JP4984092B2 - Single crystal manufacturing apparatus and single crystal manufacturing method - Google Patents

Description

  The present invention relates to an apparatus for producing a single crystal such as silicon by the Czochralski method, and a method for producing a single crystal.

  Conventionally, a Czochralski method (CZ method) for growing a high-purity silicon single crystal for a semiconductor from a silicon melt in a quartz crucible supported by a graphite crucible is known as a method for growing a silicon single crystal. Yes. In this method, a seed crystal is attached to a seed crystal holder suspended inside the chamber above the crucible via a wire from a rotation / pull-up mechanism provided at the top of the chamber, the wire is drawn out, and the seed crystal is melted into silicon. By contacting the solution, pulling up the seed crystal by dash necking method or dislocation-free seeding method, etc., producing a seed drawn portion etc. from the silicon melt, and then gradually growing the crystal to the desired diameter, A dislocation-free single crystal ingot having a desired plane orientation can be obtained.

FIG. 7 shows a general configuration example of a single crystal manufacturing apparatus using a conventional wire.
The single crystal manufacturing apparatus 101 includes a top chamber 103, a middle chamber 104, a bottom chamber 105, and the like, which include crucibles 108 and 109 for storing a raw material melt 107, a heater 110 for heating and melting a polycrystalline raw material, and the like. Stored in the main chamber. The crucibles 108 and 109 are supported by a crucible rotating shaft 121 that can be rotated up and down by a rotation drive mechanism (not shown). Further, a heater 110 for heating the raw material melt 107 is disposed so as to surround the crucibles 108 and 109, and heat from the heater 110 is directly radiated to the main chamber outside the heater 110. The heat insulation member 122 for preventing is provided so that the circumference | surroundings may be surrounded.

  A pulling mechanism 120 for pulling up the grown single crystal rod 106 is provided on the upper portion of the pull chamber 102 provided continuously on the main chamber. A pulling wire 119 is unwound from the pulling mechanism 120, and a seed holder 118 for attaching the seed crystal 117 is connected to the tip of the pulling wire 119, and the seed crystal 117 attached to the tip of the seed holder 118 is used as a raw material melt. The single crystal rod 106 is pulled up and grown below the seed crystal 117 by immersing in 107 and winding the pulling wire 119 with the pulling mechanism 120.

  Further, an inert gas such as argon gas is introduced into the pull chamber 102 and the main chamber from a gas inlet 123 provided on the upper portion of the pull chamber 102 for the purpose of discharging the impurity gas generated in the furnace to the outside of the furnace. Then, it passes through the upper part of the pulling single crystal rod 106 and the raw material melt 107 and flows through the main chamber, and is discharged from the gas outlet 124 provided in the base plate 127.

  Further, in order to efficiently cool the single crystal rod 106 being pulled, a cooling cylinder 125 and a cooling auxiliary member 126 extending downward from the cooling cylinder 125 so as to surround the single crystal rod 106 being pulled inside the main chamber are provided. Is provided. A single crystal pulling device is disclosed in which a sealed space is provided around the cooling water channel of such a cooling cylinder to prevent the cooling water supplied to the cooling cylinder from leaking into the chamber (Patent Document 1). reference).

  Each chamber is provided with a cooling water passage (not shown), and cooling water for cooling the chamber is circulated inside the cooling water passage to protect each chamber. Is blocked so that the radiant heat of the heater 110 inside is not transmitted to the outside of the single crystal manufacturing apparatus 101.

  Conventionally, this cooling water supply pressure is set at one location in the factory's centralized cooling water supply system, and abnormalities in the flow rate of the cooling water supplied are detected by a flow switch installed on the outlet side of the cooling water flow path of each chamber. It was. However, if the pressure adjustment in the centralized supply device becomes impossible and the cooling water pressure exceeds the design pressure of the chamber (for example, 0.5 MPa), the chamber may be damaged and cooling water may enter the furnace. In case of intrusion, the cooling water may come into contact with the melted raw material melt.

  Also, when the cooling water stops flowing, an alarm is issued, but the flow switch is mechanically structured (consisting of a lever and a spring), and the switch works with the pressure of the cooling water. It was difficult to set the alarm. In addition, since the cooling water is always flowed, the mechanical parts of the flow switch are deteriorated and a malfunction occurs, for example, a problem that the alarm is not generated at the set alarm flow rate occurs, and the flow rate management is not perfect. Furthermore, when the system that informs the decrease in the flow rate fails, it is not possible to confirm the decrease in the flow rate of the cooling water, so it is necessary to take a double measure.

Japanese Patent Laid-Open No. 2005-145762

  The present invention has been made in view of the above-described problems, and controls the abnormal water pressure so as not to act on each chamber, supplies cooling water at an appropriate flow rate, and facilitates detection of cooling water abnormality. An object of the present invention is to provide a single crystal manufacturing apparatus and a single crystal manufacturing method capable of improving the abnormality detection time.

  In order to achieve the above object, according to the present invention, a raw material in a crucible accommodated in a chamber is heated by a heater to form a raw material melt, and a seed crystal is poured into the heated raw material melt. An apparatus for producing a single crystal by a Czochralski method for growing a single crystal below, wherein the chamber is divided into a plurality of parts, and each of the divided chambers is cooled by supplying and discharging cooling water. A cooling water path, and on each of the cooling water paths, a pressure adjusting valve for adjusting a supply pressure of cooling water supplied to the chamber, a flow rate adjusting valve and a flow meter for adjusting a flow rate, and the cooling water A pressure release valve for releasing the supply pressure, and a digital flow meter for measuring the flow rate of the cooling water discharged from the chamber. The flow rate and pressure of the cooling water supplied to each of the divided chambers are Set the pressure regulating valve and flow rate regulating valve for each cooling water path, and periodically measure and record the flow rate of cooling water discharged from each of the divided chambers with the digital flow meter. When the recorded flow rate is smaller than a predetermined value, an alarm is issued, and the cooling water supply pressure for each cooling water path is measured, and when the pressure exceeds a predetermined value, the cooling water path A single crystal manufacturing apparatus is provided, wherein the cooling water supply pressure is released by the pressure release valve (Claim 1).

  As described above, the chamber is divided into a plurality of parts, each of the divided chambers has an individual cooling water path for cooling by supplying and discharging cooling water, and on each of the cooling water paths, A pressure adjusting valve for adjusting the supply pressure of the cooling water supplied to the chamber, a flow rate adjusting valve and a flow meter for adjusting the flow rate, a pressure release valve for releasing the supply pressure of the cooling water, and discharged from the chamber A digital flow meter for measuring the flow rate of cooling water, and supplying the flow rate and pressure of cooling water supplied to each of the divided chambers to the pressure adjusting valve and the flow rate adjusting valve for each of the cooling water paths. Set, periodically measure and record the flow rate of cooling water discharged from each of the divided chambers with the digital flow meter, and alert if the recorded flow rate is less than a predetermined value The cooling water supply pressure for each of the cooling water paths is measured, and when the pressure exceeds a predetermined value, the cooling water supply pressure is released by the pressure release valve of the cooling water path If so, control can be performed so that abnormal water pressure does not act on each chamber, and damage to the chamber due to excessive pressure can be prevented. In addition, it is possible to efficiently cool the chambers by supplying cooling water having an appropriate flow rate to the respective chambers, and to prevent local increase in temperature. Furthermore, the abnormality of the cooling water can be easily detected by the change in the flow rate, and the abnormality detection time can be improved.

At this time, it is preferable that the cooling water supply pressure to be set is 0.1 to 0.5 MPa.
As described above, when the cooling water supply pressure to be set is 0.1 to 0.5 MPa, the cooling water having an appropriate supply pressure is supplied to the chamber so that the abnormal water pressure does not act on the chamber more reliably. Can be controlled.

At this time, it is preferable that the predetermined value of the supply pressure of the cooling water when the pressure is released by the pressure release valve is 0.5 MPa (Claim 3).
Thus, if the predetermined value of the supply pressure of the cooling water when the pressure is released by the pressure release valve is 0.5 MPa, it is possible to more reliably prevent the excessive pressure from acting on the chamber.

Also, at this time, it has a temperature sensor for measuring the temperature of the supplied cooling water, and the temperature of the cooling water is periodically measured and recorded by the temperature sensor, and the recorded temperature is larger than the allowable maximum temperature. In such a case, an alarm can be issued (claim 4).
In this way, it has a temperature sensor for measuring the temperature of the supplied cooling water, periodically measures and records the temperature of the cooling water with the temperature sensor, and the recorded temperature is larger than the allowable maximum temperature. If an alarm is issued in this case, the abnormality of the cooling water can be easily detected by the change in temperature, and the abnormality detection time can be improved more reliably.

  In addition, the present invention is a method for heating a raw material in a crucible accommodated in a chamber with a heater to form a raw material melt, depositing a seed crystal in the heated raw material melt, and growing a single crystal below. A method for producing a single crystal by a Larsky method, wherein the chamber is divided into a plurality of chambers, and individual cooling water paths are provided for cooling by supplying and discharging cooling water for each of the divided chambers, The flow rate and pressure of cooling water to be supplied for each cooling water path are set, the flow rate of cooling water discharged from each of the divided chambers is periodically measured and recorded, and the recorded flow rate is predetermined. When the pressure is smaller than the value, an alarm is issued, and the cooling water supply pressure for each of the cooling water paths is measured, and when the pressure exceeds a predetermined value, the cooling water supply pressure of the cooling water path is released. To be characterized by That provides a single-crystal manufacturing method (claim 5).

  In this manner, the chamber is divided into a plurality of parts, and individual cooling water paths are provided for cooling by supplying and discharging cooling water for each of the divided chambers, and the cooling water paths are supplied to the respective cooling water paths. Set the flow rate and pressure of the cooling water, periodically measure and record the flow rate of the cooling water discharged from each of the divided chambers, and alert when the recorded flow rate is smaller than the set flow rate If the cooling water supply pressure for each cooling water path is measured and the cooling water supply pressure in the cooling water path is released when the pressure exceeds a predetermined value, Control can be performed so that abnormal water pressure does not work, and damage to the chamber due to excessive pressure can be prevented. In addition, it is possible to efficiently cool the chambers by supplying cooling water having an appropriate flow rate to the respective chambers, and to prevent local increase in temperature. Furthermore, the abnormality of the cooling water can be easily detected by the change in the flow rate, and the abnormality detection time can be improved.

At this time, it is preferable that the cooling water supply pressure to be set is 0.1 to 0.5 MPa.
Thus, if the cooling water supply pressure to be set is set to 0.1 to 0.5 MPa, cooling water with an appropriate supply pressure is supplied to the chamber so that the abnormal water pressure does not act on the chamber more reliably. Can be controlled.

At this time, it is preferable that a predetermined value of the supply pressure of the cooling water when releasing the pressure is 0.5 MPa (Claim 7).
Thus, if the predetermined value of the supply pressure of the cooling water at the time of releasing the pressure is 0.5 MPa, it is possible to more reliably prevent the excessive pressure from acting on the chamber.

At this time, the temperature of the supplied cooling water is periodically measured and recorded, the recorded temperature is compared with the allowable maximum temperature, and an alarm is issued if the recorded temperature is higher than the allowable maximum temperature. (Claim 8).
In this way, the temperature of the supplied cooling water is periodically measured and recorded, the recorded temperature is compared with the allowable maximum temperature, and an alarm is issued if the recorded temperature is greater than the allowable maximum temperature. If so, it is possible to easily detect an abnormality in the cooling water due to a change in temperature, and the abnormality detection time can be improved more reliably.

  In the present invention, in the single crystal manufacturing apparatus, the flow rate and pressure of the cooling water supplied to each divided chamber are set in the pressure adjustment valve and the flow rate adjustment valve for each cooling water path, and the divided chambers are set. The flow rate of cooling water discharged from the system is periodically measured and recorded with a digital flow meter, and an alarm is issued when the recorded flow rate is smaller than a predetermined value, and the cooling water supply pressure for each cooling water path When the pressure exceeds a predetermined value, the supply pressure of the cooling water is released by the pressure release valve of the cooling water path, so that control is performed so that abnormal water pressure does not work in each chamber. The chamber can be prevented from being damaged by excessive pressure. In addition, it is possible to efficiently cool the chambers by supplying cooling water having an appropriate flow rate to the respective chambers, and to prevent local increase in temperature. Furthermore, the abnormality of the cooling water can be easily detected by the change in the flow rate, and the abnormality detection time can be improved.

Hereinafter, although an embodiment is described about the present invention, the present invention is not limited to this.
Conventionally, the supply pressure of cooling water to each of the divided chambers has been centrally managed at a single location using a centralized supply device in a factory. However, if the pressure cannot be adjusted with the centralized supply device and the cooling water pressure exceeds the design pressure of the chamber, the chamber is damaged and the cooling water enters the furnace, and the cooling water contacts the melted raw material melt. There is a possibility, and conventional pressure management was insufficient.

  In addition, an alarm is issued when the cooling water stops flowing. However, because the switch for detecting an abnormality is activated by the pressure of the cooling water, it is difficult to set the alarm reporting at the alarm flow rate, and the flow control is thorough. I couldn't say that.

  Therefore, the present inventor has intensively studied to solve such problems. As a result, if a separate cooling water path is provided for each of the divided chambers, and pressure adjustment is performed on each cooling water path, abnormal water pressure is applied to each chamber even when pressure adjustment by centralized control becomes impossible. I thought that it can be controlled so that does not work. In addition, the inventors have completed the present invention by conceiving that an abnormality in cooling water can be easily and quickly detected by adjusting the flow rate of cooling water for each cooling water path and monitoring changes in the flow rate and temperature. It was.

FIG. 1 shows a schematic diagram of an example of a single crystal manufacturing apparatus according to the present invention. Moreover, the cross-sectional schematic is shown in FIG.
As shown in FIG. 2, the chamber is divided into a plurality of parts, and includes a pull chamber 2, a top chamber 3, and a main chamber 4. The crucibles 8 and 9 for storing the raw material melt 7, the heater 10 for heating and melting the polycrystalline raw material, and the like are stored in the main chamber 4 and the top chamber 3. In the example of the single crystal manufacturing apparatus shown in FIGS. 1 and 2, the chamber is divided into three, but the number of divisions is not particularly limited. For example, the main chamber 4 may be further divided into a middle chamber and a bottom chamber. .

  The pull chamber 2 is connected to the top chamber 3, and a pulling mechanism 20 for pulling the grown single crystal is provided above the pull chamber 2. A wire 19 is unwound from the pulling mechanism 20, and a seed holder 18 for attaching the seed crystal 17 is connected to the tip of the wire 19. The seed crystal 17 attached to the tip of the seed holder 18 is used as a raw material melt. 7, the single crystal rod 6 is pulled up and grown below the seed crystal 17 by winding the wire 19 by the pulling mechanism 20. In this case, an isolation valve 28 is provided between the pull chamber 2 and the top chamber 3 to shut off the pull chamber 2 and the top chamber 3 when the grown single crystal is taken out.

  The crucibles 8 and 9 are composed of a quartz crucible 8 that directly accommodates the raw material melt 7 inside, and a graphite crucible 9 for supporting the quartz crucible 8. The crucibles 8 and 9 are supported on a crucible rotating shaft 21 that can be rotated up and down by a rotation drive mechanism (not shown) attached to the lower part of the single crystal manufacturing apparatus 1. The crucible rotating shaft 21 is opposite to the single crystal rod 6 in order to keep the melt surface at a certain position so that the crystal quality does not change due to the change in the surface position of the raw material melt 7 in the single crystal production apparatus 1. The crucibles 8 and 9 are raised as much as the raw material melt 7 decreases in accordance with the pulling up of the single crystal rod 6 while rotating.

In addition, a heater 10 is disposed so as to surround the crucibles 8 and 9, and heat from the heater 10 is prevented from being directly radiated to the main chamber 4 and the top chamber 3 outside the heater 10. A heat insulating member 22 is provided so as to surround the periphery.
The pull chamber 2, the top chamber 3, and the main chamber 4 are filled with an argon gas or the like from a gas inlet 23 provided at the top of the pull chamber 2 for the purpose of discharging impurity gas generated in the furnace to the outside of the furnace. An inert gas is introduced, passes through the upper part of the single crystal rod 6 and the melt 7 that are being pulled up, flows through the top chamber 3 and the main chamber 4, and is discharged from a gas outlet 24 provided in the base plate 5.

Furthermore, in order to cool the growing single crystal more effectively, it extends from the ceiling of the top chamber 3 toward the surface of the raw material melt 7 so as to surround the single crystal being pulled, and is introduced from the cooling medium inlet. A cooling cylinder 25 forcibly cooled by the cooled cooling medium and a cooling auxiliary member 26 extending downward from the cooling cylinder 25 may be provided.

Each of these chambers has a structure in which cooling water for cooling the chamber is circulated to protect each chamber and prevent the radiant heat of the heater 10 inside the chamber from being transmitted to the outside of the single crystal manufacturing apparatus 1. It can be blocked. Here, the pull chamber 2, the top chamber 3, the main chamber 4, the base plate 5, and the cooling cylinder 25 can be manufactured from a metal excellent in heat resistance and heat conductivity such as stainless steel.
Further, as shown in FIG. 1, individual cooling water paths are provided for each of the divided chambers (the pull chamber 2, the top chamber 3, and the main chamber 4). Each cooling water path has a cooling water inlet main pipe at the inlet of the path, and then has a cooling water outlet main pipe through each chamber and at the outlet of the path. Here, for example, as shown in FIG. 1, the base plate 5 at the bottom of the main chamber 4 or the isolation valve 28 between the pull chamber 2 and the top chamber 3 is also cooled, so that the cooling water path of the present invention is provided. Can do.

Then, on each cooling water path, the pressure adjusting valve 11 for adjusting the supply pressure of the cooling water supplied to each chamber, the flow rate adjusting valve 12 and the flow meter 13 for adjusting the flow rate, and the supply pressure of the cooling water are released. And a digital flow meter 15 for measuring the flow rate of the cooling water discharged from the chamber.
Further, as shown in FIG. 1, these members are arranged in the order of the pressure regulating valve 11, the flow regulating valve 12, the flow meter 13, the chamber, the pressure release valve 14, and the digital flow meter 15 in this order from the inlet of the cooling water path. Can be set.

Although not particularly limited here, for example, the flow meter 13 can be an area type, and the flow rate adjustment valve 12 can be a ball valve.
And the flow volume and pressure of the cooling water supplied to each chamber can be set to the pressure regulating valve 11 and the flow regulating valve 12 for each cooling water path.
Further, the flow rate of the cooling water discharged from each chamber is periodically measured and recorded by the digital flow meter 15, and an alarm can be issued when the recorded flow rate is smaller than a predetermined value. Yes. Here, the predetermined value can be set to a flow rate set in the flow rate adjustment valve 12, for example.

Here, the digital flow meter 15 preferably has a flow measurement accuracy within ± 1% of the measurable range. Further, although not particularly limited, the interval at which the flow rate of the coolant is periodically measured and recorded can be set, for example, every second.
Further, when the cooling water supply pressure for each cooling water path is measured and the pressure exceeds a predetermined value, the cooling water supply pressure is released by the pressure release valve 14 of the cooling water path. ing.

  In the single crystal manufacturing apparatus of the present invention, in this way, for example, even when an abnormality occurs in an apparatus that centrally manages the pressure of cooling water, abnormal water pressure does not work in each chamber. Thus, the chamber can be prevented from being damaged by excessive pressure. Further, it is possible to prevent each chamber from being heated by supplying an appropriate flow rate of cooling water to each chamber efficiently to prevent local increase in temperature. It is possible to prevent deformation and alteration of a member such as a ring. Furthermore, the abnormality of the cooling water can be easily detected by the change in the flow rate. In addition, the abnormality detection time can be improved, and the operator can deal with it before the temperature of the chamber becomes high, so that damage to the chamber can be prevented.

  The set value of the flow rate of the cooling water set in the flow rate adjusting valve 12 can be a value obtained by the setting procedure as shown in FIG. That is, as shown in FIG. 3, first, the heat removal amount of the cooling water is estimated (FIG. 3a), and a provisional set value is determined (FIG. 3b). Next, a heating test is performed with the actual flow rate set to a temporary set value. At this time, the temperature of the cooling water supplied to the chamber and the temperature of the cooling water discharged from the chamber are measured, and the flow rate is adjusted so that the input / output temperature difference becomes 15 ° C. (FIG. 3c). Then, the adjusted flow rate is determined as a set value (FIG. 3d).

  Further, as shown in FIG. 3, the amount of heat removal from the cooling water is estimated to determine a provisional alarm flow rate (FIG. 3b), and when the input / output temperature difference is adjusted to 20 ° C. in the same manner as described above. The flow rate can be obtained (FIG. 3e), and the flow rate can be obtained as the set alarm flow rate (FIG. 3f). When the flow rate set by the flow rate adjusting valve 12 is set as the set value determined in the above procedure, the flow rate of the cooling water discharged from the chamber measured by the digital flow meter 15 is smaller than the set alarm flow rate. An alarm can be issued.

At this time, it is preferable that the cooling water supply pressure to be set is 0.1 to 0.5 MPa.
Thus, if the cooling water supply pressure to be set is 0.1 to 0.5 MPa, the cooling water having an appropriate supply pressure is supplied to each chamber, and the abnormal water pressure does not work on the chamber more reliably. Can be controlled.

At this time, it is preferable that the predetermined value of the supply pressure of the cooling water when the pressure is released by the pressure release valve 14 is 0.5 MPa.
Thus, if the pressure is released by the pressure release valve 14 when the supply pressure of the cooling water exceeds 0.5 MPa, it is possible to more reliably prevent the excessive pressure from acting on the chamber.

At this time, the digital flow meter 15 is preferably disposed in the vicinity of the cooling water outlet where the flow rate becomes the smallest due to the resistance of the cooling water path, that is, in the vicinity of the cooling water outlet main pipe.
Thus, if the minimum flow rate on the path is measured and the cooling water is monitored, the abnormality of the cooling water can be detected more reliably and quickly.

At this time, it has a temperature sensor 16 for measuring the temperature of the supplied cooling water, and the temperature sensor 16 periodically measures and records the temperature of the cooling water, and the recorded temperature is higher than the allowable maximum temperature. An alarm may be issued in case. Here, the allowable maximum temperature can be set to 60 ° C., for example.
In this way, the temperature sensor 16 that measures the temperature of the supplied cooling water is provided, and the temperature sensor 16 periodically measures and records the temperature of the cooling water, and the recorded temperature is higher than the allowable maximum temperature. If an alarm is issued in this case, it is possible to easily detect the abnormality of the cooling water by changing the temperature in addition to the flow rate, and the abnormality detection time can be improved more reliably. Further, even when the digital flow meter 15 that measures the flow rate fails, an abnormality of the cooling water can be detected by a change in temperature.

Here, the temperature sensor 16 can be disposed in the vicinity of the flange 27 (black dot in FIG. 1) near the discharge port for discharging the cooling water from each chamber.
In this way, if the temperature is measured in the vicinity of the flange 27 near the discharge port where the temperature of the cooling water is highest in the chamber and the cooling water is monitored, the abnormality of the cooling water can be detected more reliably and quickly. it can.

Next, the method for producing a single crystal according to the present invention will be described.
Here, the case where the single crystal manufacturing apparatus according to the present invention as shown in FIG. 1 is used will be described with reference to FIGS. As described above, in the single crystal manufacturing apparatus 1 shown in FIG. 1, the chamber is divided into a plurality of parts, and an individual cooling water path is provided for each of the divided chambers.
First, as shown in FIG. 2, a high-purity polycrystalline silicon raw material of silicon is heated to a melting point (about 1420 ° C.) or higher in a crucible 8 or 9 to be a raw material melt 7.

At this time, the cooling water is supplied to the respective chambers from the individually provided cooling water paths. At this time, the pressure and flow rate of the cooling water supplied for each cooling water path are set to desired values using the pressure adjustment valve 11, the flow rate adjustment valve 12, and the flow meter 13.
The value of the flow rate set here can be a value obtained by the setting procedure shown in FIG. 3 as described above, for example.
In order to monitor the cooling water, the flow rate of the cooling water discharged from each of the divided chambers is periodically measured and recorded by the digital flow meter 15, and the recorded flow rate is smaller than a predetermined value. Alarm in case. Here, the interval at which the flow rate of the coolant is periodically measured and recorded can be set, for example, every second. Further, the predetermined value can be a flow rate set in the flow rate adjustment valve 12. Alternatively, the predetermined alarm flow rate obtained by the setting procedure shown in FIG.
Also, the cooling water supply pressure for each cooling water path is measured, and when the pressure exceeds a predetermined value, the cooling water supply pressure of the cooling water path is released.

  In the method for producing a single crystal according to the present invention, by doing so, it is possible to control the abnormal water pressure from acting on each chamber, and it is possible to prevent damage to the chamber due to excessive pressure. In addition, each chamber can be efficiently cooled by supplying cooling water at an appropriate flow rate to each chamber, and local temperature rise can be prevented. Furthermore, the abnormality of the cooling water can be easily detected by the change in the flow rate, and the abnormality detection time can be improved.

At this time, it is preferable that the cooling water supply pressure to be set is 0.1 to 0.5 MPa.
Thus, if the cooling water supply pressure to be set is 0.1 to 0.5 MPa, it is possible to supply the cooling water with an appropriate supply pressure to the chamber, to ensure an appropriate flow rate more reliably, and to cause abnormalities in the chamber. It is possible to control so that no water pressure works.

At this time, it is preferable that the predetermined value of the supply pressure of the cooling water when releasing the pressure is 0.5 MPa.
Thus, if the predetermined value of the supply pressure of the cooling water when releasing the pressure is 0.5 MPa, it is possible to more reliably prevent the excessive pressure from acting on the chamber.

At this time, the temperature of the supplied cooling water is periodically measured and recorded, the recorded temperature is compared with the allowable maximum temperature, and an alarm is issued if the recorded temperature is higher than the allowable maximum temperature. Can do. Here, the allowable maximum temperature can be set to 60 ° C., for example.
In this way, the temperature of the supplied cooling water is periodically measured and recorded, the recorded temperature is compared with the maximum allowable temperature, and if the recorded temperature is greater than the maximum allowable temperature, an alarm is issued. For example, it is possible to easily detect the abnormality of the cooling water by changing the temperature in addition to the flow rate, and the abnormality detection time can be improved more reliably. Further, even when the digital flow meter 15 that measures the flow rate fails, an abnormality of the cooling water can be detected by a change in temperature.

  Next, the wire 19 is unwound so that the tip of the seed crystal 17 is deposited on the approximate center of the molten metal surface. Then, the single crystal rod 6 having a desired quality is grown by expanding the diameter to a desired diameter. Thereafter, the single crystal rod 6 can be manufactured by rotating the crucible holding shaft 21 in an appropriate direction, winding the wire 19 while rotating it, and pulling up the seed crystal 17.

  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
A silicon single crystal having a diameter of 200 mm was grown using a single crystal manufacturing apparatus in which the main chamber of the single crystal manufacturing apparatus according to the present invention as shown in FIG. 1 is further divided into a middle chamber and a bottom chamber. Here, a cooling water concentration supply device of a factory is connected to the single crystal manufacturing device as a cooling water supply source, and the cooling water pressurized by the cooling water concentration supply device is introduced from the cooling water inlet main pipe at the inlet of the cooling water path. The configuration is as follows. And the supply pressure of the cooling water supplied to each chamber at the time of changing the supply pressure in the cooling water concentration supply apparatus during single crystal growth was measured and evaluated with a pressure gauge.

Here, the set pressure of the single crystal manufacturing apparatus was set to 0.3 MPa, and the supply pressure in the cooling water concentrated supply apparatus was changed from the initial value of 0.3 MPa to 0.4 MPa after the raw material was melted.
The results are shown in Table 1. As shown in Table 1, it can be seen that even if the supply pressure in the cooling water concentration supply device changes, the pressure acting on each chamber does not change, and the pressure according to the set pressure works.
As a result, the single crystal manufacturing apparatus and the single crystal manufacturing method according to the present invention supply an appropriate amount of flow rate, and control the pressure acting on the chamber to be constant even when the pressure on the factory supply side becomes higher than the set pressure. It was confirmed that the chamber could be prevented from being damaged by excessive pressure.

(Example 2)
A silicon single crystal having a diameter of 200 mm was grown using the same single crystal manufacturing apparatus as in Example 1, and the time until an alarm was issued when the flow rate of cooling water to the middle chamber was reduced during the growth was evaluated. Here, the set flow rate was 55 L / min, and the flow rate was reduced to 10 L / min during the growth. Further, when an alarm is issued, an alarm is issued when the flow rate measured by the digital flow meter becomes smaller than the flow rate set in the flow rate adjustment valve, that is, 55 L / min.

The results are shown in Table 2. As shown in Table 2, it can be seen that a decrease in the flow rate is sensed and a warning is issued in a shorter time than the result of Comparative Example 2 described later.
Accordingly, it was confirmed that the single crystal manufacturing apparatus and the single crystal manufacturing method according to the present invention can improve the cooling water abnormality detection time.

Example 3
Except for changing the amount by which the flow rate of cooling water to the middle chamber was reduced, the longest time to grow a silicon single crystal and issue an alarm in the same manner as in Example 2, and the flange of the chamber when the alarm was issued The temperature of the cooling water and the temperature of the cooling water when an alarm was issued were evaluated.
The result of the time until the alarm is issued is shown in FIG. As shown in FIG. 4, it can be seen that the time until the alarm is issued is substantially constant. On the other hand, in Comparative Example 3 to be described later, it can be seen that the longest time until the alarm is issued increases as the amount of decreased flow increases.

  The result of the temperature of the chamber flange when the alarm is issued is shown in FIG. As shown in FIG. 5, it can be seen that the temperature of the flange of the chamber when the alarm is issued is substantially constant. On the other hand, in Comparative Example 3 to be described later, it can be seen that the temperature of the flange of the chamber increases when the alarm is issued as the amount of decrease in the flow rate increases.

  The result of the temperature of the cooling water when the alarm is issued is shown in FIG. As shown in FIG. 6, it can be seen that the temperature of the cooling water when the alarm is issued is substantially constant. On the other hand, in the comparative example 3 mentioned later, it turns out that the temperature of the cooling water at the time of issuing a warning becomes high, so that the quantity which reduced the flow volume increases.

(Comparative Example 1)
The cooling water path of each divided chamber as shown in FIG. 7 does not have a pressure regulating valve, a pressure release valve, and a digital flow meter, and the cooling water supply pressure is controlled by a collective centralized supply device of the entire factory. A silicon single crystal was produced under the same conditions as in Example 1 except that the conventional single crystal production apparatus and production method were used, and the supply pressure of cooling water was evaluated in the same manner as in Example 1.
The results are shown in Table 3. As shown in Table 3, it can be seen that the pressure acting on the chamber changes as the supply pressure in the cooling water concentration supply device changes. If the supply pressure on the factory side becomes larger than the design pressure of the chamber, it is easily inferred from this that the pressure acts on the chamber and the chamber is damaged. In addition, it can be seen that the actual flow rate and the flow rate at the time of alarming change with respect to the set flow rate and the set alarm flow rate as compared with Table 1 of Example 1 due to the instability of the flow switch.

(Comparative Example 2)
Except for using the same conventional single crystal manufacturing apparatus and manufacturing method as in Comparative Example 1, a silicon single crystal was manufactured under the same conditions as in Example 2, and the time until an alarm was issued in the same manner as in Example 2 was set. evaluated.
The results are shown in Table 4. As shown in Table 4, it can be seen that it takes time to issue an alarm as compared with Example 2.

(Comparative Example 3)
The maximum time until a silicon single crystal is produced under the same conditions as in Example 3 and an alarm is issued in the same manner as in Example 3 except that the conventional single crystal production apparatus and production method similar to those in Comparative Example 1 are used. The temperature of the flange of the chamber when the alarm was issued and the temperature of the cooling water when the alarm was issued were evaluated.

The result of the time until the alarm is issued is shown in FIG. As shown in FIG. 4, it can be seen that the longer the amount of decrease in the flow rate, the longer the longest time until an alarm is issued.
The result of the temperature of the chamber flange when the alarm is issued is shown in FIG. As shown in FIG. 5, it can be seen that the greater the amount by which the flow rate is reduced, the higher the temperature of the flange of the chamber when the alarm is issued.
The result of the temperature of the cooling water when the alarm is issued is shown in FIG. As shown in FIG. 6, it can be seen that the temperature of the cooling water when the alarm is issued increases as the amount of decrease in the flow rate increases.

  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 which shows an example of the single crystal manufacturing apparatus which concerns on this invention. It is the cross-sectional schematic of the single crystal manufacturing apparatus shown in FIG. It is a figure which shows an example of the setting procedure of the setting value of the flow volume of the cooling water which can be used with the single crystal manufacturing apparatus and single crystal manufacturing method which concern on this invention, and a setting alarm flow volume. It is a figure which shows the result of the time until issuing the alarm of Example 3 and the comparative example 3. FIG. It is a figure which shows the result of the temperature of the flange of a chamber when issuing the alarm of Example 3 and the comparative example 3. FIG. It is a figure which shows the result of the temperature of the cooling water when the alarm of Example 3 and the comparative example 3 was issued. It is the schematic which shows an example of the conventional single crystal manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Single crystal manufacturing apparatus, 2 ... Pull chamber, 3 ... Top chamber,
4 ... main chamber, 5 ... base plate, 6 ... single crystal rod,
7 ... Raw material melt, 8, 9 ... Crucible, 10 ... Heater, 11 ... Pressure regulating valve,
12 ... Flow control valve, 13 ... Flow meter, 14 ... Pressure release valve, 15 ... Digital flow meter,
16 ... Temperature sensor, 17 ... Seed crystal, 18 ... Seed holder, 19 ... Wire,
20 ... Pulling mechanism, 21 ... Crucible rotating shaft, 22 ... Heat insulation member, 23 ... Gas inlet,
24 ... Gas outlet, 25 ... Cooling cylinder, 26 ... Cooling auxiliary member, 27 ... Flange,
28 ... Isolation valve.

Claims (8)

A single crystal by the Czochralski method in which the raw material in the crucible accommodated in the chamber is heated by a heater to form a raw material melt, a seed crystal is deposited in the heated raw material melt, and a single crystal is grown below. Manufacturing equipment,
The chamber is divided into a plurality of parts, each of the divided chambers has an individual cooling water path for cooling by supplying and discharging cooling water, and the chamber is supplied to the chamber on each cooling water path A pressure adjusting valve for adjusting the supply pressure of the cooling water, a flow rate adjusting valve and a flow meter for adjusting the flow rate, a pressure release valve for releasing the supply pressure of the cooling water, and a flow rate of the cooling water discharged from the chamber A digital flow meter to measure
The flow rate and pressure of the cooling water supplied to each of the divided chambers are set in the pressure adjustment valve and the flow rate adjustment valve for each of the cooling water paths, and the cooling water discharged from each of the divided chambers. The water flow rate is periodically measured and recorded by the digital flow meter, an alarm is issued when the recorded flow rate is smaller than a predetermined value, and the cooling water supply pressure for each of the cooling water paths is measured. When the pressure exceeds a predetermined value, the cooling water supply pressure is released by the pressure release valve in the cooling water path.   The apparatus for producing a single crystal according to claim 1, wherein the cooling water supply pressure to be set is 0.1 to 0.5 MPa.   The single crystal manufacturing apparatus according to claim 1 or 2, wherein a predetermined value of a supply pressure of the cooling water when the pressure is released by the pressure release valve is 0.5 MPa.   A temperature sensor for measuring the temperature of the supplied cooling water, periodically measuring and recording the temperature of the cooling water with the temperature sensor, and providing an alarm when the recorded temperature is greater than the allowable maximum temperature. The single crystal manufacturing apparatus according to any one of claims 1 to 3, wherein the single crystal manufacturing apparatus is a device that emits light. A single crystal by the Czochralski method in which the raw material in the crucible accommodated in the chamber is heated by a heater to form a raw material melt, a seed crystal is deposited in the heated raw material melt, and a single crystal is grown below. A manufacturing method comprising:
The chamber is divided into a plurality of parts, and individual cooling water paths are provided for cooling by supplying and discharging the cooling water for each of the divided chambers, and the flow rate of the cooling water supplied for each of the cooling water paths And set the pressure, periodically measure and record the flow rate of the cooling water discharged from each of the divided chambers, and issue an alarm when the recorded flow rate is smaller than a predetermined value, A method for producing a single crystal, comprising: measuring a cooling water supply pressure for each cooling water path and releasing the cooling water supply pressure in the cooling water path when the pressure exceeds a predetermined value.   6. The method for producing a single crystal according to claim 5, wherein the supply pressure of the cooling water to be set is 0.1 to 0.5 MPa.   The method for producing a single crystal according to claim 5 or 6, wherein a predetermined value of a supply pressure of the cooling water when releasing the pressure is 0.5 MPa. The temperature of the supplied cooling water is periodically measured and recorded, the recorded temperature is compared with an allowable maximum temperature, and an alarm is issued when the recorded temperature is higher than the allowable maximum temperature. The method for producing a single crystal according to any one of claims 5 to 7.

Images