screw holes facing each other and the screw pitches of the bolts are different.
According to the present invention, by changing the screwing amount of the bolt screwed into the female screw hole of the position adjusting portion main body, the pushing amount to the support shaft is changed, and the gripping position of the silicon polycrystalline raw material with respect to the support shaft. Can be changed. Moreover, since the amount of bolts pushed in can be finely adjusted by changing the female screw holes facing each other and the screw pitch of the bolts, the gripping position of the silicon polycrystalline raw material with respect to the support shaft can be adjusted with high accuracy. can.

In the present invention, the plurality of female screw holes are formed in pairs in a direction orthogonal to each other, and in the pair of female screw holes orthogonal to each other, one screw pitch is smaller than the other screw pitch, and the pair of female screw holes are formed. It is preferable to adjust the screwing position of the bolt to be screwed into.
According to the present invention, a pair of female screw holes are formed in a direction orthogonal to each other. Therefore, by adjusting the screwing position of the bolt inserted into each female screw hole, the axis of the silicon polycrystalline raw material can be formed. It can be aligned with the center of the FZ furnace. In particular, since one screw pitch is smaller than the other screw pitch, it is possible to adjust the approximate position with bolts with a large pitch and fine adjustment with bolts with a small pitch, so positioning with high accuracy is possible. Can be done. Therefore, by positioning the silicon polycrystal raw material with high accuracy, it is possible to prevent the silicon polycrystal from drawing a circular orbit with a predetermined diameter during the growth of the silicon single crystal.

In the present invention, the chuck portion is composed of an upper plate and a lower plate, and a plurality of elongated holes extending from the outer periphery toward the radial center are formed in the upper plate and the lower plate, respectively, through the plurality of elongated holes. It is preferable that the plurality of locking portions are inserted.
According to the present invention, since the locking portion is inserted into each of the long hole of the upper plate and the long hole of the lower plate, the radial position of the locking portion and the radial position of the locking portion can be obtained by relatively rotating the upper plate and the lower plate. The circumferential position can be changed.

In the present invention, the heat shield is preferably made of a stainless steel plate having a thickness of 0.8 mm or more.
According to the present invention, since the shielding portion is made of a stainless steel plate having a thickness of 0.8 mm or more, the gap between the position adjusting portion main body and the locking portion can be reduced. Therefore, the heat shielding effect can be ensured in a narrow gap, and the deformation of the horizontal position adjusting portion can be suppressed.

The schematic diagram which shows the structure of the FZ furnace which concerns on embodiment of this invention. The plan view and the side view which show the structure of the polycrystalline raw material gripping tool in the said Embodiment. A plan view and a cross-sectional view showing the structure of the polycrystalline raw material gripper according to the embodiment. The plan view which shows the structure of the heat shield plate in the said Embodiment. The plan view and the sectional view which show the structure of the horizontal position adjustment part in the said Embodiment. The side view which shows the structure of the polycrystalline raw material gripping tool in the comparative example. The graph which shows the measurement result of the comparative example. The graph which shows the measurement result of an Example.

[1] Overall Configuration of FZ Reactor 1 FIG. 1 shows a schematic diagram of the FZ Reactor 1 according to the embodiment of the present invention. This FZ furnace 1 is an apparatus for growing a silicon single crystal 3 from a silicon polycrystalline raw material 2 by an FZ (Floating Zone) method. The FZ furnace 1 includes a crystal holder 4, a high-frequency induction heating coil 5, a heat insulating cylinder 6, a product single crystal weight holder 8, and a polycrystalline raw material gripping tool 9.

The crystal holder 4 is a member that holds the tip portion of the silicon single crystal 3, and the seed crystal is fixed on the upper portion, and the seed crystal is pulled downward as the silicon single crystal 3 grows. The product single crystal weight holder 8 abuts on the shoulder portion of the silicon single crystal 3 and holds the weight of the silicon single crystal 3.
The polycrystalline raw material gripping tool 9, which will be described in detail later, chucks the upper end of the silicon polycrystal raw material 2.

The high-frequency induction heating coil 5 is composed of a ring-shaped body and is not shown, but is connected to a high-frequency power source and melts the silicon polycrystalline raw material 2 by high-frequency induction heating to form a silicon melting zone 3A.
The heat insulating cylinder 6 is composed of a ring-shaped body surrounding the grown silicon single crystal 3. The heat insulating cylinder 6 controls the temperature of the silicon single crystal 3 in the process of solidifying the melting zone 3A.

In such an FZ furnace 1, the upper end of the polycrystalline raw material 2 is held by the polycrystalline raw material gripper 9, and the lower end of the silicon polycrystalline raw material 2 is melted by the high frequency induction heating coil 5 fixed in the furnace. To. The seed crystal fixed to the crystal holder 4 is brought into contact with the melting zone 3A of silicon, and the melt is solidified while pulling downward and increasing the diameter so as to have a desired straight body diameter, and reaches the straight body diameter. After that, the melt is solidified so as to maintain its straight body diameter to produce a silicon single crystal 3. At this time, by moving the silicon polycrystalline raw material 2 downward while rotating it at the same time, the lower end of the silicon polycrystalline raw material 2 is continuously melted, and an amount of melt required for single crystallization is supplied.
When the crystal has grown to some extent, it is held by the product single crystal weight holder 8.

[2] Structure of the polycrystalline raw material gripping tool 9 FIGS. 2 and 3 show the structure of the polycrystalline raw material gripping tool 9. FIG. 2A is a plan view seen from above of the horizontal position adjusting unit 12, which will be described later, and FIG. 2B is a side view. FIG. 3A is a plan view seen from above of the chuck portion 15 described later, and FIG. 3B is a cross-sectional view.
The polycrystalline raw material gripping tool 9 is a device for gripping the silicon polycrystal raw material 2. As shown in FIGS. 2A and 2B, the polycrystalline raw material gripping tool 9 includes an upper shaft 10, a support shaft 11, a horizontal position adjusting portion 12, a hanging lower portion 13, an inclination adjusting bolt 14, and a chuck portion 15. , A gripping bolt 16, and a heat shield plate 17.

The upper shaft 10 is connected to an elevating mechanism and a rotating mechanism (not shown), and elevates and rotates the silicon polycrystalline raw material 2 in the chamber.
The support shaft 11 is connected to the center of the upper shaft 10, a horizontal position adjusting portion 12 is provided around the support shaft 11, and a suspension lower portion 13 is connected to the lower end of the support shaft 11, which is a silicon polycrystalline raw material. Supports the load of 2.
Although the horizontal position adjusting unit 12 will be described in detail later, the support shaft 11 is moved in the horizontal direction, and the radial center position of the gripped silicon polycrystalline raw material 2 is aligned with the axis center of the upper shaft 10.

The hanging lower portion 13 is integrally provided at the lower end of the horizontal position adjusting portion 12, and is made of a circular plate-shaped body made of stainless steel, particularly SUS304. A hanging rod 13A is rotatably attached to the center of the hanging lower portion 13.
Further, although not shown, three female screw holes are formed around the support shaft 11 at a pitch of 120 ° in the vicinity of the outer periphery of the suspension lower portion 13.
The tilt adjusting bolt 14 is screwed into each female screw hole of the suspension lower portion 13, and the tip of the tilt adjusting bolt 14 comes into contact with the upper surface of the chuck portion 15. Then, by changing the protrusion amount of each tilt adjusting bolt 14, the tilt of the chuck portion 15 is changed, and the hanging posture of the silicon polycrystalline raw material 2 is adjusted.

As shown in FIGS. 3A and 3B, the chuck portion 15 is composed of a circular plate made of stainless steel, particularly SUS304, and a silicon polycrystal is formed in the center of the disk of the chuck portion 15. Apart from the rotation mechanism of the raw material 2, the hanging rod 13A is rotatably connected with a degree of freedom in the horizontal direction.
The chuck portion 15 is composed of two layers in which an upper plate 15A and a lower plate 15B are overlapped. In the upper plate 15A, five elongated holes 151 extending from the outer circumference toward the center in the radial direction are formed around the hanging rod 13A. In the lower plate 15B, five elongated holes 152 formed spirally from the outer periphery of the lower plate 15B toward the inside are formed around the hanging rod 13A.

The gripping bolt 16 as the locking portion is made of molybdenum or stainless steel, particularly SUS304, and grips the silicon polycrystalline raw material 2. The gripping bolt 16 includes a bolt 161, a positioning nut 162, a holding nut 163, a heat shield support nut 164, and a raw material holding plate 165. The holding nut 163, the heat shield support nut 164, and the raw material holding plate 165 may have an integral shape.
The bolt 161 is inserted at a plurality of overlapping positions of the elongated hole 151 of the upper plate 15A and the elongated hole 152 of the lower plate 15B, respectively, at five locations around the support shaft in the present embodiment. By rotating the upper plate 15A and the lower plate 15B relative to the hanging rod 13A, the radial position and the circumferential position of the bolt 161 are changed.

The positioning nut 162 is screwed to the upper end of the bolt 161 and once the radial position and the circumferential position of the bolt 161 are determined, the positioning nut 162 is tightened with the chuck portion 15 supported by the lower holding nut 163. Thereby, the gripping position of the gripping bolt 16 is positioned.
The heat shield plate support nut 164 is screwed apart from the lower portion of the holding nut 163 to support the heat shield plate 17 in a state of being separated from the chuck portion 15.

The raw material holding plate 165 is a stainless steel circular plate-shaped body provided at the lower end of the bolt 161. The raw material holding plate 165 is a circular plate having a diameter larger than the diameter of the bolt 161. The silicon polycrystalline raw material 2 is locked to the polycrystalline raw material gripper 9 by inserting the edge of the raw material holding plate 165 into the groove 2A formed at the upper end of the silicon polycrystalline raw material 2.

[3] Structure of the heat shield plate 17 FIG. 4 shows the heat shield plate 17 as the heat shield portion of the present embodiment.
The heat shield plate 17 is made of a circular plate made of stainless steel, particularly SUS304, and has a plate thickness of 0.8 mm or more. Five slits 171 are formed in the heat shield plate 17 from the outer peripheral edge toward the center, and bolts 161 of the gripping bolts 16 are inserted into the slits 171. A heat shield plate support nut 164 screwed into the bolt 161 abuts on the lower surface of the heat shield plate 17, and the heat shield plate 17 is supported in a state of being separated from the chuck portion 15.

The reason why the heat shield plate 17 is a disk-shaped body made of SUS304 having a thickness of 0.8 mm or more is that the tensile strength tends to decrease from about 400 ° C. in terms of the physical properties of the mechanical strength of the material of SUS304. This is because of consideration. Therefore, if it is shielded by the heat shield plate 17, the radiant heat due to the heating of the silicon polycrystalline raw material 2 is blocked, and the heat propagation due to the radiant heat to the upper chuck portion 15, the suspension lower portion 13, and the horizontal position adjusting portion 12 is prevented. , The chuck portion 15, the suspension lower portion 13, and the horizontal position adjusting portion 12 can be prevented from being deformed by heat. If the thickness is 0.8 mm or more, a shielding effect is expected, and 0.9 to 1.1 mm is preferable. If it is thicker than 1.2 mm, the increase in weight and the deformation due to thermal strain are related to the displacement of the gripping bolt 16, and as a result, the runout of the raw material is affected, which is not preferable.

[4] Structure of Horizontal Position Adjusting Unit 12 FIG. 5 shows a horizontal position adjusting unit 12 constituting the polycrystalline raw material gripping tool 9. 5 (A) is a plan view seen from above of the horizontal position adjusting unit 12, and FIG. 5 (B) is a cross-sectional view of the horizontal position adjusting unit 12.
As shown in FIG. 5, the horizontal position adjusting portion 12 includes a position adjusting portion main body 121, bolts 125, 126, and a hanging rod support portion 127.
The position adjusting unit main body 121 is composed of a stainless steel cylindrical body having an upper surface closed so as to surround the support shaft 11. A hole 122 into which the support shaft 11 is inserted is formed on the upper surface of the position adjusting portion main body 121. The hole 122 is formed to be larger than the diameter of the support shaft 11. The horizontal position of the horizontal position adjusting portion 12 with respect to the support shaft 11 is changed depending on where the support shaft 11 is inserted in the hole 122.

Female screw holes 123 and 124 are formed on the side surface of the position adjusting portion main body 121. The female screw holes 123 and 124 are formed in the left-right direction (temporarily referred to as the X-axis direction) in FIG. 5A and the vertical direction (temporarily referred to as the Y-axis direction) in FIG. 5A. That is, the female screw holes 123 and 124 are arranged to face each other, and the combination of the two sets of female screw holes 123 and 124 is formed in the directions orthogonal to each other in the X-axis direction and the Y-axis direction.
Further, the female screw holes 123 and the female screw holes 124 arranged so as to face each other have different screw pitches. Specifically, the female screw hole 123 is an M8 screw conforming to JIS B 0205 standard, and an M6 screw conforming to the female screw hole 124 standard.

The bolt 125 is screwed into the female screw hole 123, and the bolt 126 is screwed into the female screw hole 124. That is, the M8 bolt 125 is screwed into the female screw hole 123, and the M6 bolt 126 is screwed into the female screw hole 124.
The tips of the bolts 125 and 126 abut on the support shaft 11 and the horizontal positions of the horizontal position adjusting portions 12 are changed by changing the screwing positions of the bolts 125 and 126 facing each other. The horizontal position of the support portion 127 is changed. Specifically, the feed amount of the horizontal value by the bolt 125 and the bolt 126 can be adjusted with (M8 × 1P) − (M6 × 0.75P) = 0.25 mm as the minimum unit.

The hanging lower portion 13 is supported by the hanging rod support portion 127. When the chuck portion 15 is pushed down with respect to the suspension lower portion 13 by the tilt adjusting bolt 14 screwed into the suspension lower portion 13, the chuck portion 15 rotates with the suspension rod 13A rotatably attached to the center of the suspension lower portion 13 as a fulcrum. However, the relative posture between the hanging lower portion 13 and the chuck portion 15 changes.

[5] Actions and effects of the embodiment In such an embodiment, the suspension position of the silicon polycrystalline raw material 2 is adjusted as follows.
When the silicon polycrystalline raw material 2 is gripped by the chuck portion 15 of the polycrystalline raw material gripping tool 9, the approximate center position can be grasped. While gripping the silicon polycrystalline raw material 2, the inclination adjusting bolt 14 adjusts the vertical posture of the silicon polycrystalline raw material 2.

By adjusting the screwing positions of the bolt 125 and the bolt 126 of the horizontal position adjusting unit 12 and finely adjusting the horizontal position of the silicon polycrystalline raw material 2, the silicon polycrystalline raw material 2 is moved when the silicon polycrystalline raw material 2 is rotated. Avoid drawing a circular orbit with a certain radius.
When the silicon single crystal 3 is manufactured by the FZ furnace 1, the raw material holding plate 165 of the gripping bolt 16 is inserted into the groove 2A of the silicon polycrystalline raw material 2, so that the silicon polycrystalline raw material 2 thermally expands during heating. Also, the raw material holding plate 165 can be pushed out and bitten by the elongated holes 151 and the elongated holes 152 formed in the upper plate 15A and the lower plate 15B of the chuck portion 15 toward the radial center from the outer periphery. Therefore, there is no problem that the gripping force of the gripping bolt 16 is lowered or galling or the like occurs.

Since the heat shield plate 17 is arranged with a gap from the upper chuck portion 15, the silicon polycrystalline raw material 2 is heated by the high frequency induction heating coil 5, and the chuck portion 15 is thermally distorted due to the influence of the radiant heat generated. Can be generated and displaced, and the gripping bolt 16 can be prevented from being displaced accordingly. Therefore, even if the heat of the high-frequency induction heating coil 5 is likely to be transferred to the polycrystalline raw material gripping tool 9 in the latter half of the production of the silicon single crystal 3 in the FZ furnace 1, the heat shield plate 17 shields the heat. The gripping force does not decrease due to thermal deformation of the polycrystalline raw material gripping tool 9 due to heating. Further, by suppressing the heat transfer to the horizontal position adjusting portion 12, the gripping position is not eccentric, and it is possible to suppress an increase in runout with crystal growth.

A pair of female screw holes 123 of the position adjusting portion main body 121 are formed in the XY directions orthogonal to each other. Therefore, by adjusting the screwing position of the bolt 125 inserted into each female screw hole 123, the axis of the silicon polycrystalline raw material 2 can be aligned with the center of the FZ furnace 1. In particular, as described above, since the pitch of the female screw hole 124 of the M6 is smaller than that of the female screw hole 123 of the M8, the approximate position is adjusted with the bolt 125 of the M8, and the fine adjustment is made with the bolt 126 of the M6. It can be carried out. Therefore, since the silicon polycrystalline raw material 2 can be positioned with high accuracy, it is possible to prevent the silicon polycrystalline raw material 2 from drawing a circular orbit with a predetermined diameter during the growth of the silicon single crystal 3.
A heat shield plate 17 made of stainless steel or the like having a thickness of 0.8 mm or more can reduce the gap between the position adjusting portion main body 121 and the gripping bolt 16. Therefore, the heat shielding effect can be ensured in a narrow gap, and the deformation of the horizontal position adjusting portion 12 can be suppressed.

[6] Modifications of the Embodiment The present invention is not limited to the above-described embodiments, but also includes the modifications as shown below.
In the above-described embodiment, the above-mentioned horizontal position adjusting unit 12 forms female screw holes 123 and 124 in the X-axis direction and the Y-axis direction orthogonal to each other, and adjusts the horizontal position on two axes. , The present invention is not limited to this. For example, six female screw holes may be formed in the position adjusting portion main body 121 so as to surround the support shaft 11, and bolts may be screwed into the female screw holes to adjust the horizontal position. Further, three female screw holes 123 and 124 may be formed around the support shaft 11 and bolts may be screwed into the respective female screw holes 123 and 124 to adjust the horizontal position.

In the above-described embodiment, the female screw holes 123 facing each other are M8 screws conforming to JIS B0205, and the female screw holes 123 are M6 screws conforming to the same standard, but the present invention is not limited to this. For example, screws having different pitches conforming to the ISO standard may be adopted, and further, screws conforming to the inch screw standard conforming to JIS B 0206 may be used.

In the above-described embodiment, the gripping bolts 16 are provided at five locations on the chuck portion 15, but the present invention is not limited to this. That is, the structure may be such that six gripping bolts 16 are provided to hold the silicon polycrystalline raw material.
In addition, the specific structure, shape, and the like at the time of carrying out the present invention may be other structures and the like as long as the object of the present invention can be achieved.

Next, examples of the present invention will be described. The present invention is not limited to the examples.
[Example]
As described in the embodiment of the present invention, the horizontal position adjusting unit 12 adjusts the horizontal position of the silicon polycrystal raw material 2 by using the polycrystalline raw material gripping tool 9 provided with the horizontal position adjusting unit 12 and the heat shield plate 17. For those, silicon single crystal 3 was grown.
[Comparison example]
As shown in FIG. 6, the silicon single crystal 3 was grown using the polycrystalline raw material gripper 100 without the horizontal position adjusting portion and the heat shield plate.

The results are shown in FIGS. 7 and 8. In the case of FIG. 7, which is a comparative example, it was confirmed that the runout tends to increase in the graph as the crystal grows, especially in the latter half length.
In the case of FIG. 8 as an example, it was confirmed that the graph remained flat by using the horizontal position adjusting unit 12 and the heat shield plate 17, and the runout was stable regardless of the pulling length. rice field.
Further, although not shown, the displacement amount of the gripping bolt 16 is 60% more than the conventional one because the thermal deformation of the chuck portion 15 is suppressed even when the displacement amount of the gripping bolt 16 is confirmed by CFD (computation fluid dynamics). It was confirmed that the results were suppressed to some extent.

1 ... FZ furnace, 2 ... silicon polycrystalline raw material, 2A ... groove, 3 ... silicon single crystal, 3A ... molten zone, 4 ... crystal holder, 5 ... high frequency induction heating coil, 6 ... heat insulation tube, 8 ... product single crystal Weight holder, 9 ... Polycrystalline raw material gripper, 10 ... Upper shaft, 11 ... Support shaft, 12 ... Horizontal position adjustment part, 13 ... Suspension lower part, 13A ... Suspension rod, 14 ... Tilt adjustment bolt, 15 ... Chuck part , 15A ... upper plate, 15B ... lower plate, 16 ... gripping bolt, 17 ... heat shield plate, 121 ... position adjustment unit body, 122 ... hole, 123 ... female screw hole, 124 ... female screw hole, 125 ... bolt, 126 ... bolt , 127 ... Suspension bar support, 151 ... Long hole, 152 ... Long hole, 161 ... Bolt, 162 ... Positioning nut, 163 ... Holding nut, 164 ... Heat shield support nut, 165 ... Raw material holding plate, 171 ... Slit ..

Claims (4)

FZ (Floating Zone) A tool for gripping polycrystalline raw materials in FZ furnaces that grips silicon polycrystalline raw materials in furnaces.
A support shaft that supports the load of the silicon polycrystalline raw material, and
A plurality of locking portions for locking the silicon polycrystalline raw material, and
A chuck portion that grips the silicon polycrystalline raw material via the plurality of locking portions, and a chuck portion.
A horizontal position adjusting portion connected below the support shaft and horizontally adjusting the position of the chuck portion and the plurality of locking portions.
A heat shield portion that is arranged with a gap below the chuck portion to shield radiant heat from the silicon polycrystalline raw material, and a heat shield portion.
Equipped with
The horizontal position adjusting unit is
A position adjusting unit main body provided so as to surround the support shaft and having a plurality of female screw holes formed around the support shaft.
A plurality of bolts screwed into each of the female screw holes and having a tip abutting on the support shaft are provided.
A polycrystalline raw material gripping tool for an FZ furnace, characterized in that the female screw holes facing each other and the screw pitches of the bolts are different. In the polycrystalline raw material gripping tool of the FZ furnace according to claim 1.
The plurality of female screw holes are formed in pairs in the directions orthogonal to each other.
A pair of female thread holes that are orthogonal to each other have one thread pitch smaller than the other thread pitch.
A polycrystalline raw material gripping tool for an FZ furnace, characterized in that the screwing position of a bolt screwed into the pair of female screw holes is adjusted. In the polycrystalline raw material gripper of the FZ furnace according to claim 1 or 2.
The chuck portion is composed of an upper plate and a lower plate.
A plurality of elongated holes extending from the outer circumference toward the center in the radial direction are formed on the upper plate and the lower plate, respectively.
A polycrystalline raw material gripping tool for an FZ furnace, wherein the plurality of locking portions are inserted through the plurality of elongated holes. The polycrystalline raw material gripper of the FZ furnace according to any one of claims 1 to 3.
The heat shield is a polycrystalline raw material gripping tool for an FZ furnace, characterized in that the heat shield is made of a stainless steel plate having a thickness of 0.8 mm or more.

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