JP4862836B2 - Single crystal manufacturing apparatus and single crystal manufacturing method - Google Patents

Description

  The present invention relates to an apparatus and a method for producing a silicon single crystal by a Czochralski method (hereinafter abbreviated as CZ method).

Hereinafter, a conventional single crystal manufacturing apparatus using the Czochralski method will be described taking silicon single crystal growth as an example.
FIG. 6 is a schematic sectional view showing an example of a conventional single crystal manufacturing apparatus.
A single crystal production apparatus 101 used for producing a silicon single crystal by the CZ method generally encloses the crucibles 106 and 107 capable of moving up and down, which contains a raw material melt 105, and the crucibles 106 and 107. A heater 108 disposed in the main chamber 102 is disposed in a main chamber 102 for growing a single crystal, and a pulling chamber 103 for accommodating and taking out the grown single crystal is connected to the upper portion of the main chamber 102. When producing a single crystal using such a single crystal production apparatus 101, while the seed crystal 112 is immersed in the raw material melt 105 and gently rotated upward while rotating, a rod-like single crystal is grown. In order to obtain a desired diameter and crystal quality, the crucibles 106 and 107 are raised in accordance with crystal growth so that the height of the melt surface is always maintained.

  When growing the single crystal, after immersing the seed crystal 112 attached to the seed holder 113 in the raw material melt 105, the seed crystal 112 is gently rotated while being rotated in a desired direction by a pulling mechanism (not shown). The wire 115 is wound up to grow a single crystal 104 at the tip of the seed crystal 112. However, in order to eliminate dislocations generated when the seed crystal 112 is deposited in the melt, the initial crystal is temporarily grown. The crystal is narrowed down to about 3 to 5 mm, and when the dislocation is removed, the diameter is expanded to a desired diameter to grow a single crystal 104 having a desired quality.

At this time, the pulling speed of the constant diameter portion having a constant diameter of the single crystal 104 depends on the diameter of the single crystal to be pulled, but is very slow, about 0.4 to 2.0 mm / min. When trying to pull up forcibly quickly, the single crystal being grown is deformed and a cylindrical product having a constant diameter cannot be obtained. Alternatively, slip dislocation occurs in the single crystal 104 or problems such as the single crystal 104 being separated from the melt and becoming a product occur, and there is a limit to increasing the crystal growth rate. .
However, in the production of the single crystal 104 by the CZ method, increasing the growth rate of the single crystal 104 is one of the major means for improving the productivity and reducing the cost. However, many improvements have been made to increase the growth rate of the single crystal 104.

  The growth rate of the single crystal 104 is determined by the heat balance of the growing single crystal 104, and it is known that heat released from the surface of the single crystal can be efficiently removed in order to increase the growth rate. Yes. At this time, if the cooling effect of the single crystal 104 can be enhanced, a more efficient single crystal can be manufactured. Furthermore, it is known that the quality of the crystal changes depending on the cooling rate of the single crystal 104. For example, a grown-in defect formed during the growth of a single crystal in a silicon single crystal can be controlled by the ratio between the temperature gradient in the crystal and the pulling rate (growth rate) of the single crystal. A defect-free single crystal can also be grown (see Patent Document 1). Therefore, it is important to enhance the cooling effect of the growing single crystal both in manufacturing defect-free crystals and in increasing productivity by increasing the growth rate of the single crystal.

In order to efficiently cool the single crystal 104 in the CZ method, it is effective to absorb the radiant heat from the single crystal 104 in a forcedly cooled object such as a chamber without directly applying the radiation from the heater 108 to the crystal. A screen structure is an example of a device structure that can achieve this (see Patent Document 2). However, in this structure, if the screen is shaped so as to avoid contact due to the rise of the crucible, it is necessary to reduce the inner diameter of the upper part of the screen.
In addition, while the crystal is being pulled, an inert gas is flowed to prevent contamination by the oxidizing gas, but there is a problem that the cooling effect of the single crystal cannot be utilized.

On the other hand, there has been proposed a structure having a rectifying cylinder for rectifying an inert gas and a heat insulating ring for blocking direct radiation from a heater and a raw material melt on the rectifying cylinder (see Patent Document 3). In this method, the cooling effect of the single crystal by the inert gas can be expected, but it cannot be said that the cooling capacity is high in that the radiation heat from the single crystal is absorbed by the cooling chamber.
Therefore, as a method for solving the problems of the screen and the rectifying cylinder and cooling efficiently, there has been proposed a single crystal manufacturing apparatus in which a water-cooled cooling cylinder is arranged around the crystal (see Patent Document 4). In this method, the outside of the cooling cylinder is protected by a cooling cylinder protective material such as a protective cover such as a graphite material, and the heat of the single crystal can be efficiently removed from the inside of the cooling cylinder.

However, even in the single crystal manufacturing apparatus using the rectifying cylinder and the cooling cylinder, an oxidizing gas formed by the raw material melt and oxygen coming out of the crucible is generated and deposited on the inner wall of the low temperature chamber. There was a problem that dirt due to the adhesion of oxides acted as a heat insulating material or a light shielding material and hindered the cooling effect.
Further, there is disclosed a rectifying cylinder capable of observing the shape of a growing single crystal while providing the effect of the rectifying cylinder by providing a quartz window plate on the rectifying cylinder (see Patent Document 5). In the same manner as described above, there is a problem that the oxide adheres to the outside of the quartz window plate to cause fogging in the window and reduce the cooling effect.
For this reason, particularly when a plurality of single crystals are grown from one crucible, the cooling effect is reduced by the adhesion of oxides, so the quality differs for each single crystal, and it has been necessary to correct it.

JP-A-11-157996 Japanese Patent Publication No.57-40119 JP-A 64-65086 International Publication No. WO01 / 57293 Pamphlet Japanese Patent Laid-Open No. 3-97688

  The present invention has been made in view of the above-described problems, and while rectifying the inert gas downstream from the gas inlet of the pulling chamber to the vicinity of the single crystal, the inner wall surface of the main chamber and the side surface outside the rectifying cylinder An object of the present invention is to provide a single crystal manufacturing apparatus and a manufacturing method capable of preventing the cooling effect of radiant heat from a single crystal from decreasing with the lapse of time by preventing the oxide from being deposited on the surface.

In order to achieve the above object, according to the present invention, at least a crucible for storing a raw material melt and a main chamber for storing a heater for heating the raw material melt, and an upper portion of the main chamber are connected and grown. A single chamber by a Czochralski method having a pulling chamber in which the single crystal is pulled up and housed, a gas inlet provided in the pulling chamber, and a rectifying cylinder extending downward from the ceiling of the main chamber. A crystal manufacturing apparatus, wherein a gas introduction port is installed outside a rectification cylinder in the main chamber, and an inert gas is allowed to flow from the gas introduction port outside the rectification cylinder device Ru is provided.
Thus, in the single crystal manufacturing apparatus of the present invention, the gas introduction port is installed outside the rectifying cylinder in the main chamber, and the inert gas is allowed to flow from the gas introduction port outside the rectifying cylinder, It is possible to suppress the deposition of oxide on the inner wall surface of the main chamber and the outer side surface of the rectifying cylinder, and to prevent the cooling effect of radiant heat from the single crystal from decreasing with time.

In this case, it is not preferable to include a baffle plate to induce inert gas to flow outside of the flow-guide cylinder along the inner wall surface of the main chamber.
Thus, if a baffle plate is provided that guides the inert gas flowing outside the rectifying cylinder along the inner wall surface of the main chamber, it is possible to prevent oxide from being deposited on the inner wall surface of the main chamber. It can prevent effectively and can prevent more effectively that the cooling effect of the radiant heat from a single crystal falls over time.

At this time, it is not preferable to include a baffle plate to induce inert gas to flow outside of the flow-guide cylinder along the outer sides of the rectifying tube.
In this way, if the baffle plate that guides the inert gas flowing outside the rectifying cylinder along the outer side surface of the rectifying cylinder is provided, oxide is deposited on the outer side surface of the rectifying cylinder. Can be more effectively prevented, and the cooling effect of the radiant heat from the single crystal can be more effectively prevented from decreasing over time.
A baffle plate for guiding the inert gas flowing outside the rectifying cylinder along the inner wall surface of the main chamber; and the inert gas flowing outside the rectifying cylinder outside the rectifying cylinder If a baffle plate that guides along the side surface is provided, it is possible to more effectively prevent oxide from being deposited on the inner wall surface of the main chamber and the outer side surface of the rectifying cylinder. It can prevent even more effectively that the cooling effect of radiant heat falls with progress of time.

The present invention also includes a main chamber for storing at least a crucible for storing a raw material melt and a heater for heating the raw material melt, and an upper portion of the main chamber connected to the upper portion of the main chamber so that the grown single crystal is pulled up and stored. Using a Czochralski method single crystal manufacturing apparatus having a pulling chamber, a gas inlet provided in the pulling chamber, and a flow straightening tube extending downward from the ceiling of the main chamber An inert gas is allowed to flow from the gas inlet of the pulling chamber to the inside of the rectifying cylinder, and a gas inlet is installed outside the rectifying cylinder in the main chamber. that provides a method for manufacturing a single crystal for manufacturing a single crystal while supplying an inert gas from outside the gas inlet.
An inert gas is allowed to flow from the gas inlet of the pulling chamber to the inside of the rectifying cylinder, and a gas inlet is installed outside the rectifying cylinder in the main chamber, and also from the gas inlet outside the rectifying cylinder. By producing a single crystal while flowing an inert gas, it is possible to suppress the deposition of oxide on the inner wall surface of the main chamber and the outer side surface of the rectifying cylinder, and the cooling effect of the radiant heat from the single crystal is reduced over time. It can be prevented from decreasing with the passage of time.

At this time, the inert gas to flow outside of the flow-guide cylinder said not preferable that flow along the inner wall surface of the main chamber.
In this way, by flowing the inert gas that flows outside the flow straightening tube along the inner wall surface of the main chamber, it is possible to more effectively prevent oxide from being deposited on the inner wall surface of the main chamber. Moreover, it can prevent more effectively that the cooling effect of the radiant heat from a single crystal falls with progress of time.

At this time, it is not preferable to flow the inert gas to flow outside of the flow-guide cylinder along the outer sides of the rectifying tube.
In this way, it is possible to more effectively prevent oxide from being deposited on the outer side surface of the rectifying cylinder by flowing the inert gas flowing outside the rectifying cylinder along the outer side surface of the rectifying cylinder. It is possible to more effectively prevent the cooling effect of the radiant heat from the single crystal from decreasing with time.
In addition, an inert gas flowing outside the rectifying cylinder is caused to flow along the inner wall surface of the main chamber, and an inert gas flowing outside the rectifying cylinder is allowed to flow along the outer side surface of the rectifying cylinder. Thus, it is possible to more effectively prevent oxide from being deposited on the inner wall surface of the main chamber and the outer side surface of the rectifying cylinder, and the cooling effect of the radiant heat from the single crystal is reduced with time. This can be prevented even more effectively.

In the present invention, in the single crystal manufacturing apparatus, an inert gas is allowed to flow from the gas inlet of the pulling chamber to the inside of the rectifying cylinder to rectify near the single crystal, and the gas inlet is provided outside the rectifying cylinder in the main chamber. Install and manufacture single crystals while flowing an inert gas from the gas inlet outside the rectifying cylinder, so that it is possible to suppress the accumulation of oxide on the inner wall surface of the main chamber and the outer side surface of the rectifying cylinder. It is possible to prevent the cooling effect of the radiant heat from the single crystal from decreasing over time.
As a result, particularly when growing a plurality of single crystals from one crucible, adjustment of single crystal growth conditions and inter-order correction logic due to the difference in the number of produced single crystals can be eliminated. Therefore, the operation can be simplified and a stable crystal quality can be obtained.

Hereinafter, although an embodiment is described about the present invention, the present invention is not limited to this.
In order to improve productivity and reduce costs in the production of a single crystal by the conventional CZ method, increasing the growth rate of the single crystal is one of the major means. Is known to efficiently remove the heat released from the surface of the single crystal. Also in the production of defect-free crystals, it is important to increase the cooling effect of the single crystal being grown.

However, in a conventional single crystal manufacturing apparatus that uses a rectifying cylinder to improve the cooling effect, an oxidizing gas formed by the raw material melt and oxygen coming from the crucible is generated and deposited on the inner wall surface of the main chamber. However, there is a problem that the dirt due to the adhesion of these oxides acts as a heat insulating material or a light shielding material and hinders the cooling effect.
As for the outer side surface of the rectifying cylinder, especially when a quartz member is provided on the rectifying cylinder (for example, a quartz window plate for confirming the state of the single crystal being grown), the quartz member is similar to the above. When the oxide is deposited on the outer surface of the quartz member, the quartz member becomes cloudy, and at the same time, there is a problem that the cooling effect obtained by the quartz member efficiently passing radiation from the single crystal to the chamber is reduced.

  Therefore, the present inventor has intensively studied in order to prevent the cooling effect from decreasing as described above. As a result, in the conventional single crystal manufacturing apparatus, the inert gas flowing in from the gas inlet of the pulling chamber flows inside the flow straightening tube, passes through the surface of the raw material melt, and flows into the upper space in the main chamber. Since it is discharged from the gas outlet, it is possible to prevent the oxidizing gas from precipitating inside the rectifying cylinder, but this is not possible outside, and it is deposited on the inner wall of the main chamber and the outer side of the rectifying cylinder. We focused on the accumulation of oxide. And in order to prevent this, it discovered that an inert gas should just flow from the outer side of the rectifying cylinder in a main chamber.

  That is, the single crystal manufacturing apparatus of the present invention has a gas introduction port installed outside the rectifying cylinder in the main chamber, and an inert gas is allowed to flow also from the gas introduction port outside the rectifying cylinder. Further, it is possible to prevent the oxide from being deposited on the outer side surface of the rectifying cylinder, and to prevent the cooling effect of the radiant heat from the single crystal from decreasing with time.

FIG. 1 is a schematic cross-sectional view showing an example of the single crystal production apparatus of the present invention.
As shown in FIG. 1, the single crystal manufacturing apparatus 1 includes a crucible 6 and 7 for storing a raw material melt 5, a heater 8 for heating and melting the raw material, and the like stored in the main chamber 2. A pulling mechanism (not shown) for pulling up the grown single crystal 4 is provided on the upper portion of the pulling chamber 3 connected to.

  A pulling wire 15 is unwound from a pulling mechanism attached to the upper part of the pulling chamber 3, and a seed holder 13 for attaching a seed crystal 12 is connected to the tip of the pulling wire 15 and attached to the tip of the seed holder 13. The single crystal 4 is formed below the seed crystal 12 by immersing the seed crystal 12 in the raw material melt 5 and winding the pulling wire 15 by a pulling mechanism.

  The crucibles 6 and 7 are composed of a quartz crucible 6 that directly accommodates the raw material melt 5 inside, and a graphite crucible 7 for supporting the crucible outside. The crucibles 6 and 7 are supported by a crucible rotating shaft 16 that can be rotated and moved up and down by a rotation drive mechanism (not shown) attached to the lower part of the single crystal manufacturing apparatus 1, and the melt surface in the single crystal manufacturing apparatus 1. In order to keep the melt surface at a fixed position so that the crystal diameter and the crystal quality do not change due to the change of the crystal, the crucible 6 is reduced by the amount of the melt reduced as the single crystal 4 is pulled while rotating in the opposite direction to the crystal. , 7 is raised.

A heater 8 is disposed so as to surround the crucibles 6 and 7, and a heat insulating member 9 for preventing heat from the heater 8 from being directly radiated to the main chamber 2 is provided outside the heater 8. It is provided so as to surround the periphery.
Further, for the purpose of discharging the oxide generated in the furnace to the outside of the furnace, an inert gas such as argon gas is introduced from the gas inlet 11 provided in the upper part of the pulling chamber 3, Rectified near the single crystal 4 being pulled up, passes through the surface of the raw material melt 5, passes over the upper edges of the crucibles 6, 7, and is discharged from the gas outlet 10. Thereby, it is possible to prevent the oxide from being deposited on the inside of the rectifying cylinder, the upper edge of the crucible, and the like.

The main chamber 2 and the pulling chamber 3 are made of a metal having excellent heat resistance and thermal conductivity, such as stainless steel, and are water-cooled through a cooling pipe (not shown).
When the single crystal 4 is grown, the seed crystal 12 attached to the seed holder 13 is immersed in the raw material melt 5, and then the seed crystal 12 is rotated in a desired direction by a pulling mechanism (not shown). The wire 15 is gently wound up, and the single crystal 4 is grown at the tip of the seed crystal 12, but in order to eliminate the dislocation that occurs when the seed crystal 12 is deposited on the raw material melt 5, The crystal is narrowed down to about 3 to 5 mm, and when the dislocation is removed, the diameter is expanded to a desired diameter to grow a single crystal 4 having a desired quality. Alternatively, without using the seed squeezing, a dislocation-free seeding method is used in which the seed crystal 12 is sharply contacted with the raw material melt 5 so that the seed crystal 12 is immersed in a predetermined diameter and then pulled up. The single crystal 4 can be grown by application.
Up to this point, the configuration is the same as that of a conventional single crystal manufacturing apparatus.

In the single crystal manufacturing apparatus according to the present invention, a gas introduction port is provided outside the rectifying cylinder in the main chamber, and an inert gas is allowed to flow from the gas introduction port outside the rectifying cylinder.
As described above, the gas inlet 17 is installed outside the rectifying cylinder in the main chamber, and if an inert gas is allowed to flow from the gas inlet 17 outside the rectifying cylinder, the gas is introduced into the upper space of the main chamber. It is possible to prevent the oxide from accumulating on the inner wall surface of the main chamber and the outer side surface of the flow straightening tube, and to prevent the cooling effect of radiant heat from the single crystal from decreasing over time. Can do.

At this time, it is preferable to provide a baffle plate that guides the inert gas flowing outside the flow straightening tube along the inner wall surface of the main chamber.
FIG. 2 shows a schematic view of an example of the baffle plate that can be used in the present invention.
As shown in FIG. 2, the baffle plate has a shape that is opened outward in the horizontal direction at the ceiling of the main chamber so that the inert gas flows along the inner wall surface of the main chamber.

The baffle plate 18 guides the inert gas flowing outside the rectifying cylinder 14 along the inner wall surface of the main chamber 2, so that it is more effective to deposit oxide on the inner wall surface of the main chamber 2. The heat removal effect from the main chamber does not change with time, and the cooling effect of the radiant heat from the single crystal 4 can be more effectively prevented from decreasing with time.
Here, as shown in FIG. 2, a gas ejection ring 19 in which gas ejection ports 20 are provided at equal intervals in the circumferential direction can be connected to the gas introduction port 17. The gas outlet 20 is provided toward the outer side in the horizontal direction of the gas jet ring 19 (in the direction of the dotted arrow in FIG. 2), and the gas is jetted in this direction.

By installing the baffle plate 18 together with such a gas ejection ring 19, the inert gas flowing along the inner wall surface of the main chamber 2 can be made to flow uniformly and evenly in the main chamber 2. It is possible to more effectively prevent oxide from being deposited on the wall surface. However, the present invention is not limited to the presence or absence of the gas ejection ring 19.
The flow rate of the gas flowing along the inner wall surface of the main chamber 2 is preferably 10% to 3 times the flow rate of the gas flowing from the gas inlet 11 provided in the pulling chamber 3. If the flow rate is 10% or more, the effect of preventing the deposition of oxide on the inner wall surface of the main chamber 2 can be reliably achieved. Further, when the flow rate is 3 times or less, it is possible to prevent the oxide from flowing backward toward the raw material melt 5 to inhibit the growth of the single crystal 4. However, these conditions are not limited to this, and may be appropriately set depending on the size in the furnace.

Further, at this time, it is preferable that a baffle plate for guiding the inert gas flowing outside the rectifying cylinder 14 along the outer side surface of the rectifying cylinder 14 is provided.
FIG. 3 shows a schematic view of an example of the baffle plate that can be used in the present invention.
As shown in FIG. 3, the baffle plate 18 ′ has a shape that opens downward in the vertical direction of the rectifying cylinder 14 so that the inert gas flows along the outer side surface of the rectifying cylinder 14.
The baffle plate 18 ′ guides the inert gas flowing outside the rectifying cylinder 14 along the outer side surface of the rectifying cylinder 14, so that oxide is deposited on the outer side surface of the rectifying cylinder 14. Can be more effectively prevented, and the cooling effect of the radiant heat from the single crystal 4 can be more effectively prevented from decreasing over time.

Here, as shown in FIG. 3, a gas ejection ring 19 ′ in which gas ejection ports 20 ′ are provided at equal intervals in the circumferential direction can be connected to the gas introduction port 17. The gas outlet 20 'is provided downward (in the direction of the dotted arrow in FIG. 3) in the vertical direction of the gas outlet ring 19', and gas is jetted in this direction.
By installing the baffle plate 18 ′ together with such a gas ejection ring 19 ′, the gas flowing along the outer side surface of the rectifying cylinder 14 can be made to flow evenly and evenly on the outer periphery of the rectifying cylinder 14. It is possible to more effectively prevent oxide from being deposited on the outer side surface of the substrate. However, the present invention is not limited to the presence or absence of the gas ejection ring 19 ′.

  The flow rate of the gas flowing along the outer side surface of the flow straightening cylinder 14 is preferably 10% or more and 2 times or less than the flow rate of the gas flowing from the gas inlet 11 provided in the pulling chamber 3. If the flow rate is 10% or more, the effect of preventing the oxide from being deposited on the outer side surface of the rectifying cylinder 14 can be reliably achieved. If the flow rate is twice or less, it is possible to prevent the oxide from flowing backward toward the raw material melt 5 to inhibit the growth of the single crystal 4. However, these conditions are not limited to this, and may be appropriately set depending on the size in the furnace.

At this time, the baffle plate 18 that guides the inert gas flowing outside the rectifying cylinder 14 along the inner wall surface of the main chamber 2 and the inert gas flowing outside the rectifying cylinder 14 are rectified. It is also possible to provide both baffle plates 18 ′ that are guided along the outer side surface of the cylinder 14.
As described above, the baffle plate 18 that guides the inert gas flowing outside the rectifying cylinder 14 along the inner wall surface of the main chamber 2 is provided, and the inert gas flowing outside the rectifying cylinder 14 is If the baffle plate 18 ′ that guides along the outer side surface of the rectifying cylinder 14 is provided, it is more effective that oxide is deposited on the inner wall surface of the main chamber 2 and the outer side surface of the rectifying cylinder 14. Therefore, it is possible to more effectively prevent the cooling effect of the radiant heat from the single crystal 4 from decreasing with time.

Here, a gas ejection ring in which gas ejection ports are provided at equal intervals in the circumferential direction can be connected to the gas introduction port 17 outside the rectifying cylinder 14. Here, the gas jet port flows gas along both the inner wall surface of the main chamber 2 and the outer side surface of the rectifying cylinder 14, so that the lower side in the vertical direction of the jet ring and the outer side in the horizontal direction are arranged. It is provided for both sides. In this case, in order to change the flow rate of both, the size of the ejection port may be changed.
Alternatively, two gas ejection rings may be provided so that the gas flows along both the inner wall surface of the main chamber 2 and the outer side surface of the rectifying cylinder 14. In any case, the present invention is not limited to the presence or absence of the gas ejection ring.

In the method for producing a single crystal according to the present invention, as described above, an inert gas is allowed to flow from the gas inlet 11 of the pulling chamber 3 to the inside of the rectifying cylinder 14 to rectify it near the single crystal, and at the same time, the main chamber 2 A gas inlet 17 is installed outside the inner rectifying cylinder 14, and the single crystal 4 is grown while flowing an inert gas from the gas inlet 17. The single crystal 4 is pulled up into the pulling chamber 3 by winding the wire 15 by the pulling mechanism.
By doing so, it is possible to prevent oxide from being deposited on the inner wall surface of the main chamber 2 and the outer side surface of the rectifying cylinder 14, and the cooling effect of the radiant heat from the single crystal 4 decreases with time. Can be prevented.

At this time, as shown in FIG. 1, it is preferable that an inert gas that flows outside the rectifying cylinder 14 flows along the inner wall surface of the main chamber 2.
In this way, by flowing the inert gas flowing outside the rectifying cylinder 14 along the inner wall surface of the main chamber 2, it is possible to more effectively prevent oxide from being deposited on the inner wall surface of the main chamber 2. It is possible to more effectively prevent the cooling effect of the radiant heat from the single crystal 4 from decreasing with time.

Further, at this time, as shown in FIG. 4, it is preferable to flow the inert gas flowing outside the rectifying cylinder 14 along the side surface outside the rectifying cylinder 14.
In this way, it is more effective that oxide is deposited on the outer side surface of the rectifying cylinder 14 by flowing the inert gas flowing outside the rectifying cylinder 14 along the outer side surface of the rectifying cylinder 14. It is possible to prevent the cooling effect of the radiant heat from the single crystal 4 from decreasing with time.

  Further, as shown in FIG. 5, the inert gas that flows outside the rectifying cylinder 14 is caused to flow along the inner wall surface of the main chamber 2, and the inert gas that flows outside the rectifying cylinder 14 is rectified. By flowing along the outer side surface of the cylinder 14, it is possible to more effectively prevent oxide from being deposited on the inner wall surface of the main chamber 2 and the outer side surface of the rectifying cylinder 14. It is possible to more effectively prevent the cooling effect of the radiant heat from decreasing with the passage of time.

After pulling up the first single crystal as described above, a raw material having the same weight as that of the pulled single crystal is added to the crucibles 6 and 7 to replenish the reduced raw material melt. A second single crystal can be produced by this method.
In this way, when performing so-called multi-pooling in which a plurality of single crystals are manufactured from one crucible using the method for manufacturing a single crystal of the present invention, the cooling effect of radiant heat from the single crystal is increased as the order advances. Since it can be prevented from decreasing, each crystal can be pulled up under exactly the same conditions, and adjustment of single crystal growth conditions for each order and inter-order correction logic can be dispensed with. Therefore, the operation can be simplified and a stable crystal quality can be obtained.

As described above, according to the present invention, in the single crystal manufacturing apparatus, an inert gas is caused to flow from the gas inlet 11 of the pulling chamber 3 to the inside of the rectifying cylinder 14 and to the outside of the rectifying cylinder 14 in the main chamber 2. Since the single crystal 4 is manufactured while the gas inlet 17 is installed and the inert gas is allowed to flow from the gas inlet 17 outside the rectifying cylinder 14, oxidation is performed on the inner wall surface of the main chamber 2 and the outer side surface of the rectifying cylinder 14. An object can be prevented from being deposited, and the cooling effect of the radiant heat from the single crystal 4 can be prevented from decreasing with time.
As a result, particularly when growing a plurality of single crystals from one crucible, adjustment of the growth conditions of single crystals, correction logic between orders, and the like due to the difference in the number of produced single crystals can be eliminated. Therefore, the operation can be simplified and a stable crystal quality can be obtained.

  Note that the rectifying cylinder in the present invention only needs to have a function of rectifying the inert gas downstream from above the rectifying cylinder to the vicinity of the single crystal, regardless of whether or not it has its name and other functions. Anything that does not have a gas rectifying effect can be applied to the present invention. For example, a cooling cylinder that extends downward from the ceiling of the main chamber and is forcibly cooled by a cooling medium is within the range of the flow straightening cylinder of the present invention.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to these.

Example 1
Using a single crystal manufacturing apparatus as shown in FIG. 1, a silicon single crystal having a diameter of 12 inches (300 mm) was manufactured by a magnetic field application Czochralski method (MCZ method). The diameter of the crucible 6 was 32 inches (800 mm). Further, the flow rate of the argon gas flowing in from the gas introduction port 17 was set to 10% as compared with the gas amount of the argon gas flowing in from the gas introduction port 11. Further, a baffle plate 18 and a gas ejection ring 19 as shown in FIG. 2 are provided, and an argon gas that flows outside the rectifying cylinder 14 is caused to flow along the inner wall surface of the main chamber 2.

Using such a single crystal manufacturing apparatus, three single crystals were grown at the same growth rate and pulled up from one crucible to become defect-free crystals by a multi-pooling method.
At this time, a sample was cut out from the pulled first and third single crystals, and it was confirmed by selective etching whether or not a defect-free crystal was formed.
As a result, the target portion of the first single crystal became a defect-free crystal, but defects were detected in the third single crystal. The defect-free ratio was about 30%, confirming that the results were better than those of the comparative examples.

(Example 2)
1 except that the flow rate of the argon gas flowing in from the gas inlet port 17 in FIG. 1 is twice the flow rate of the argon gas flowing in from the gas inlet port 11 under the same conditions as in Example 1. Crystals were produced and evaluated in the same manner as in Example 1.
As a result, all the targeted portions of the first crystal were defect-free crystals, but some defects were detected in the third crystal. The ratio of defect-free was about 80%. It was confirmed that the results were better than those of Comparative Example and Example 1.

(Example 3)
Using a single crystal manufacturing apparatus as shown in FIG. 4, a silicon single crystal having a diameter of 12 inches (300 mm) was manufactured by a magnetic field application Czochralski method (MCZ method). The diameter of the crucible 6 was 32 inches (800 mm). Further, the flow rate of the argon gas flowing in from the gas introduction port 17 was set to be the same as that of the argon gas flowing in from the gas introduction port 11. Further, a baffle plate 18 ′ and a gas ejection ring 19 ′ as shown in FIG. 3 are provided, and an argon gas that flows to the outside of the rectifying cylinder 14 is caused to flow along the outer side surface of the rectifying cylinder 14.

Using such a single crystal manufacturing apparatus, three single crystals were grown at the same growth rate and pulled up from one crucible to become defect-free crystals by a multi-pooling method. And evaluation similar to Example 1 was performed.
As a result, all the targeted portions of the first crystal were defect-free crystals, but some defects were detected in the third crystal. The defect-free ratio was about 50%, and it was confirmed that the result was better than the comparative example.

Example 4
Using a single crystal manufacturing apparatus as shown in FIG. 5, the flow rate of argon gas flowing from the gas inlet 17 along the inner wall surface side of the main chamber 2 is compared with the amount of argon gas flowing from the gas inlet 11. The flow rate of argon gas flowing from the gas inlet 17 along the outer side surface of the rectifying cylinder 14 is the same as that of the argon gas flowing from the gas inlet 11. A single crystal was produced under the same conditions as in Example 1, and the same evaluation as in Example 1 was performed.
As a result, all the targeted portions of both the first and third crystals became defect-free crystals.
Thereby, it has confirmed that it was a result better than a comparative example, Example 2, and Example 3. FIG.

(Comparative example)
A single crystal was produced under the same conditions as in Example 1 except that a conventional single crystal production apparatus as shown in FIG. 6 was used, and the same evaluation as in Example 1 was performed. As a result, the target portion of the first crystal was all defect-free, but no defect-free crystal was obtained for the third crystal.

(test)
A single crystal was produced under the same conditions as in the comparative example except that the growth rate of the third single crystal was reduced by about 2% compared to the first single crystal, and the same evaluation as in the comparative example was performed.
As a result, all the targeted portions of the first and third single crystals were defect-free crystals.
Thus, in the comparative example, it was confirmed that the oxide was deposited in the main chamber or the like before the third single crystal was manufactured, and the cooling effect of the radiant heat from the single crystal was reduced.
On the other hand, in the present invention, as in Example 4, it can be seen that the present invention can grow defect-free crystals without reducing the pulling rate.
The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

It is the schematic sectional drawing which showed one form of the single crystal manufacturing apparatus which concerns on this invention. It is the schematic which showed an example of the baffle which can be used by this invention. It is the schematic which showed another example of the baffle which can be used by this invention. It is the schematic sectional drawing which showed another form of the single crystal manufacturing apparatus which concerns on this invention. It is the schematic sectional drawing which showed another form of the single crystal manufacturing apparatus which concerns on this invention. It is the schematic sectional drawing which showed an example of the conventional single crystal manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Single crystal manufacturing apparatus, 2 ... Main chamber, 3 ... Pulling chamber,
4 ... single crystal, 5 ... raw material melt, 6, 7 ... crucible,
8 ... heater, 9 ... heat insulating member, 10 ... gas outlet,
11, 17 ... Gas inlet, 12 ... Seed crystal, 13 ... Seed holder,
14 ... Rectifying cylinder, 15 ... Wire, 16 ... Crucible rotating shaft,
18, 18 '... baffle plate, 19, 19' ... gas ejection ring, 20, 20 '... gas ejection port.

Claims (4)

At least a main chamber for storing a crucible for storing the raw material melt and a heater for heating the raw material melt, a pulling chamber connected to the upper portion of the main chamber, and a grown single crystal is pulled up and stored; A single crystal manufacturing apparatus according to the Czochralski method, comprising a gas inlet provided in the pulling chamber and a rectifying cylinder extending downward from a ceiling portion of the main chamber, wherein the rectifying cylinder in the main chamber along a gas inlet was placed on the outside of the state, and are not to flow an inert gas from outside the gas inlet of the rectifier tube, an inert gas further flows to the outside of the flow-guide cylinder on the inner wall of the main chamber single crystal manufacturing apparatus according to claim der Rukoto those having a baffle plate to induce manner. The single crystal manufacturing apparatus according to claim 1, further comprising a baffle plate that guides an inert gas that flows outside the rectifying cylinder along the outer side surface of the rectifying cylinder. At least a main chamber for storing a crucible for storing the raw material melt and a heater for heating the raw material melt, a pulling chamber connected to the upper portion of the main chamber, and a grown single crystal is pulled up and stored; A method for producing a single crystal using a Czochralski method single crystal production apparatus having a gas inlet provided in the pulling chamber and a rectifying cylinder extending downward from the ceiling of the main chamber. An inert gas is allowed to flow from the gas inlet of the pulling chamber to the inside of the rectifying cylinder, and a gas inlet is installed outside the rectifying cylinder in the main chamber, and the gas inlet is provided outside the rectifying cylinder. A method for producing a single crystal, comprising producing a single crystal while flowing an inert gas along the inner wall surface of the main chamber . 4. The method for producing a single crystal according to claim 3, wherein an inert gas that flows to the outside of the rectifying cylinder is caused to flow along the outer side surface of the rectifying cylinder.

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