WO2003106742A1

WO2003106742A1 - Seed crystal holding jig and process for producing single crystal

Info

Publication number: WO2003106742A1
Application number: PCT/JP2003/007319
Authority: WO
Inventors: 大國　禎之; 園川　将; 水石　孝司; 太田　友彦
Original assignee: 信越半導体株式会社
Priority date: 2002-06-12
Filing date: 2003-06-10
Publication date: 2003-12-24
Also published as: JP4135405B2; JP2004018271A

Abstract

Seed crystal holding jig (11) capable of, at the time of drawing up a single crystal in accordance with the Cyochralski method, holding a seed crystal by bringing tapered end face (15) of insert fit member (14) into pressed contact with tapered hold face (18) of seed crystal (5), the taper of the end face (15) in reverse relationship to that of the hold face (18), characterized in that the holding jig (11) is furnished with two or more insert fit members, these insert fit members having a height equal to that of main body (12) of the holding jig and provided at equal intervals round center axis (19) of the holding jig. Preferably, the insert fit members are constituted of a carbon fiber reinforced carbon composite material or an isotropic sintered carbon, while the main body of holding jig comprises eiher a carbon fiber reinforced carbon composite material or a reinforced isotropic sintered carbon or molybdenum. Thus, there are provided a seed crystal holding jig and a process for producing a single crystal, which enable securely drawing up a single crystal of high purity without breakage of seed crystal or holding jig even when a single crystal of large weight, such as 170 kg or more, is grown.

Description

Description Seed crystal holding jig and manufacturing method of single crystal

The present invention relates to a jig for holding a seed crystal used for pulling a silicon single crystal or a compound semiconductor single crystal or the like by a Chiral Clarke method (CZ method), and a method for manufacturing a single crystal. Background art

Conventionally, for example, when manufacturing a silicon single crystal, a silicon seed crystal is immersed in a molten material obtained by melting polycrystalline silicon, and then the silicon seed crystal is pulled up while being rotated to convert the silicon single crystal. There is known a manufacturing method called the Chiyolarski method (CZ method) for growing.

FIG. 7 shows an example of a single crystal pulling apparatus used for the CZ method. The single crystal pulling apparatus 20 includes a crucible 3 for accommodating a silicon melt 2 in a chamber 10, a crucible support shaft 4 for rotating the crucible 3, and a rotating mechanism (not shown); It comprises a seed crystal holding jig 6 for holding the seed crystal 5, a wire 7 for lifting the seed crystal holding jig 6, and a winding mechanism (not shown) for rotating or winding the wire 7. In addition, a heater 8 is arranged around the crucible 3, and a heat insulating material 9 is arranged around the heater 8 to pull up the single crystal.

In order to produce a silicon single crystal using the single crystal pulling apparatus 20, a silicon polycrystal is heated in a crucible 3 to a temperature higher than the melting point and melted, and a wire 7 is unwound to melt. The tip of seed crystal 5 is contacted or immersed in the center of 2. Next, the crucible 3 is rotated in an appropriate direction, the wire 7 is wound while being rotated, and the seed crystal 5 is pulled up to start growing a single crystal. After that, by appropriately controlling the pulling rate and temperature, the growth of almost cylindrical growth Crystal 1 can be obtained.

As the seed crystal holding jig 6 for holding the seed crystal 5 described above, various types of structures have been proposed in the past, and as shown in FIG. There is a lock type holding jig. In this holding jig 6 a, a reverse-tapered fitting 24 is inserted from the side of the main body of the holding jig 6 a into the tapered holding surface 18 of the seed crystal 5, and A ring-shaped outer cover 26 is put on the main body so as to prevent the insertion fitting 24 from falling out. As a result, the holding surface 18 of the seed crystal 5 is pressed against the end surface 15 of the fitting 24 so that the seed crystal 5 is held.

FIG. 9 shows another holding jig 6b of the key lock type. キー Insert the key 25 into the fitting 24 and lock it so that the end face 15 of the insertion fitting 24 is formed. Is pressed against the holding surface 18 of the seed crystal 5 to hold the seed crystal 5.

As another holding jig, there is, for example, a pin lock type as shown in FIG. The holding jig 6 c is for locking the seed crystal by inserting a cylindrical pin 27 into a circular hole provided between the jig body and the seed crystal 5. In the case of the holding jig 6c, the point between pin 27 and the seed crystal 5 is smaller than that of the key lock type, which holds the seed crystal by pressing the tapered surface into contact. Since the seed crystal 5 is liable to be damaged due to contact, and high processing accuracy is required, a tapered key-mouth type holding jig is preferably used.

When a single crystal is manufactured by holding a seed crystal with a key-open type seed crystal holding jig, the total weight of the single crystal grown after the seed crystal is applied to the holding jig and the seed crystal. If the holding jig or the seed crystal breaks due to insufficient strength, the single crystal falls on the extremely high-temperature molten raw material and damages the grown single crystal or equipment. Therefore, it is necessary to use a holding jig that can securely hold the single crystal to be grown.

For example, the weight of a conventional silicon single crystal having a diameter of less than 200 mm was at most about 120 _kg , but in recent years it has become mainstream. Such large silicon single crystals can exceed 170 kg. As a result, the load applied to the holding jig becomes extremely large. In particular, in growing a single crystal having a diameter of 300 mm, it is desired to safely and surely pull a long crystal desirably exceeding 250 kg.

Conventionally, isotropic sintered carbon has been generally used as a material for a seed crystal holding jig. A holding jig of such a material does not cause metal contamination of single crystal and can withstand a load of about 160 kgf, so that the diameter is less than 20 Omm. It can be used to grow single crystals. However, it is difficult to obtain a load bearing capacity of more than 170 kgf, which is required for growing silicon single crystals with a diameter of 300 mm.

Conventionally, various measures have been taken to prevent the holding jig or the seed crystal from being damaged. For example, Japanese Patent Application Laid-Open No. 11-197882 discloses a heat-resistant cushion such as a carbon fiber or metal fiber flute between a seed crystal and a contact surface of a seed crystal holding jig. A holding jig and a seed crystal holding jig that prevent breakage of a seed crystal by one point concentration of load stress by interposing a material are disclosed.

However, this holding jig is not strong enough to pull a heavy single crystal of 170 kg or more, and when the cushion material is pressed, the fine powder is removed from the cushion material. May be scattered and mixed into the molten raw material, thereby lowering the purity of the single crystal.

Also, Japanese Patent Application Laid-Open No. 9-123541 discloses that at least two surfaces of a seed crystal having a rectangular cross section are pressed against a seed crystal of a holding jig toward an inner surface of an insertion hole. A crystal holding jig is disclosed. By using this holding jig, the seed crystal can be accurately positioned and held without tilting, and the holding force is increased.

However, even with such a holding jig, the strength is not sufficient to pull a heavier single crystal in the future, and the seed crystal or the holding jig may be broken during the pulling.

Even if a key-lock type seed crystal holding jig is used in this way, if a higher weight single crystal is to be grown in the future, a part of the holding jig will be damaged. The contaminants are scattered, and the impurities are mixed into the high-purity raw material melt, thereby deteriorating the purity quality of the single crystal, or the seed crystal or the holding jig is damaged and the growing single crystal falls. There was a problem that there was a possibility.

Disclosure of the invention

Therefore, the present invention can safely and reliably pull a high-purity single crystal without breaking the seed crystal or holding jig even when growing a high-weight single crystal of 170 kg or more. It is intended to provide a seed crystal holding jig and a method for producing a single crystal.

In order to achieve the above object, according to the present invention, when pulling a single crystal by the Chiyo-Kralski method, an end face of a reverse fitting with a reverse taper is attached to a holding surface of a tapered seed crystal. A holding jig for holding the seed crystal by pressing, comprising two or more of the above-mentioned fittings, wherein these inserting fittings are at the same height as the main body of the holding jig and around the center axis. In addition, a seed crystal holding jig characterized by being provided at equal intervals is provided.

By using such a seed crystal holding jig, it is possible to hold the seed crystal by pressing the holding surface of the seed crystal with a plurality of inserts provided at equal intervals around the same height. The load from the growing single crystal is evenly distributed. Therefore, the load resistance of the seed crystal / holding jig is improved, and even a heavy single crystal can be reliably pulled with high purity.

揷 The fitting preferably has a tensile strength of 200 kgf / cm ² or more and an elastic modulus of 200 O kgf Zm ni ² or less, and is made of carbon fiber reinforced carbon. It is preferably made of a composite material or isotropic sintered carbon.

揷 If the fitting is too hard, the seed crystal may break when subjected to a high load by pressing against it, but the tensile modulus is more than ²⁰⁰ kgf / cm2 and the elastic modulus is 200 if kgf / rn m ² following揷嵌tool, Ru can and child to prevent this Yo I Do Yabu壌effectively. Also, if the material of the insert is carbon fiber reinforced carbon composite material or isotropic sintered carbon, the strength of the insert is sufficient, and since the insert has flexibility, it can be broken. In addition, seed crystal destruction can be effectively prevented, and metal contamination of the grown single crystal can be prevented.

The holding jig body preferably has a tensile strength of at least 20 O kgf Z cm ² and an elastic modulus of at least 800 kgf / mm ² , and particularly, the material is carbon fiber. Preferably, it is a reinforced carbon composite, reinforced isotropic sintered carbon, molybdenum or at least one of them. If the holding jig body has a tensile strength of 200 kgf / cm ² or more and an elastic modulus of 800 kgf Z mm ² or more, the strength of the holding jig body can be sufficiently increased. Particularly, materials such as carbon fiber reinforced carbon composite material, reinforced isotropic sintered carbon, and molybdenum have extremely high heat resistance, so that sufficient strength can be maintained even in a high-temperature chamber. .

According to the present invention, the seed crystal is held by pressing the end face of a fitting having a reverse taper of the seed crystal holding jig against the tapered holding surface of the seed crystal by holding the seed crystal. In a method for producing a single crystal by the Kralski method, as a seed crystal, two or more tapered holding surfaces are provided at the same height and at equal intervals around a central axis. The seed crystal is held using a holding jig provided with an insertion fitting for pressing all the holding surfaces of the seed crystal as the seed crystal holding jig. Also, a method for producing a single crystal characterized by pulling up the single crystal is provided.

By holding the seed crystal in this way, the load of the grown single crystal can be evenly dispersed, so that even a heavy single crystal can be reliably pulled up and manufactured with a diameter of 30%. The productivity of a single crystal having a large diameter of 0 mm or more can be improved, and the material of the holding jig can be prevented from being scattered and the single crystal can be prevented from being contaminated.

In the holding jig of the present invention, since two or more fittings are provided at the same height of the main body of the holding jig and at equal intervals around the central axis, the holding jig is used for seeding. By holding the crystals, the load that increases as the crystals grow can be evenly dispersed, and the load bearing capacity of the seed crystal and the seed crystal holding jig can be greatly improved. As a result, even large silicon single crystals with a diameter of, for example, 30 O mm or more and a mass of 170 kg or more can be safely pulled up with high purity, improving the yield of single crystal production. Cost reductions can also be achieved. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic sectional view showing an example of a seed crystal holding jig of the present invention. (a) Longitudinal section

(b) Cross section of main body

Figure 2 is a schematic diagram of the seed crystal that is retained.

FIG. 3 is a view showing another example of a seed crystal holding jig according to the present invention and a seed crystal held.

(a) Schematic sectional view of the holding jig body

(b) Perspective view of retained seed crystal

FIG. 4 is a schematic sectional view of still another example of the main body of the seed crystal holding jig according to the present invention.

FIG. 5 is a diagram showing a test seed crystal used in the tensile test.

(a) Example

(b) Comparative example

Figure 6 is a diagram illustrating the outline of the tensile test.

Figure 7 shows an example of a single crystal pulling apparatus using the Chiyo-Kralski method. FIG. 8 is a schematic diagram showing an example of a conventional key-lock type seed crystal holding jig.

FIG. 9 is a schematic diagram showing another example of a conventional keylock type seed crystal holding jig.

FIG. 10 is a schematic diagram showing an example of a pin-lock type seed crystal holding jig. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be specifically described, but the present invention is not limited thereto.

FIG. 1 shows an example of a seed crystal holding jig of the present invention, and FIG. 2 shows a seed crystal to be held. Seed crystal 5 is a quadrangular prism, and two tapered holding surfaces 18 are provided at the same height and opposed around central axis 19 ′. On the other hand, the holding jig 11 is formed at the same height as the main body 12 and with two through holes 13 for inserting the insertion fitting 14 around the center axis 19 facing each other. In these through holes 13, a fitting 14 having a taper opposite to the taper of the holding surface 18 of the seed crystal 5 is inserted so as to face the through hole 13. The end surface 15 of such a fitting 14 and the holding surface 18 of the seed crystal 5 are provided at corresponding positions, and furthermore, the angle of the taper of the holding surface 18, The angle of the taper at the end of the tool 14 is formed at the same angle. Then, the jig body 12 is covered with a ring-shaped mantle 16 so as to prevent the fitting tool 14 from coming off, so that the jig body 12 is locked. Are pressed equally to hold the seed crystal 5.

FIG. 3 shows a cross section of another main body of the seed crystal holding jig according to the present invention and a seed crystal held by the main body.

A cylindrical seed crystal insertion hole 17 is formed at the center of the holding jig main body 12 shown in FIG. 3 (a). Also, three through holes 13 are formed at the same height of the jig body 12 and around the center axis 19 at equal intervals, and these through holes 13 are respectively formed. The insertion fitting can be inserted.

On the other hand, as shown in Fig. 3 (b), the retained seed crystal 5 'has a columnar shape as a whole, and has three tapers with the same angle as the taper of the end face of the fitting. The holding surface 18 is provided at the same height and opposed around the center axis 19. The seed crystal 5 ′ is held by pressing all three holding surfaces 18 with 揷 fittings. FIG. 4 shows a cross section of the holding jig main body 12 having four insertion fittings. The four through holes 13 are at the same height as the holding jig main body 12, and the center axis is It is provided at equal intervals around 19. When a seed crystal is held by such a holding jig, a seed crystal having four holding surfaces corresponding to the insertion fitting is used, and all these holding surfaces are pressed against the end face of the fitting. Try to keep it.

As for the material of the holding jig of the present invention, it is necessary to use a material having a compressive strength and a tensile strength sufficiently strong to safely pull up a heavy crystal having a high weight. When a hard material such as molybdenum, stainless steel, or an alloy thereof with an elastic modulus of more than 1000 kg Zinm ² is used, a seed crystal consisting of a single crystal, which is a brittle material, is pressed. At times, the seed crystal may be damaged to lower the load-bearing capacity, or the seed crystal may be broken. Therefore, the insert has a tensile strength of S200 to 700 kgf / to prevent the breakage of the insert itself and to prevent damage and destruction of the seed crystal and the jig body. cm ² and a conductivity coefficient of 500 to 200 kgf Zmm ² is preferable.

If the tensile strength of the insert is less than ²⁰⁰ kgf / cm2, the insert itself may be broken, so it includes the commonly used CIP (Cold Isostatic Pressing) material (CIP — A) also because the material, ² 0 O kgf / cm 2 or more is preferred rather, good Ri favored properly the CIP material molded high strength - those materials containing (CIP B), 3 0 0 kgf Z cm 2 or more It is. On the other hand, if the tensile strength of the material of the insert exceeds 700 kgf / cm ² , the seed crystal or the jig body may be damaged or broken.

Further, when the elastic modulus of the inserted instrument is less than _{5 0 0 k g f / mm} 2, carry the risk that the strength reduction due to deformation easily stress concentration occurs, whereas, the ² 0 0 0 kgi / mm 2 If it exceeds, the seed crystal and the jig body may be damaged or destroyed.

As a preferable material of the insertion fitting, a carbon fiber reinforced carbon composite material (C / C material) or isotropic sintered carbon can be used. Made of these materials. With a fitting, the seed crystal is not broken, and the end face is appropriately crushed when the seed crystal is pressed, so that surface contact can be obtained. Even if the fine powder is mixed into the raw material melt, it is simply There is no metal contamination of the crystal. However, for example, when an isotropic sintered carbon material having a tensile strength of less than ²⁰⁰ kgf no c in ² is used, the strength becomes insufficient and there is a risk of compressive fracture. When the insert is made of an isotropic sintered carbon material having a tensile strength of at least 0 kgf / cm ^2, more preferably at least 30 O kgi Z cm ² (the range of general carbon materials) However, both the insert and the seed crystal are less likely to be crushed, which is preferable.

On the other hand, metal can be suitably used as a material of each member other than the fitting. For example, the body of the holding jig can be molybdenum, carbon fiber reinforced carbon composite, reinforced isotropic sintered carbon, or at least one of them. For example, if the holding jig body is made of a metal with a high melting point such as molybdenum, the strength of the jig body will be extremely high, and the strength will be sufficiently high even in a chamber that becomes hot during pulling of a single crystal. Can be maintained. If a metal material is used for the holding jig body, the fine metal powder may be mixed into the raw material melt during the growth of the single crystal and cause metal contamination.Therefore, cover the metal surface of the body with a carbon material. To prevent metal contamination.

The holding jig body, tensile strength force S 2 0 0~ 2 0 0 0 0 kgf / cm 2 der is, the elastic coefficient is the well 8 0 0~ 3 0 0 0 0 kgf / mm 2 for this Is preferred. If the tensile strength of the holding jig body is less than 200 kgί / cm ² , the jig body will be easily ruptured, while if it exceeds 2000 kgf / cm ² , the seed crystal will be damaged. Or there is a risk of being destroyed.

Further, there is a possibility that弹性coefficient holding jig body incurs 8 0 0 kg strength reduction due to deformation easily stress concentration and ί is less than / mm ^2, whereas, more than 3 0 0 0 0 kgi / mm 2 And the seed crystal may be damaged or destroyed. Further, the above-mentioned isotropic sintered carbon can be used as a material of each member other than the insertion fitting, and all the members of the holding jig may be made of isotropic sintered carbon. However, if the holding jig body is made of isotropic sintered carbon, If the number of through holes into which the fittings are fitted increases, the cross-sectional area of that part may decrease and the strength may be insufficient.Therefore, two 揷 fittings 14 as shown in Fig. 1 are opposed to each other. It is preferable to adopt a structure in which they are arranged in a position.

Next, a case where a silicon single crystal is manufactured by the CZ method using the seed crystal holding jig 11 shown in FIG. 1 will be described.

First, a seed crystal 5 as shown in FIG. 2 having a tapered holding surface 18 corresponding to the end surface 15 of the insertion fitting 14 is prepared. The seed crystal 5 is inserted into the seed crystal insertion hole 13 of the jig 11, and the insertion fitting 14 is inserted into each through hole 13 of the holding jig body 12, and Put a ring-shaped jacket 16 on the body 12 and lock it so that 14 does not come off. Thus, the end face of the fitting 14 can hold the seed crystal 5 by pressing the holding surface 18 of the seed crystal 5 against the holding face 18.

Thus, the tip of the seed crystal 5 held by the holding jig 11 of the present invention is immersed in the molten silicon material accommodated in the rutupo of the single crystal pulling apparatus as shown in FIG. The seed crystal holding jig 11 is rotated, and the single crystal 1 is grown following the seed crystal 5 by pulling the jig directly upward by an upper pulling means (wire winding mechanism). Can be.

As the single crystal 1 grows, a downward pulling load is applied to the seed crystal 5, and this load is transmitted to the fitting 14 via the end surface 15 that presses the holding surface 18 of the seed crystal 5. In addition, a load is transmitted from the lower surface of the fitting 14 to the jig main body 12, and a tensile stress that tears the main body at the A--A 'face of the body in contact with the lower surface of the fitting 14 is applied. Occurs.

At this time, with the holding jig 11 of the present invention, the load applied to the seed crystal 5 can be evenly distributed to each of the inserts 14, and the dispersed load is applied to the center of the holding jig 11. Since it is distributed evenly as viewed from the shaft 19, there is no uneven load. Therefore, in the holding jig 11 of the present invention, the load-bearing strength of the holding jig main body is improved as compared with the conventional holding jig having one insertion fitting.

In the conventional structure having one fitting shown in FIGS. 8 and 9, all loads are concentrated at positions eccentric from the central axes of the seed crystal holding jigs 6a and 6b. Fitting The tool 24 acts like a bottle opener, and growing a heavy single crystal is likely to tear the jig body apart. This becomes more remarkable even when a plurality of fittings are provided, unless the fittings are provided at equal intervals around the center axis, because the cross-sectional area of the holding jig body is reduced.

Also, if the surface of the seed crystal is scratched, it is easily cleaved and the load capacity is significantly reduced.However, in the holding jig of the present invention, the seed crystals are arranged at equal angular intervals around the central axis. Since it is held in a suspended state by a plurality of fittings, it is pressed against the inner wall surface of the center hole of the holding jig, or rubs against the inner wall surface and scratches the seed crystal surface. There is no such thing. Therefore, when the holding jig of the present invention is used, the load bearing strength of the seed crystal itself is also improved.

As described above, when a single crystal is grown using the seed crystal holding jig according to the present invention, a high crystal having a diameter of 30 O mm or more and a weight of 170 kg or more, particularly more than 250 kg. Even heavy silicon single crystals can be pulled up reliably without breaking the holding jig and seed crystal.

Hereinafter, Examples and Comparative Examples of the present invention will be described.

(Tensile test)

A tensile test was conducted to measure the strength of the seed crystal and the seed crystal holding jig.

In the tensile test, two holding jigs (type of the present invention) and one holding jig (conventional type) were used as the holding jigs, respectively, as shown in Fig. 5 (a) or (b) A test seed crystal (15 mm X 15 mm X 125 mm) with notches (holding surfaces) at both ends as shown in Fig. 7 was held. As the material of the holding jig, two types of isotropic sintered carbon materials and pure molybdenum were used. The test was performed as shown in Figure 6. Specifically, both ends of the test seed crystal 5a (5b) are held by holding jigs 12a and 12b, respectively, and one holding jig 12b is fixed to the fixed end, and the other end is fixed to the other end. The holding jig 12a was fixed to a shaft to which a tensile load could be applied via a flexible joint. Pull A load cell is provided at the end of the shaft to which a load can be applied, so that the tensile load when the seed crystal or the seed crystal holding jig is broken can be measured. In the test, the holding jig 12a was pulled at a constant speed of 0.1 mm / min, and the seed crystal 5a (5b) or the seed crystal holding jigs 12a and 12b were pulled until they were broken. The load at the time of failure was measured continuously. Table 1 shows the holding jigs used for the test and the measurement results. Table 1>

CIP A: Bow I Tensile strength 250kgf / cm ² , Modulus of elasticity 1000kgf / mm ²

CIP B: Bow I Tensile strength 700 kgf / cm ² , Modulus of elasticity 1300 kgf / mm ²

Moripden: pure moripden Tensile strength 7000 18200 kgf / cm ² , Modulus of elasticity 28000 kgf / mm ^{2 When a} seed crystal or a single crystal with a weight corresponding to the load to break the seed crystal holding jig is grown, There is a great risk that the grown single crystal will fall. Therefore, in practice, a safety factor of 3 is preferably used for growing a single crystal up to a weight of 1 to 3 of the crushing load obtained in the tensile test, and this was set as the load bearing capacity. For example, it was evaluated that a jig broken by a tensile load of 300 kgf in a tensile test can be safely used for growing a single crystal of 100 kg or less.

As is evident from the results shown in Table 1, 揷 When the seed crystal holding jigs of Comparative Examples 1 to 3 having only one fitting were used, the target resistance of 170 kg or more was achieved. To grow a heavy silicon single crystal with a diameter of 30 O mm without reaching the load Shows that the strength is not enough. In particular, in Comparative Example 3 in which the entire holding jig was made of high-strength molybdenum, the holding jig itself was not broken, but the seed crystal broke under the weakest breaking load. This is considered to be due to the fact that since there was only one fitting and good surface contact was not obtained, the load concentrated on the contact point of the seed crystal.

On the other hand, when the seed crystal holding jigs of Examples 1 to 3 provided with the two fittings were used, the withstand load became 170 kgf or more in each case. In particular, the material of the holding jig of Example 1 was the same as that of Comparative Example 1, but the load capacity was improved by about 87% compared with that of Comparative Example 1, and the single crystal of up to 187 kg It turned out that we could cope with training.

In the holding jig of Example 2, the load resistance was 250 kg, and in Example 3 in which the material of the holding jig body and the jacket was made of molybdenum, the breaking load was 160,000. kgf, which indicates that single crystals can be grown up to 533 kg.

Note that the present invention is not limited to the above embodiment. The above embodiment is an exemplification, and has substantially the same configuration as the technical idea described in the claims of the present invention, and any device having the same function and effect can be obtained. It is included in the technical scope of the present invention.

For example, in the above-described embodiment, the locking type using the ring-shaped outer jacket has been described, but the locking method is not limited, and the key is inserted into the insertion fitting as shown in FIG. 9. It may be of a type that can be sucked at. The overall shape of the seed crystal to be held is not particularly limited. In addition to holding a cylindrical seed crystal in the holding jig shown in Fig. 1, it can also hold a hexagonal or octagonal seed crystal. Alternatively, a material whose tip is machined into a shape such as a conical shape may be used.

Claims

The scope of the claims

1. When the single crystal is pulled up by the Chiral Clarke method, the holding surface for holding the seed crystal by pressing the end face of the reverse-tapered insertion fitting against the holding surface of the tapered seed crystal. A jig, wherein two or more of the jigs are provided, and these jigs are provided at the same height of the main body of the holding jig and at equal intervals around the center axis. A jig for holding a seed crystal.

2. The seed crystal according to claim 1, wherein the fitting has a tensile strength of not less than 200 kgί / cm ² and an elastic modulus of not more than 200 kgf Z mm ^2. Holding jig.

3. The seed crystal holding jig according to claim 1, wherein the metal fitting is made of carbon fiber reinforced carbon composite material or isotropic sintered carbon.

4. The holding jig body according to claim 1, wherein the holding jig has a tensile strength of 200 kgf / cm ² or more and a elasticity coefficient of 800 kgf / mm ² or more. A seed crystal holding jig according to any one of the preceding claims.

5. The method according to claim 4, wherein the main body of the holding jig is made of carbon fiber reinforced carbon composite material, reinforced isotropic sintered carbon, molybdenum, or at least any one of them. Seed crystal holding jig.

6. Hold the seed crystal by pressing the end face of the fitting with the reverse taper of the seed crystal holding jig against the tapered holding surface of the seed crystal, hold the seed crystal, and use the Chiyo Klarski method. In the method for producing a crystal, as a seed crystal, the two or more tapered holding surfaces are at the same height and are equally spaced around a central axis. In addition to using the seed crystal provided in the above, as a seed crystal holding jig, the seed crystal is formed by using a holding jig having an insertion fitting for pressing all the holding surfaces of the seed crystal. A method for producing a single crystal, comprising holding and pulling the single crystal.